Rosario G. Anera, PhD, Jose R. Jiménez, PhD, Luis Jiménez del Barco, PhD, Javier Bermúdez, PhD, Enrique Hita, PhD

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Rosario G. Anera, PhD, Jose R. Jiménez, PhD, Luis Jiménez del Barco, PhD, Javier Bermúdez, PhD, Enrique Hita, PhD"

Transcription

1 Changes in corneal asphericity after laser in situ keratomileusis Rosario G. Anera, PhD, Jose R. Jiménez, PhD, Luis Jiménez del Barco, PhD, Javier Bermúdez, PhD, Enrique Hita, PhD Purpose: To analyze the origin of the changes in corneal asphericity (p-factor) after laser in situ keratomileusis (LASIK) and the effect of postsurgery asphericity on contrast-sensitivity function (CSF) under photopic conditions. Setting: Department of Optics, University of Granada, Granada, Spain. Methods: The p-factor and CSF (best corrected before surgery and 1, 3, and 6 months after surgery) were measured in 24 eyes. Results: An increase in the p-factor after LASIK was noted; there was an 87.2% change in the asphericity using the paraxial formula of Munnerlyn and coauthors. Other factors such as decentration, type of laser, optical role of the flap, wound healing, biomechanical effects, technical procedures, and reflection losses of the laser on the cornea could account for the greater than expected increase (12.8%) in the p-factor. The CSF measurements deteriorated after LASIK; the change was significant (P.05) in patients with myopia worse than 4.0 diopters at frequencies of 9.2, 12, 15, and 20 cycles per degree. Conclusion: The increase in corneal asphericity after surgery, greater with a higher degree of myopia, and the deterioration in CSF with high myopia justify new ablation algorithms and further study of the variables that could modify the ablation unpredictably. J Cataract Refract Surg 2003; 29: ASCRS and ESCRS In recent years, many studies have demonstrated increased aberrations, particularly a strong increase in the spherical aberration, after refractive surgery. 1 5 These increases notably affect the visual function of the patient 1,2,4,6 in terms of contrast-sensitivity function (CSF) and visual acuity at low luminance. Experimental studies also show changes in postsurgery corneal asphericity; ie, the anterior cornea s change from prolate to oblate. 1,6,7 Except those for customized corneal ablation, most ablation algorithms, although proprietary, are based on the paraxial formula of Munnerlyn and coauthors, 8 in which the ablation depth, s(y), is given by Accepted for publication September 19, Reprint requests to Rosario G. Anera, Departamento de Óptica, Facultad de Ciencias, Universidad de Granada, Granada 18071, Spain. s y 4Dy2 Dd2 3 3 (1) where D is the number of diopters to correct, d is the diameter of the ablation zone, and y is the radial distance from the optical axis. Recently, an analytical expression was proposed for postsurgery asphericity that explains the increase in spherical aberration and the change in corneal asphericity when the paraxial formula of Munnerlyn and coauthors is used. Jiménez and coauthors 9 have demonstrated that postsurgery corneal asphericity can be described by the following equation: p R 3 R 3 p (2) where p is the postsurgery p-factor, p the presurgery p-factor, and R and R the radii of the anterior cornea before and after surgery, respectively. Given that R R 2003 ASCRS and ESCRS /03/$ see front matter Published by Elsevier Science Inc. doi: /s (02)

2 for myopic eyes and that the factor relating the presurgery and postsurgery asphericity is the cube of the quotients of corneal radii, we would expect a considerable increase in the p-factor after surgery. 9 For an aspherical surface, the spherical aberration is proportional to the p-factor 10 ; this may explain the increase in the spherical aberration. 1 5 Equation 2 is deduced from a minimumsquare analysis, 9 which mathematically calculates the most representative conicoid for the anterior cornea after surgery. The parameters of this conicoid coincide with those given by a corneal topographer. 9 The numerical increase in the value of the postsurgery p-factor has been provided by Holladay and coauthors. 6,7 Although they give average data for the p-factor showing that an increased p-factor could be even higher than predicted by the formula in equation 2, individual data are not reflected. In this study, we attempted to determine the individual p-factor after LASIK and to compare this value with the prediction by equation 2. Such analysis would enable us to establish the extent to which equation 2 can predict postsurgery corneal asphericity and to ascertain whether the alterations in corneal asphericity are due to the ablation algorithm only or whether other parameters are involved. We also attempted to determine the contrast-sensitivity function (CSF) under photopic conditions of illumination in the subjects that participated in the study. The aim was to test whether the deterioration in spatial sensitivity correlated with variations in corneal asphericity as other studies, both experimental 1,2,4 and theoretical, 11 indicate. The experimental results were also analyzed by the degree of myopia to emmetropize, as equation 2 would lead us to expect that variations in corneal asphericity and CSF are greater with a higher degree of myopia. 9,11 Subjects and Methods Subjects Twenty-four eyes of 14 subjects participated in the study. Other studies of postsurgery asphericity 6 and CSF are based on a similar number of patients. Before participation in the study, all subjects provided informed consent in accordance with the Declaration of Helsinki. Laser in situ keratomileusis was performed in a refractive surgery clinic using the Esiris scanning-spot excimer laser (Schwind). The age of the subjects ranged from 21 to 42 years. The mean preoperative spherical refractive error was 4.80 diopters (D) 2.4 (SD) (range 1.25 to 9.00 D). The preoperative spherical refractive error in 14 eyes was equal to or greater than 4.00 D and in 10 eyes, less than 4.00 D. The subjects met the following conditions: After 1 month, they were satisfied with the outcome of the surgery, no longer used any form of optical correction, and the mean postoperative spherical refractive error did not exceed 0.50 D. The Snellen visual acuity comparison was roughly equal to the preoperative visual acuity, higher or 1 line lower. These conditions are important because in determining the CSF, including a greater refractive error (defocus) or worse Snellen visual acuity could diminish the CSF 10,11 and thereby mask the main purpose of this study: to assess the influence of postsurgical corneal asphericity on emmetropic eyes. No patient had preexisting abnormal conditions that might affect contrast sensitivity (glaucoma, corneal or neuro-ophthalmic disease, or cataract). The corneal topography data (curvature radius and p- factor) were taken by a previously calibrated EyeSys 2000 corneal topographer (EyeSys Vision) following the Holladay Diagnostic Summary 15 as in other experimental studies of corneal asphericity. 6,7 The accuracy of the topographer was checked by measuring the radius and corneal asphericity several times, obtaining similar results. The p-factor data provided by the topographer were for a diameter of 4.5 mm. The measurements were taken before and 1, 3, and 6 months after LASIK. Other parameters provided by the corneal topographer could be used since there are alternative ways to express equation 2. For example, this equation could be expressed as a function of the corneal power by simply replacing K n/r and K n/r in the equation. The results for postsurgery asphericity, p, do not depend on whether equation 2 is used as a function of the radius or of the presurgery and postsurgery corneal power. Contrast-Sensitivity Function The CSF test was conducted with the B-VAT II device (Mentor O&O, Inc.) using the following frequencies: 2.4, 3.7, 6.0, 9.2, 12, 15, 20, and 24 cycles per degree (cpd). The postsurgery CSF results for low illumination 5,6,12 clearly demonstrate a significant decrease in CSF relative to the best corrected presurgery data. In high illumination (photopic) conditions, results differ. Some authors report significant declines in the CSF at all frequencies, 1,2,4 some detect a slight, nonsignificant decline, 6 and others find that the CSF recovers to the presurgery values. 13,14 However, these studies used different experimental devices (mainly CSV-1000E and the Stereo Optical FACT chart), most testing up to 18 cpd. 1,12 14 Our study was extended to frequencies of 20 and 24 cpd since although the spatial sensitivity of the subject is less, it is possible to make a broader evaluation of the effect of post-lasik corneal asphericity at higher frequencies. The test was done monocularly (presurgery best corrected and postsurgery) at 6 m under dim ambient illumination and a visual field subtended 2 degrees. The average J CATARACT REFRACT SURG VOL 29, APRIL

