EXAMINATION OF CORNEAL DYSTROPHIES

Transcription

1 Doctoral School of Semmelweis University, Division of Clinical Sciences, Programme of Ophthalmology Programme leader: Ildikó Süveges M.D. Ph.D. D.Sc. Project leader: Ildikó Süveges M.D. Ph.D. D.Sc. EXAMINATION OF CORNEAL DYSTROPHIES Ph D. Thesis Nóra Szentmáry M.D. Semmelweis University, Faculty of Medicine 1 st Department of Ophthalmology Budapest, 2005

2 INTRODUCTION The cornea is the first refractive tissue through which light passes on entering the eye. Loss of transparency of the highly refractive cornea, or irregularity of its surface, both result in severe impairment of visual function. Amongst the various processes which may result in loss of transparency of the cornea, I here present results of examinations concerning corneal dystrophies, which were the object of our scientific research. In these rare noninflammatory disorders, which are almost invariably inherited, metabolically generated material is gradually deposited in the cornea, and this causes progressive loss of visual acuity. At present, neither the pathomechanism nor the cause of the development of these corneal dystrophies is understood in detail. If the cornea loses its transparency, corneal transplantation may allow the patient to regain good visual acuity. Today, corneal transplantation is the most successful type of tissue transplantation; although it nevertheless still has its risks. During the last few years the indications for such penetrating keratoplasty (PK) have changed, reflecting developments in alternative treatment methods for corneal pathologies, and in techniques of intraocular surgery. Excimer laser treatment is a recent innovation in the treatment of corneal disease; excimer laser treatments for refractive adjustment and for therapeutic purposes started in the 1980s. The advantage of such phototherapeutic keratectomy (PTK) is that improvement of visual function in corneal disease can be achieved much less invasively than is the case with penetrating keratoplasty. With PTK, the laser beam removes only the most 2

3 superficial layer of the corneal tissue, which is often the part which is diseased or non-transparent. In our scientific investigations our aim was to examine corneal dystrophy patients with regard to the specific aims described in the following section. 3

4 SPECIFIC AIMS 1. To analyse trends in the indications for penetrating keratoplasty (PK) during the last 11 years ( ) at our clinic (1 st Department of Ophthalmology, Semmelweis University, Budapest). In particular, to determine the percentage of corneal dystrophy patients who underwent penetrating keratoplasty, and to compare our results with those reported in other countries. 2. In patients at our clinic with stromal corneal dystrophies, to determine the outcome of primary penetrating keratoplasties (PK), and to compare the results with the outcome of primary phototherapeutic keratectomies (PTK). 3. To examine the impact of previous phototherapeutic keratectomy (PTK) on the outcome of subsequent penetrating keratoplasty (PK), in patients with stromal corneal dystrophies (Friedrich-Alexander University, Erlangen, Germany). 4. To determine the outcome of excimer laser phototherapeutic keratectomy (PTK) for lattice corneal dystrophy; either as a primary procedure, or following penetrating keratoplasty (1 st Department of Ophthalmology, Semmelweis University). 5. To evaluate the role of corneal cell proliferation and apoptosis in the pathogenesis of granular, macular and lattice dystrophies. 6. To elucidate the pathomechanism of Fuchs' dystrophy and pseudophakic bullous keratopathy (PBK) by examining cell apoptosis in different corneal layers. 4

5 METHODS 1. Retrospective analysis of histological diagnoses of 1274 corneal buttons of patients who underwent PK at the 1 st Department of Ophthalmology of Semmelweis University between January 1992 and December In determining the diagnosis the priority scheme of Mamalis et al. was used. 2. Inclusion criteria for patients following PK in our retrospective study (total: 11 eyes of 7 patients) were: (1.) PK performed between January 1992 and January 2004; (2.) Histological diagnosis of samples from cases of granular, macular, or lattice corneal dystrophy (1 eye, 5 eyes, 5 eyes, respectively); (3.) Procedures performed by one experienced surgeon. Best corrected visual acuity (BCVA), spherical equivalent (SEQ) and refractive cylinder (Canon, auto ref-keratometer RK-3) parameters were determined before keratoplasty, and before and after suture removal. Results were compared to the outcome of previously published results of primary PTK treatments of eyes with granular dystrophy (1 eye) and lattice dystrophy (2 eyes of 1 patient, see item No. 4). 3. Retrospective clinical study at the Department of Ophthalmology of Friedrich-Alexander University. Patient population (study group and controls): 15 patients (21 eyes) age 39.9? 11.4 years. Inclusion criteria: (1.) Primary homologous PK performed in phakic patients with granular or macular dystrophy; (2.) No use of combined surgical procedures; (3.) Defined graft size and technique. The study group comprised 8 eyes of 5 patients; PK had been performed 3.7? 2.3 years after PTK. The control 5

6 group (no previous PTK) comprised 13 eyes of 10 patients. In both groups, 38% had granular and 62% had macular dystrophy. Intervention procedures: PTK was performed using a 193nm excimer laser. All PKs were also performed using this laser, with trephination using a metal mask. Subjective refractometry (trial lenses), standard keratometry (Zeiss ophthalmometer) and corneal topography (Tomey TMS-1) were performed preoperatively, 6 months after PK, and after first and second suture removal (1.1? 0.2 years and 1.6? 0.2 years, respectively). Main outcome measures: astigmatism (keratometric, topographic net astigmatism, refractive cylinder); keratometric and topographic central power; best corrected visual acuity (BCVA); topographic parameters: surface regularity, surface asymmetry indices (SRI, SAI), potential visual acuity (PVA). 4. Four eyes of two patients who underwent excimer PTK for recurrent erosions and reduced vision due to lattice dystrophy, between October 1998 and May 2001, were reviewed. Two eyes (one patient) underwent penetrating keratoplasty 15 years before PTK; while in two eyes PTK was the primary procedure. Data regarding the preoperative and postoperative best-corrected visual acuity, change in spherical equivalent, refraction, symptomatic relief, and incidence of recurrence were analysed by a retrospective review of patient records. 5. The study group comprised 39 eyes (of 33 patients) which had undergone penetrating keratoplasty (PK) for stromal dystrophies: these comprised 12 eyes (of 9 patients, 55.5% males) with granular dystrophy, 13 eyes (12 patients, 33.3% males) with macular dystrophy, and 14 eyes (13 patients, 61.5% males) with lattice type I dystrophy. A further 4 6

7 corneal buttons from enucleated eyes of 4 patients with choroideal melanoma served as controls. Immunocytochemical analysis of Ki67 (DNAcon Kit, DakoCytomation A/S, Glostrup, Denmark) was used for evaluation of cell proliferation. Apoptosis was detected by use of the TUNEL (terminal deoxyribonucleotidyl transferase-mediated dutpdigoxigenin nick-end labelling) assay method (Apoptag reagent, Q- Biogene, Strasbourg, France). Statistical comparisons were made using the Mann-Whitney test. 6. We studied corneal buttons obtained from 21 eyes following central penetrating keratoplasty: 14 corneal buttons (13 patients, age 70.8 ± 10.0 years) with Fuchs' dystrophy, and 7 buttons (7 patients, age 69.6 ± 10.2 years) with PBK. 4 buttons from enucleated eyes with choroidal melanoma served as controls. Histological changes were examined using light microscopy with haematoxylin-eosin (HE) staining. The average numbers of apoptotic cells per field of view (125x magnification) in separate samples of the epithelial, stromal and endothelial layers were determined using the TUNEL assay. 7

8 RESULTS, CONCLUSIONS 1. In agreement with studies