3 luminance for all the frequencies was within the photopic range (in all cases greater than 150 cd/m 2 ). This luminance level ensured a pupil size of less than 4.5 mm, 6,10,12 avoiding pupil sizes that would invalidate the data on corneal asphericity from the topographer and not including transition zones that could give misleading results. These transition zones have radii and asphericity different from those of the optical zone (ie, where Munnerlyn s formula is applied, the object of the study) and are partly responsible for the deterioration in the visual image in scotopic vision. Transition zones origin a defocused image on the retina since they have a different power than the corresponding optical zone. In each subject, the CSF was determined using the method of the limits, which is summarized as follows: The subject, beginning with the lowest spatial frequency and the highest contrast value available, was asked to indicate the orientation of the grating from among 3 possibilities. This contrast value was reduced until the subject was unable to answer correctly. The procedure was repeated 3 times. The threshold contrast was the mean of the 3 contrasts perceived by the subject. Once the threshold contrast had been determined, the procedure was repeated using a larger spatial-frequency grating. For statistical analysis, the Student t test was used to compare means. The significance level was Results Figure 1 shows the mean pre- and post-lasik (1, 3, and 6 months) p-factor in the 24 eyes as well as the mean predicted by equation 2. Data include standard errors. The data corresponding to these values in each eye appear in Table 1. The mean p-factor before LASIK was At 1 month, a significant increase in the mean p-factor (1.65) was detected compared to the presurgery data (paired t test, t 8.02, P.0001). At 3 months, the mean p-factor diminished significantly (1.42) compared to the first month (t 2.01, P.02), although it was significantly higher than before surgery (t 7.61, P.0001). At 6 months, the mean p-factor was 1.41, which did not differ significantly from the mean at 3 months (t 0.12, P.89). The differences between 3 and 6 months, on average, were not significant, and thus after 3 months, the asphericity data can be considered stable. At 6 months, the mean p-factor was significantly higher than that predicted by equation 1, which averaged 1.23 (t 2.02, P.03). The CSF results are divided into high myopia (number of diopters to correct 4.0 D) and low myopia (number of diopters to correct 4.0 D). Figures 2 and 3 show the best corrected pre- and post-lasik Figure 1. (Anera) Mean SE pre-lasik, post-lasik (1, 3 and 6 months), and predicted p-factor. CSF values at 6 months. The means at each frequency between 3 and 6 months did not differ significantly (P.05 at all frequencies). In the eyes with low myopia, the postsurgery CSF at all frequencies from 3.7 cpd declined from the best corrected presurgery values, although the differences were not significant (P.05 at all spatial frequencies). Figure 3 presents the mean data in eyes with myopia greater than 4.0 D before and 6 months after LASIK, showing that the postsurgery CSF declined from the best corrected presurgery values. The differences were significant at 9.2 cpd and above (P.05 for 9.2, 12, 15, and 20 cpd), although the difference at 24 cpd was not significant although the P value approached significance (t 1.76, P.09). Discussion The first notable finding was the increase in the postsurgery p-factor in all eyes. This agrees with the theoretical prediction given by equation 2 and with the results reported by Holladay and coauthors. 6 They found a high average rise in the p-factor after refractive surgery; this declined over 6 months to a value that was still higher than the presurgery level. Figure 1 also shows the postsurgery p-factor value predicted by equation 2, indicating that the mean postsurgery asphericity and the individual data change the cornea from prolate to oblate, with a magnitude even greater than that pre- 764 J CATARACT REFRACT SURG VOL 29, APRIL 2003

4 Table 1. Preoperative and postoperative p-factors in the study eyes. Eye Preop Spherical Refractive Error (D) Pre-LASIK p-factor Post-LASIK p-factor (Mo) Predicted p-factor* *Predicted by equation 2 dicted by the formula by Munnerlyn and coauthors, as appears to occur in Holladay and coauthors study. 6 This trend was seen in all subjects. According to equation 2, we might also expect the differences between the pre-lasik and post-lasik p- factors to increase with the degree of myopia. For this, we calculated the Spearman correlation coefficient between the degree of myopia and the numerical difference in the p-factor after 6 months and presurgery. We found a correlation coefficient of 0.90, indicating a high correlation between the 2 variables; ie, experimentally, the difference between the pre-lasik and post-lasik p- factors increased with the degree of myopia. This result justifies the greater spherical aberration (as indicated by experimental results 1,2 ) as myopia increases and a possible deterioration in the visual function, as shown in the study of the CSF data. This trend also appears in Figure 4, which shows the mean corneal asphericity before and 6 months after surgery and the predicted asphericity for the 2 groups of myopia. This figure reveals how, beginning with similar presurgery values, the experimental increase in the corneal asphericity and the predicted value were higher in the 4.0 D group, although the increase in corneal asphericity relative to the presurgery values was significant in both groups. Quantitative analysis of the differences between the predicted and experimental results showed that the experimental p-factor was 12.8% higher than J CATARACT REFRACT SURG VOL 29, APRIL

5 Figure 2. (Anera) Mean SE pre-lasik and post-lasik (6 months) CSF relative to the spatial frequency in the group with myopia less than 4.0 D. The CSF was determined under photopic conditions. Figure 3. (Anera) Mean SE pre-lasik and post-lasik (6 months) CSF relative to the spatial frequency in the group with myopia greater than 4.0 D. The CSF was determined under photopic conditions. predicted. In other words, Munnerlyn and coauthors formula accounts for 87.2% of the change in asphericity. Therefore, the main factor that explains the functional change in corneal asphericity in various experimental works 1,2,6,7 is the ablation algorithm. Up to 100% of differences may be due to other factors (decentration, type of laser, optical role of the flap, wound healing, biomechanical effects, technical procedures, and reflection losses of the laser on the cornea), which can hamper achieving the predicted asphericity. This quantitative analysis was made of the 2 groups of myopia tested (high and low), revealing only slight differences: Munnerlyn and coauthors formula accounts for 87.7% and 86.4% of the change found in the asphericity in the high and low myopia groups, respectively. The results of the present study also support the proposal to modify the ablation algorithms and preferentially use a customized corneal ablation 16 since the algorithms that rely on Munnerlyn and coauthors formula render an oblate character to the cornea, generating a greater degree of aberration. 1,3 On the other hand, the discrepancies (12.8%) between the p-factor of the real postsurgery anterior cornea and the value expected on the basis of equation 2 imply the need for a thorough investigation of the above-mentioned factors that cause these discrepancies and that, in principle, are not taken into account in ablation algorithms. If these factors can further alter the shape of the cornea, they can cause the Figure 4. (Anera) Mean SE pre-lasik, 6 months post-lasik, and predicted p-factor in high ( 4.0 D) and low ( 4.0 D) myopia groups. customized ablation algorithms, which need a high precision to minimize eye aberrations, to fail to generate the desired shape of the cornea. For the CSF, the results for low myopia agree with the results in other studies, 12,13 which show that up to 18 cpd, the differences are not significant. In the lowmyopia group in our study, we found differences from 3.7 cpd, although they were not significant. These results may be explained by a smaller increase in the p- factor with lower myopia values, implying a weaker 766 J CATARACT REFRACT SURG VOL 29, APRIL 2003

6 effect on the CSF by the increase in the spherical aberration 10,11 expected from the change in corneal asphericity. As indicated above, the increase in spherical aberration is proportional to the p-factor. For high myopia, significant differences arose from 9.2 cdp, although the decline at 24 cpd was not significant. In this case, our results agree with those of other authors, 1,2 who report a generalized deterioration in the CSF at all frequencies. In our case, at low frequencies (up to 6 cpd), the differences were not significant (P.05). This is consistent with theoretical works 17 that show that variations in corneal asphericity affect the sensitivity of the subject primarily in the middle- and highfrequency ranges. Our study of CSF was performed under high illumination to achieve greater reliability in the corneal asphericity data given by the corneal topographer and to limit the data to the optical zone of the ablation without considering transitions zones, which could diminish the CSF results. On reducing the pupil size, the contribution of the aberrations is less and therefore their effects may depend strongly on the subject. This situation is presumably responsible for the discrepancies in the experimental results under the photopic condition. In addition, for low myopia, in which the variation in corneal asphericity is less, we would expect a smaller increase in aberrations and thus the postsurgery deterioration in CSF would not be significant. For low illumination, with a larger pupil size, the contribution of the aberrations is greater and thus there would be no disagreement in the experimental results in the deterioration in postsurgery CSF; we would expect that the cause of this deterioration would partly be the change in corneal asphericity. As occurred in our study of corneal asphericity, the results of CSF at high illumination and those published for conditions of low illumination also support the new proposals for ablation algorithms, urging more thorough study of the factors that influence the ablation. This study was limited to satisfied asymptomatic subjects under photopic conditions to avoid variables that could influence the objective of the study determination of the origin of the changes in corneal asphericity and the effect of the changes on the CSF. The results are important for all types of refractive surgery patients; that is, although for some patients other variables may cause symptoms or discomfort after surgery, the limitations of the ablation algorithm are always present. Conclusions We tested the increase in corneal asphericity (pfactor) after refractive surgery predicted by the paraxial formula of Munnerlyn and coauthors. 8 The change in the asphericity expected due to this ablation algorithm accounted for 87.2% of the increase in the p-factor. The additional increase may be due to factors such as decentration, type of laser, optical role of the flap, wound healing, biomechanical effects, technical procedures, and reflection losses of the laser on the cornea. The change in corneal asphericity may explain the significant fall in the CSF at medium and high frequencies in high myopia under photopic conditions. These results demonstrate the effect of asphericity on visual function, reflecting the importance of continuing to investigate the factors that can alter the predicted ablation pattern now that customized ablation algorithms are proposed to reduce aberrations that require high precision in the ablation. References 1. Marcos S. Aberrations and visual performance following standard laser vision correction. J Refract Surg 2001; 17: S596 S Moreno-Barriuso E, Merayo-Lloves J, Marcos S, et al. Ocular aberrations before and after myopic corneal refractive surgery: LASIK-induced changes measured with laser ray tracing. Invest Ophthalmol Vis Sci 2001; 42: Schwiegerling J, Snyder RW. Corneal ablation patterns to correct for spherical aberration in photorefractive keratectomy. J Cataract Refract Surg 2000; 26: Oshika T, Klyce SD, Applegate RA, et al. Comparison of corneal wavefront aberrations after photorefractive keratectomy and laser in situ keratomileusis. Am J Ophthalmol 1999; 127: Applegate RA, Hilmantel G, Howland HC, et al. Corneal first surface optical aberrations and visual performance. J Refract Surg 2000; 16: Holladay JT, Dudeja DR, Chang J. Functional vision and corneal changes after laser in situ keratomileusis determined by contrast sensitivity, glare testing, and corneal topography. J Cataract Refract Surg 1999; 25: Holladay JT, Janes JA. Topographic changes in corneal asphericity and effective optical zone after laser in situ J CATARACT REFRACT SURG VOL 29, APRIL

7 keratomileusis. J Cataract Refract Surg 2002; 28: Munnerlyn CR, Koons SJ, Marshall J. Photorefractive keratectomy: a technique for laser refractive surgery. J Cataract Refract Surg 1988; 14: Jiménez JR, Anera RG, Jiménez del Barco L. Equation for corneal asphericity after refractive surgery. In press, J Refract Surg 2003; 19: Atchison DA, Smith G. Optics of the Human Eye. Oxford, Butterworth-Heinemann, 2000; 167: Jiménez JR, Anera RG, Jiménez del Barco L, Carretero L. Retinal image quality in myopic subjects after refractive surgery. J Mod Opt 2000; 47: Montés-Micó R, Charman WN. Mesopic contrast sensitivity function after excimer laser photorefractive keratectomy. J Refract Surg 2002; 18: Pérez-Santonja JJ, Sakla HF, Alió JL. Contrast sensitivity after laser in situ keratomileusis. J Cataract Refract Surg 1998; 24: Montés-Micó R, Charman WN. Choice of spatial frequency for contrast sensitivity evaluation after corneal refractive surgery. J Refract Surg 2001; 17: Holladay JT. Corneal topography using the Holladay Diagnostic Summary. J Cataract Refract Surg 1997; 23: MacRae SM, Applegate RA, Krueger RR. What is customization? An introduction to customized ablation. In: MacRae SM, Krueger RR, Applegate RA, eds, Customized Corneal Ablation; the Quest for SuperVision. Thorofare, NJ, Slack, 2001; Jiménez JR, Anera RG, Jiménez del Barco L. Effects on visual function by approximations of corneal-ablation profile during refractive surgery. Appl Opt 2001; 40: From the Departamento de Óptica, Facultad de Ciencias, Universidad de Granada, Granada, Spain. Supported by Ministerio de Ciencia y Tecnología grant BFM None of the authors has a financial interest in any product mentioned. David Nesbitt translated the text into English. 768 J CATARACT REFRACT SURG VOL 29, APRIL 2003

Binocular Visual Performance After LASIK

Binocular Visual Performance After LASIK Binocular Visual Performance After LASIK José Ramón Jiménez, PhD; Cesar Villa, MD; Rosario González Anera, PhD; Ramón Gutiérrez, PhD; Luis Jiménez del Barco, PhD ABSTRACT PURPOSE: To analyze binocular

More information

Wavefront technology has been used in our

Wavefront technology has been used in our Wavefront Customized Ablations With the WASCA Asclepion Workstation Sophia I. Panagopoulou, BSc; Ioannis G. Pallikaris, MD ABSTRACT PURPOSE: WASCA (Wavefront Aberration Supported Cornea Ablation) is a

More information

Wavefront Analysis in Post-LASIK Eyes and Its Correlation with Visual Symptoms, Refraction, and Topography

Wavefront Analysis in Post-LASIK Eyes and Its Correlation with Visual Symptoms, Refraction, and Topography Analysis in Post-LASIK Eyes and Its Correlation with Visual Symptoms, Refraction, and Topography Maria Regina Chalita, MD, 1 Sai Chavala, MD, 1 Meng Xu, MS, 2 Ronald R. Krueger, MD, MSE 1 Purpose: To evaluate

More information

Laser refractive surgery is becoming increasingly

Laser refractive surgery is becoming increasingly Correlation of Aberrations With Visual Symptoms Using Wavefront Analysis in Eyes After Laser in situ Keratomileusis Maria Regina Chalita, MD; Meng Xu, MS; Ronald R. Krueger, MD, MSE ABSTRACT PURPOSE: To

More information

From theoretical laser ablation design to real outcomes: implications for optimized corneal refractive surgery

From theoretical laser ablation design to real outcomes: implications for optimized corneal refractive surgery Wavefront Sensing Meeting. Whistler,Canada, Feb 04 From theoretical laser ablation design to real outcomes: implications for optimized corneal refractive surgery Susana Marcos, PhD Instituto de Optica,

More information

The development of videokeratoscopes capable

The development of videokeratoscopes capable Aberrations and Visual Performance Following Standard Laser Vision Correction Susana Marcos, PhD ABSTRACT PURPOSE: To relate the change of ocular aberrations with the change of visual performance produced

More information

Comparison of real and computer-simulated outcomes of LASIK refractive surgery

Comparison of real and computer-simulated outcomes of LASIK refractive surgery 926 J. Opt. Soc. Am. A/ Vol. 21, No. 6/ June 2004 Cano et al. Comparison of real and computer-simulated outcomes of LASIK refractive surgery Daniel Cano, Sergio Barbero, and Susana Marcos Instituto de

More information

Common visual problems in older LASIK patients

Common visual problems in older LASIK patients 丘 子 宏 LASIK 手 術 後 的 視 覺 Visual acuity:the measurement of high contrast Snellen acuity but not other functions under different condition Quality of vision: measure the visual functions in variable condition

More information

Current excimer photoablations correct spherical myopic

Current excimer photoablations correct spherical myopic Analysis of Customized Corneal Ablations: Theoretical Limitations of Increasing Negative Asphericity Damien Gatinel, 1 Jacques Malet, 2 Thanh Hoang-Xuan, 1 and Dimitri T. Azar 1, From the 1 Ophthalmology

More information

Ocular aberrations after wavefront optimized LASIK for myopia

Ocular aberrations after wavefront optimized LASIK for myopia Original Article Ocular aberrations after wavefront optimized LASIK for myopia Prema Padmanabhan, Subam S Basuthkar, Roy Joseph Purpose: To study the change in ocular aberrations after wavefront optimized

More information

Comparison of higher-order aberrations after wavefront-guided laser in situ keratomileusis and laser-assisted subepithelial keratectomy

Comparison of higher-order aberrations after wavefront-guided laser in situ keratomileusis and laser-assisted subepithelial keratectomy J CATARACT REFRACT SURG - VOL 32, MAY 2006 Comparison of higher-order aberrations after wavefront-guided laser in situ keratomileusis and laser-assisted subepithelial keratectomy So-Hyang Chung, MD, In

More information

One of the exciting new research areas in laser

One of the exciting new research areas in laser Future Challenges to Aberration-free Ablative Procedures Cynthia Roberts, PhD One of the exciting new research areas in laser refractive surgery is the development of sophisticated devices to measure the

More information

The future of laser refractive surgery is exciting

The future of laser refractive surgery is exciting The Cornea is Not a Piece of Plastic Cynthia Roberts, PhD Editorial The future of laser refractive surgery is exciting with the potential for ever-improved postoperative visual performance. In the past,

More information

Designing multifocal corneal models to correct presbyopia by laser ablation

Designing multifocal corneal models to correct presbyopia by laser ablation Designing multifocal corneal models to correct presbyopia by laser ablation Aixa Alarcón Rosario G. Anera Luis Jiménez del Barco José R. Jiménez Journal of Biomedical Optics 17(1), 018001 (January 2012)

More information

Temporal evolution of ocular aberrations following laser in situ keratomileusis

Temporal evolution of ocular aberrations following laser in situ keratomileusis Ophthalmic & Physiological Optics ISSN 0275-5408 Temporal evolution of ocular aberrations following laser in situ keratomileusis Antonio Benito 1, Manuel Redondo 2 and Pablo Artal 1 1 Laboratorio de Óptica,

More information

Customized corneal ablation and super vision. Customized Corneal Ablation and Super Vision

Customized corneal ablation and super vision. Customized Corneal Ablation and Super Vision Customized Corneal Ablation and Super Vision Scott M. MacRae, MD; James Schwiegerling, PhD; Robert Snyder, MD, PhD ABSTRACT PURPOSE: To review the early development of new technologies that are becoming

More information

In both photorefractive keratectomy (PRK) and laser in situ

In both photorefractive keratectomy (PRK) and laser in situ Determination of Corneal Asphericity after Myopia Surgery with the Excimer Laser: A Mathematical Model Damien Gatinel, 1 Thanh Hoang-Xuan, 1 and Dimitri T. Azar 1,2,3 PURPOSE. To determine the theoretical

More information

The Evolution of the Optical Zone in Corneal Refractive Surgery. Bruce Drum, Ph.D.

The Evolution of the Optical Zone in Corneal Refractive Surgery. Bruce Drum, Ph.D. The Evolution of the Optical Zone in Corneal Refractive Surgery. Bruce Drum, Ph.D. FDA, Division of Ophthalmic and ENT Devices, Rockville, MD Disclaimer This presentation represents the professional opinion

More information

Customized corneal ablation can be designed. Slit Skiascopic-guided Ablation Using the Nidek Laser. Scott MacRae, MD; Masanao Fujieda

Customized corneal ablation can be designed. Slit Skiascopic-guided Ablation Using the Nidek Laser. Scott MacRae, MD; Masanao Fujieda Slit Skiascopic-guided Ablation Using the Nidek Laser Scott MacRae, MD; Masanao Fujieda ABSTRACT PURPOSE: To present the approach of using a scanning slit refractometer (the ARK 10000) in conjunction with

More information

Active Cyclotorsion Error Correction During LASIK for Myopia and Myopic Astigmatism With the NIDEK EC-5000 CX III Laser

Active Cyclotorsion Error Correction During LASIK for Myopia and Myopic Astigmatism With the NIDEK EC-5000 CX III Laser Active Cyclotorsion Error Correction During LASIK for Myopia and Myopic Astigmatism With the NIDEK EC-5000 CX III Laser Sudhank Bharti, MD; Harkaran S. Bains ABSTRACT PURPOSE: To investigate the predictability

More information

VISX Wavefront-Guided LASIK for Correction of Myopic Astigmatism, Hyperopic Astigmatism and Mixed Astigmatism (CustomVue LASIK Laser Treatment)

VISX Wavefront-Guided LASIK for Correction of Myopic Astigmatism, Hyperopic Astigmatism and Mixed Astigmatism (CustomVue LASIK Laser Treatment) CustomVue Advantage Patient Information Sheet VISX Wavefront-Guided LASIK for Correction of Myopic Astigmatism, Hyperopic Astigmatism and Mixed Astigmatism (CustomVue LASIK Laser Treatment) Statements

More information

THE OPTICAL PERFORMANCE OF THE EYE IS SET BY. Laser In Situ Keratomileusis Disrupts the Aberration Compensation Mechanism of the Human Eye

THE OPTICAL PERFORMANCE OF THE EYE IS SET BY. Laser In Situ Keratomileusis Disrupts the Aberration Compensation Mechanism of the Human Eye Laser In Situ Keratomileusis Disrupts the Aberration Compensation Mechanism of the Human Eye ANTONIO BENITO, MANUEL REDONDO, AND PABLO ARTAL PURPOSE: To study how changes induced on corneal optics by myopic

More information

EDITORIAL Wavefront Guided Ablation

EDITORIAL Wavefront Guided Ablation EDITORIAL Wavefront Guided Ablation SCOTT M. MACRAE, MD, AND DAVID R. WILLIAMS, PHD ADAPTIVE OPTICS WAS FIRST SUGGESTED IN 1953 BY astronomer Horace Babcock to remove the blurring effects of turbulence

More information

Changes in higher order aberrations after wavefront-guided PRK for correction of low to moderate myopia and myopic astigmatism: Two-year follow-up

Changes in higher order aberrations after wavefront-guided PRK for correction of low to moderate myopia and myopic astigmatism: Two-year follow-up European Journal of Ophthalmology / Vol. 17 no. 4, 2007 / pp. 507-514 Changes in higher order aberrations after wavefront-guided PRK for correction of low to moderate myopia and myopic astigmatism: Two-year

More information

Comparison of Retinal Image Quality between SBK and PRK. Allen Boghossian, D.O. Durrie Vision Overland Park, KS

Comparison of Retinal Image Quality between SBK and PRK. Allen Boghossian, D.O. Durrie Vision Overland Park, KS Comparison of Retinal Image Quality between and Allen Boghossian, D.O. Durrie Vision Overland Park, KS Study Design Purpose: To compare optical quality and intraocular scatter between and using double-pass

More information

Comparison Combined LASIK Procedure for Ametropic Presbyopes and Planned Dual Interface for Post-LASIK Presbyopes Using Small Aperture Corneal Inlay

Comparison Combined LASIK Procedure for Ametropic Presbyopes and Planned Dual Interface for Post-LASIK Presbyopes Using Small Aperture Corneal Inlay Comparison Combined LASIK Procedure for Ametropic Presbyopes and Planned Dual Interface for Post-LASIK Presbyopes Using Small Aperture Corneal Inlay Minoru Tomita, MD, PhD 1,2 1) Shinagawa LASIK, Tokyo,

More information

Customized corneal ablation may improve outcomes. Effect of Beam Size on the Expected Benefit of Customized Laser Refractive Surgery

Customized corneal ablation may improve outcomes. Effect of Beam Size on the Expected Benefit of Customized Laser Refractive Surgery Effect of Beam Size on the Expected Benefit of Customized Laser Refractive Surgery Antonio Guirao, PhD; David R. Williams, PhD; Scott M. MacRae, MD ABSTRACT PURPOSE: Customized laser surgery attempts to

More information

EVEN THOUGH EARLY CUSTOMIZED ABLATION RESULTS

EVEN THOUGH EARLY CUSTOMIZED ABLATION RESULTS Separate Effects of the Microkeratome Incision and Laser Ablation on the Eye s Wave Aberration JASON PORTER, MS, SCOTT MACRAE, MD, GEUNYOUNG YOON, PHD, CYNTHIA ROBERTS, PHD, IAN G. COX, PHD, AND DAVID

More information

This is the accepted version of this article. To be published as : This is the author version published as:

This is the accepted version of this article. To be published as : This is the author version published as: QUT Digital Repository: http://eprints.qut.edu.au/ This is the author version published as: This is the accepted version of this article. To be published as : This is the author version published as: Mathur,

More information

Comparison of Higher Order Aberrations and Contrast Sensitivity After LASIK, Verisyse Phakic IOL, and Array Multifocal IOL

Comparison of Higher Order Aberrations and Contrast Sensitivity After LASIK, Verisyse Phakic IOL, and Array Multifocal IOL ORIGINAL ARTICLES Comparison of Higher Order Aberrations and Contrast Sensitivity After LASIK, Verisyse Phakic IOL, and Array Multifocal IOL Sasivimon Chandhrasri, MD; Michael C. Knorz, MD ABSTRACT PURPOSE:

More information

Long-term stability of the posterior cornea after laser in situ keratomileusis

Long-term stability of the posterior cornea after laser in situ keratomileusis ARTICLE Long-term stability of the posterior cornea after laser in situ keratomileusis Joseph B. Ciolino, MD, Stephen S. Khachikian, MD, Michael J. Cortese, OD, Michael W. Belin, MD PURPOSE: To study long-term

More information

Quantification and monitoring of visual disturbances for patients with cataracts using Halo v1.0 software

Quantification and monitoring of visual disturbances for patients with cataracts using Halo v1.0 software Quantification and monitoring of visual disturbances for patients with cataracts using Halo v1.0 software Carolina Ortiz 1, José J. Castro 1, Aixa Alarcón 1, Margarita Soler 1, Rosario G. Anera 1 1 Departament

More information

Wavefront-guided Custom Ablation for Myopia Using the NIDEK NAVEX Laser System

Wavefront-guided Custom Ablation for Myopia Using the NIDEK NAVEX Laser System Wavefront-guided Custom Ablation for Myopia Using the NIDEK NAVEX Laser System Jan Venter, MD ABSTRACT PURPOSE: To determine the predictability, effi cacy, safety, and stability of LASIK using custom ablation

More information

With the increasing popularity of laser in

With the increasing popularity of laser in Are Changes in Ocular Aberrations With Age a Significant Problem for Refractive Surgery? Susana Marcos, PhD ABSTRACT We discuss current knowledge about the change of aberrations with aging, cataract surgery,

More information

Although studies have been published on optical

Although studies have been published on optical Original Articles Total and Corneal Optical Aberrations Induced by Laser in situ Keratomileusis for Hyperopia Lourdes Llorente, OD; Sergio Barbero, PhD; Jesus Merayo, MD, PhD; Susana Marcos, PhD ABSTRACT

More information

Laser in situ keratomileusis (LASIK) 1,2 has become a popular

Laser in situ keratomileusis (LASIK) 1,2 has become a popular Optical Response to LASIK Surgery for Myopia from Total and Corneal Aberration Measurements Susana Marcos, 1 Sergio Barbero, 1 Lourdes Llorente, 1 and Jesús Merayo-Lloves 2 PURPOSE. To evaluate the optical

More information

Higher Order Aberrations and Relative Risk of Symptoms After LASIK

Higher Order Aberrations and Relative Risk of Symptoms After LASIK Higher Order Aberrations and Relative Risk of Symptoms After LASIK Munish Sharma, MD; Brian S. Boxer Wachler, MD; Colin C.K. Chan, MD, FRANZCO ABSTRACT PURPOSE: To understand what level of higher order

More information

Q-factor customized ablation profile for the correction of myopic astigmatism

Q-factor customized ablation profile for the correction of myopic astigmatism J CATARACT REFRACT SURG - VOL 32, APRIL 2006 Q-factor customized ablation profile for the correction of myopic astigmatism Tobias Koller, MD, Hans Peter Iseli, MD, Farhad Hafezi, MD, Michael Mrochen, PhD,

More information

The optical quality of the human eye suffers

The optical quality of the human eye suffers Operative Correction of Ocular Aberrations to Improve Visual Acuity Theo Seiler, MD, PhD; Michael Mrochen, PhD; Maik Kaemmerer, PhD ABSTRACT PURPOSE: Optical aberrations of the human eye degrade the quality

More information

Pharmacological management of night vision disturbances after refractive surgery

Pharmacological management of night vision disturbances after refractive surgery J CATARACT REFRACT SURG - VOL 31, SEPTEMBER 25 Pharmacological management of night vision disturbances after refractive surgery Results of a randomized clinical trial Alessandro Randazzo, MD, Francesco

More information

Total Corneal Power Estimation: Ray Tracing Method versus Gaussian Optics Formula PATIENTS AND METHODS

Total Corneal Power Estimation: Ray Tracing Method versus Gaussian Optics Formula PATIENTS AND METHODS Cornea Total Corneal Power Estimation: Ray Tracing Method versus Gaussian Optics Formula Li Wang, 1 Ashraf M. Mahmoud, 2 Betty Lise Anderson, 3 Douglas D. Koch, 1 and Cynthia J. Roberts 2 PURPOSE. To evaluate

More information

The pinnacle of refractive performance.

The pinnacle of refractive performance. Introducing! The pinnacle of refractive performance. REFRACTIVE SURGERY sets a new standard in LASIK outcomes More than 98% of patients would choose it again. 1 It even outperformed glasses and contacts

More information

Anterior Elevation Maps as the Screening Test for the Ablation Power of Previous Myopic Refractive Surgery

Anterior Elevation Maps as the Screening Test for the Ablation Power of Previous Myopic Refractive Surgery Anterior Elevation Maps as the Screening Test for the Ablation Power of Previous Myopic Refractive Surgery Soo Yong Jeong, MD, Hee-Seung Chin, MD, PhD, Jung Hyub Oh, MD, PhD Department of Ophthalmology,

More information

The development of excimer laser keratorefractive surgery

The development of excimer laser keratorefractive surgery Functional Optical Zone of the Cornea Juan Tabernero, 1 Stephen D. Klyce, 2 Edwin J. Sarver, 3 and Pablo Artal 1 PURPOSE. When keratorefractive surgery is used to treat a central corneal diameter smaller

More information

Advances in the measurement of the eye's

Advances in the measurement of the eye's Visual Benefit of Correcting Higher Order Aberrations of the Eye David Williams, PhD; Geun-Young Yoon, PhD; Jason Porter, MS; Antonio Guirao, PhD; Heidi Hofer, BS; Ian Cox, PhD ABSTRACT There is currently

More information

Aberrations induced in wavefront-guided laser refractive surgery due to shifts between natural and dilated pupil center locations

Aberrations induced in wavefront-guided laser refractive surgery due to shifts between natural and dilated pupil center locations J CATARACT REFRACT SURG - VOL 32, JANUARY 2006 ARTICLES Aberrations induced in wavefront-guided laser refractive surgery due to shifts between natural and dilated pupil center locations Jason Porter, PhD,

More information

Alexandria s Guide to LASIK

Alexandria s Guide to LASIK Alexandria s Guide to LASIK A Community Service Project sponsored by: Wallace Laser Center Your Guide To A Successful LASIK Procedure The word LASIK is actually an acronym for Laser Assisted In-Situ Keratomileusis.

More information

IOL Power Calculation After Myopic LASIK. Hany Helaly, Lecturer of Ophthalmology, Faculty of Medicine, Alexandria University.

IOL Power Calculation After Myopic LASIK. Hany Helaly, Lecturer of Ophthalmology, Faculty of Medicine, Alexandria University. IOL Power Calculation After Myopic LASIK Hany Helaly, Lecturer of Ophthalmology, Faculty of Medicine, Alexandria University. SUPERVISORS Prof. Dr. Mohammad El-Hifnawy Professor of Ophthalmology Faculty

More information

A Contralateral, Randomized Comparison of Optimized Prolate Ablation and Conventional LASIK for Myopia With the NIDEK Excimer Laser Platform

A Contralateral, Randomized Comparison of Optimized Prolate Ablation and Conventional LASIK for Myopia With the NIDEK Excimer Laser Platform ORIGINAL ARTICLES A Contralateral, Randomized Comparison of Optimized Prolate Ablation and Conventional LASIK for Myopia With the NIDEK Excimer Laser Platform Alaa M. El Danasoury, MD, FRCS; Jack Holladay,

More information

final corrected draft

final corrected draft Archived at the Flinders Academic Commons http://dspace.flinders.edu.au/dspace/ This is the author s final corrected draft of this article. It has undergone peer review. Citation for the publisher s version:

More information

KERATOCONUS IS A BILATERAL, ASYMMETRIC, CHRONIC,

KERATOCONUS IS A BILATERAL, ASYMMETRIC, CHRONIC, Comparison of and Intacs for Keratoconus and Post-LASIK Ectasia MUNISH SHARMA, MD, AND BRIAN S. BOXER WACHLER, MD PURPOSE: To evaluate the efficacy of single-segment Intacs and compare with double-segment

More information

Keratoconus Detection Using Corneal Topography

Keratoconus Detection Using Corneal Topography Keratoconus Detection Using Corneal Topography Jack T. Holladay, MD, MSEE, FACS ABSTRACT PURPOSE: To review the topographic patterns associated with keratoconus suspects and provide criteria for keratoconus

More information

Refractive Surgery. Evolution of Refractive Error Correction

Refractive Surgery. Evolution of Refractive Error Correction Refractive Surgery Techniques that correct for refractive error in the eye have undergone dramatic evolution. The cornea is the easiest place to place a correction, so most techniques have focused on modifying

More information

Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye Science in China Series E: Technological Sciences 2007 Science in China Press Springer-Verlag Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human

More information

IOL Calculation After LASIK. Chapter (3)

IOL Calculation After LASIK. Chapter (3) the cornea (P) may be considered as the sum of the power of the anterior (Pa) and posterior (Pp) corneal surfaces, as shown in the formula: P = Pa + Pp = (n2 n1)/r1 + (n3 n2)/r2, where n1 is the refractive

More information

Wavefront-guided versus standard laser in situ keratomileusis in low to moderate myopia

Wavefront-guided versus standard laser in situ keratomileusis in low to moderate myopia VOL. 29 NO. 1 PHILIPPINE JOURNAL OF Ophthalmology MARCH ORIGINAL ARTICLE 2004 Jose Ernesto G. Roces, MD Irwin Y. Cua, MD Mellanie M. Oro, OD Jerome M. Sarmiento, MD Winston L. Villar, MD Ruben Lim Bon

More information

Effect of Pupil Size on Corneal Aberrations before and after Standard, Custom LASIK and Corneal Refractive Therapy

Effect of Pupil Size on Corneal Aberrations before and after Standard, Custom LASIK and Corneal Refractive Therapy Effect of Pupil Size on Corneal Aberrations before and after Standard, Custom LASIK and Corneal Refractive Therapy António Queirós 1, César Villa-Collar 2, José Manuel González-Méijome 1, Jorge Jorge 1,

More information

Key Words: Aberration, LASEK, LASIK, Posterior corneal surface, Wavefront-guided ablation

Key Words: Aberration, LASEK, LASIK, Posterior corneal surface, Wavefront-guided ablation Department of Ophthalmology, Seoul National University College of Medicine 1, Seoul, Korea Seoul Artificial Eye Center, Seoul National University Hospital Clinical Research Institute 2, Seoul, Korea Department

More information

TABLE OF CONTENTS: LASER EYE SURGERY CONSENT FORM

TABLE OF CONTENTS: LASER EYE SURGERY CONSENT FORM 1 BoydVision TABLE OF CONTENTS: LASER EYE SURGERY CONSENT FORM Risks and Side Effects... 2 Risks Specific to PRK... 3 Risks Specific to LASIK... 4 Patient Statement of Consent... 5 Consent for Laser Eye

More information

Risk Factors for Night Vision Complaints after LASIK for Myopia

Risk Factors for Night Vision Complaints after LASIK for Myopia Risk Factors for Night Vision Complaints after LASIK for Myopia Mihai Pop, MD, Yves Payette, MSc Purpose: To study the preoperative risk factors for night vision complaints () after LASIK in a clinical

More information

Life Science Journal 2014;11(9) http://www.lifesciencesite.com. Cross cylinder Challenging cases and their resultswith Nidek Quest (EC-5000)

Life Science Journal 2014;11(9) http://www.lifesciencesite.com. Cross cylinder Challenging cases and their resultswith Nidek Quest (EC-5000) Cross cylinder Challenging cases and their resultswith Nidek Quest (EC-5000) Gamal Mostafa Abo El Maaty, Mohamed Elmoddather, Mahmoud Ibrahem Ghazy, Mohamed Al-Taher Ophthalmology Department, Faculty of

More information

THE BEST OF BOTH WORLDS Dual-Scheimpflug and Placido Reaching a new level in refractive screening

THE BEST OF BOTH WORLDS Dual-Scheimpflug and Placido Reaching a new level in refractive screening THE BEST OF BOTH WORLDS Dual-Scheimpflug and Placido Reaching a new level in refractive screening GALILEI G4 Clinical Applications Corneal Implant Planning The comes with a licensable corneal inlay software

More information

Aberrations caused by decentration in customized laser refractive surgery

Aberrations caused by decentration in customized laser refractive surgery Aberrations caused by decentration in customized laser refractive surgery Diana C. Lozano 1,2 Advisors: Jason Porter 2,3a, Geunyoung Yoon 2,3b, and David R. Williams 2,3a San Diego State University, San

More information

INTRODUCTION. Trans Am Ophthalmol Soc 2006;104:402-413

INTRODUCTION. Trans Am Ophthalmol Soc 2006;104:402-413 ORBSCAN II ASSISTED INTRAOCULAR LENS POWER CALCULATION FOR CATARACT SURGERY FOLLOWING MYOPIC LASER IN SITU KERATOMILEUSIS (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS) BY Henry Gelender MD ABSTRACT Purpose:

More information

Corneal polarimetry after LASIK refractive surgery

Corneal polarimetry after LASIK refractive surgery Journal of Biomedical Optics 111, 014001 January/February 2006 Corneal polarimetry after LASIK refractive surgery Juan M. Bueno Esther Berrio Pablo Artal Universidad de Murcia Laboratorio de Óptica Campus

More information

Laser Vision Correction

Laser Vision Correction How will Laser Vision Correction affect my Lifestyle? Your Guide to Laser Vision Correction The Gift of Better Vision A few things to note after your surgery. As you enjoy your new-and-improved eyesight,

More information

articles Intraocular lens power calculation after corneal refractive surgery: Double-K method Jaime Aramberri, MD

articles Intraocular lens power calculation after corneal refractive surgery: Double-K method Jaime Aramberri, MD articles Intraocular lens power calculation after corneal refractive surgery: Double-K method Jaime Aramberri, MD Purpose: To determine the accuracy of a method of calculating intraocular lens (IOL) power

More information

Case Report Laser Vision Correction on Patients with Sick Optic Nerve: A Case Report

Case Report Laser Vision Correction on Patients with Sick Optic Nerve: A Case Report Case Reports in Ophthalmological Medicine Volume 2011, Article ID 796463, 4 pages doi:10.1155/2011/796463 Case Report Laser Vision Correction on Patients with Sick Optic Nerve: A Case Report Ming Chen

More information

Introducing TOPOGRAPHY-GUIDED REFRACTIVE SURGERY

Introducing TOPOGRAPHY-GUIDED REFRACTIVE SURGERY Sponsored by Introducing TOPOGRAPHY-GUIDED REFRACTIVE SURGERY Results of the T-CAT Phase III Clinical Trial TOPOGRAPHY-GUIDED REFRACTIVE SURGERY Topography-Guided Custom Ablation Treatments (T-CAT) with

More information

SCHWIND CAM Perfect Planning wide range of applications

SCHWIND CAM Perfect Planning wide range of applications SCHWIND CAM Perfect Planning wide range of applications ORK-CAM PresbyMAX PALK-CAM PTK-CAM 2 SCHWIND CAM the system solution The latest version of the modular SCHWIND CAM represents an even more efficient

More information

Financial Disclosure. LASIK Flap Parameters IntraLase Microkeratome 6/9/2008. Femtosecond LASIK Flaps: What Could We Customize Yesterday?

Financial Disclosure. LASIK Flap Parameters IntraLase Microkeratome 6/9/2008. Femtosecond LASIK Flaps: What Could We Customize Yesterday? Financial Disclosure Arturo Chayet, MD Tijuana, BC Mexico Perry S. Binder, MS, MD San Diego CA USA I have the following financial interests or relationships to disclose: AMO/IntraLase Corporation - C Acufocus

More information

INTRACOR. An excerpt from the presentations by Dr Luis Ruiz and Dr Mike Holzer and the Round Table discussion moderated by Dr Wing-Kwong Chan in the

INTRACOR. An excerpt from the presentations by Dr Luis Ruiz and Dr Mike Holzer and the Round Table discussion moderated by Dr Wing-Kwong Chan in the INTRACOR An excerpt from the presentations by Dr Luis Ruiz and Dr Mike Holzer and the Round Table discussion moderated by Dr Wing-Kwong Chan in the 1 Dr Luis Ruiz Presbyopia treatment with INTRACOR Luis

More information

Clinical results and theoretical models of etiology. Peter S. Hersh, MD, Kristen Fry, OD, J. Warren Blaker, PhD

Clinical results and theoretical models of etiology. Peter S. Hersh, MD, Kristen Fry, OD, J. Warren Blaker, PhD Spherical aberration after laser in situ keratomileusis and photorefractive keratectomy Clinical results and theoretical models of etiology Peter S. Hersh, MD, Kristen Fry, OD, J. Warren Blaker, PhD Purpose:

More information

Wavefront Coherence Area for Predicting Visual Acuity of Post-PRK and Post-PARK Refractive Surgery Patients

Wavefront Coherence Area for Predicting Visual Acuity of Post-PRK and Post-PARK Refractive Surgery Patients Wavefront Coherence Area for Predicting Visual Acuity of Post-PRK and Post-PARK Refractive Surgery Patients Daniel D. Garciaa*, Corina van de Polb, Brian A. Barskya,c, Stanley A. Kleinc auniversity of

More information

Wavefront-guided Enhancements Using the WaveLight Excimer Laser in Symptomatic Eyes Previously Treated With LASIK

Wavefront-guided Enhancements Using the WaveLight Excimer Laser in Symptomatic Eyes Previously Treated With LASIK Wavefront-guided Enhancements Using the WaveLight Excimer Laser in Symptomatic Eyes Previously Treated With LASIK A. John Kanellopoulos, MD; Lawrence H. Pe, MD ABSTRACT PURPOSE: To describe our clinical

More information

Retreatment by Lifting the Original Laser in Situ Keratomileusis Flap after Eleven Years

Retreatment by Lifting the Original Laser in Situ Keratomileusis Flap after Eleven Years Retreatment by Lifting the Original Laser in Situ Keratomileusis Flap after Eleven Years Hassan Hashemi, MD 1,2 Mehrdad Mohammadpour, MD 3 Abstract Purpose: To describe a case of successful laser in situ

More information

LASIK SURGERY OUTCOMES, VOLUME AND RESOURCES

LASIK SURGERY OUTCOMES, VOLUME AND RESOURCES MOH Information Paper: 2006/17 LASIK SURGERY OUTCOMES, VOLUME AND RESOURCES By Dr. Ganga Ganesan 1 I INTRODUCTION LASIK stands for Laser-Assisted In Situ Keratomileusis and is a surgical procedure that

More information

Q-factor customized ablation profile for the correction of myopic astigmatism

Q-factor customized ablation profile for the correction of myopic astigmatism Q-factor customized ablation profile for the correction of myopic astigmatism Tobias Koller Hans Peter Iseli Farhad Hafezi Michael Mrochen Theo Seiler From the Institut für Refraktive und Ophthalmo-Chirurgie

More information

Excimer Laser Eye Surgery

Excimer Laser Eye Surgery Excimer Laser Eye Surgery This booklet contains general information that is not specific to you. If you have any questions after reading this, ask your own physician or health care worker. They know you

More information

Our Commitment To You

Our Commitment To You SYSTEM SUPPORT Quality-crafted, the system boasts dependability with high efficiency and low gas usage. We provide responsive service and maintenance contract options, supported by our nationwide direct

More information

Simple regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation

Simple regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation J CATARACT REFRACT SURG - VOL 32, MARCH 26 Simple regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation Samuel Masket, MD, Seth Everett

More information

How do we use the Galilei for cataract and refractive surgery?

How do we use the Galilei for cataract and refractive surgery? How do we use the Galilei for cataract and refractive surgery? Douglas D. Koch, MD Mariko Shirayama, MD* Li Wang, MD, PhD* Mitchell P. Weikert, MD Cullen Eye Institute Baylor College of Medicine Houston,

More information

Informed Consent for Refractive Lens Exchange (Clear Lens Replacement)

Informed Consent for Refractive Lens Exchange (Clear Lens Replacement) Mark Packer, M.D. Informed Consent for Refractive Lens Exchange (Clear Lens Replacement) This surgery involves the removal of the natural lens of my eye, even though it is not a cataract. The natural lens

More information

Retinal straylight and light distortion phenomena in normal and post-lasik eyes

Retinal straylight and light distortion phenomena in normal and post-lasik eyes DOI 10.1007/s00417-010-1583-7 REFRACTIVE SURGERY Retinal straylight and light distortion phenomena in normal and post-lasik eyes Alejandro Cerviño & Cesar Villa-Collar & Jose Manuel Gonzalez-Meijome &

More information

No-history method of intraocular lens power calculation for cataract surgery after myopic laser in situ keratomileusis

No-history method of intraocular lens power calculation for cataract surgery after myopic laser in situ keratomileusis J CATARACT REFRACT SURG - VOL 33, JANUARY 2007 No-history method of intraocular lens power calculation for cataract surgery after myopic laser in situ keratomileusis H. John Shammas, MD, Maya C. Shammas,

More information

ABLATION-RELATED COMPLICATIONS FOLLOWING

ABLATION-RELATED COMPLICATIONS FOLLOWING Topographically Supported Customized Ablation for the Management of Decentered Laser In Situ Keratomileusis GEORGE D. KYMIONIS, MD, PHD, SOPHIA I. PANAGOPOULOU, BSC, IOANNIS M. ASLANIDES, MD, PHD, SOTIRIS

More information

Straylight values 1 month after laser in situ keratomileusis and photorefractive keratectomy

Straylight values 1 month after laser in situ keratomileusis and photorefractive keratectomy ARTICLE Straylight values 1 month after laser in situ keratomileusis and photorefractive keratectomy Jeroen J.G. Beerthuizen, MD, FEBOphth, Luuk Franssen, MSc, Monika Landesz, MD, PhD, Thomas J.T.P. van

More information

LASIK To Improve Visual Acuity in Adult Neglected Refractive Amblyopic Eyes: Is It Worth?

LASIK To Improve Visual Acuity in Adult Neglected Refractive Amblyopic Eyes: Is It Worth? JKAU: Med. Sci., Vol. 18 No. 4, pp: 29-36 (2011 A.D. / 1432 A.H.) DOI: 10.4197/Med. 18-4.3 LASIK To Improve Visual Acuity in Adult Neglected Refractive Amblyopic Eyes: Is It Worth? Ali M. El-Ghatit, MD,

More information

Consumer s Guide to LASIK

Consumer s Guide to LASIK Consumer s Guide to LASIK A Community Service Project brought to you by Price Vision Group Your Guide To A Successful LASIK Procedure The purpose of this educational guide is to help prospective patients

More information

FIRST EXPERIENCE WITH THE ZEISS FEMTOSECOND SYSTEM IN CONJUNC- TION WITH THE MEL 80 IN THE US

FIRST EXPERIENCE WITH THE ZEISS FEMTOSECOND SYSTEM IN CONJUNC- TION WITH THE MEL 80 IN THE US FIRST EXPERIENCE WITH THE ZEISS FEMTOSECOND SYSTEM IN CONJUNC- TION WITH THE MEL 80 IN THE US JON DISHLER, MD DENVER, COLORADO, USA INTRODUCTION AND STUDY OBJECTIVES This article summarizes the first US

More information

Patient s Guide to Choosing Your Refractive Surgeon

Patient s Guide to Choosing Your Refractive Surgeon Patient s Guide to Choosing Your Refractive Surgeon LASIK & Advanced Vision Correction 100 Meridian Centre, Suite 125, Rochester, NY 14618 There are many things to consider when looking for a doctor to

More information

The Efficacy of Multi-Zone Cross-Cylinder Method for Astigmatism Correction

The Efficacy of Multi-Zone Cross-Cylinder Method for Astigmatism Correction Korean J Ophthalmol Vol. 18:29-34, 2004 The Efficacy of Multi-Zone Cross-Cylinder Method for Astigmatism Correction Seong Joo Shin, MD, Hae Young Lee, MD Department of Ophthalmology, Seoul Adventist Hospital,

More information

Pseudo-accommodative Cornea (PAC) for the Correction of Presbyopia

Pseudo-accommodative Cornea (PAC) for the Correction of Presbyopia Pseudo-accommodative Cornea (PAC) for the Correction of Presbyopia Alaa El Danasoury, FRCS Magrabi Hospitals & Centers Surgical options for the Correction of Presbyopia Monovision Reversal of Presbyopia:

More information

Surgeon offsets and dynamic eye movements in laser refractive surgery

Surgeon offsets and dynamic eye movements in laser refractive surgery J CATARACT REFRACT SURG - VOL 31, NOVEMBER 005 ARTICLES Surgeon offsets and dynamic eye movements in laser refractive surgery Jason Porter, PhD, Geunyoung Yoon, PhD, Scott MacRae, MD, Gang Pan, PhD, Ted

More information

Laser in situ keratomileusis for mixed astigmatism using a modified formula for bitoric ablation

Laser in situ keratomileusis for mixed astigmatism using a modified formula for bitoric ablation European Journal of Ophthalmology / Vol. 18 no. 6, 2008 / pp. 869-876 Laser in situ keratomileusis for mixed astigmatism using a modified formula for bitoric ablation D. DE ORTUETA, C. HAECKER Augenlaserzentrum

More information

Conductive keratoplasty (CK) utilizes radiofrequency energy. Original Article

Conductive keratoplasty (CK) utilizes radiofrequency energy. Original Article Original Article Comparing the Rate of Regression after Conductive Keratoplasty with or without Prior Laser-Assisted in situ Keratomileusis or Photorefractive Keratectomy Majid Moshirfar, Erik Anderson

More information

Visual Quality after Wavefront-Guided LASIK for Myopia

Visual Quality after Wavefront-Guided LASIK for Myopia J Korean Med Sci 2005; 20: 860-5 ISSN 1011-8934 Copyright The Korean cademy of Medical Sciences Visual Quality after Wavefront-Guided LSIK for Myopia This study evaluated the visual quality after wavefront-guided

More information

Quality of Vision After Refractive Surgery

Quality of Vision After Refractive Surgery Quality of Vision After Refractive Surgery 19 Thomas Kohnen, Jens Bühren, Thomas Kasper, Evdoxia Terzi The authors have no proprietary interest in any of the devices used in this study. Core Messages After

More information

Irregular astigmatism:

Irregular astigmatism: Irregular astigmatism: definition, classification, topographic and clinical presentation Ming X. Wang, MD, PhD Clinical Associate Professor of Ophthalmology of University of Tennessee Director, Wang Vision

More information

Consumer s Guide to Choosing Your Refractive Surgeon

Consumer s Guide to Choosing Your Refractive Surgeon Consumer s Guide to Choosing Your Refractive Surgeon Refractive Surgical Center 100 Meridian Centre, Suite 125, Rochester, NY 14618 585-273-2020 www.strongvision.urmc.edu There are many things to consider

More information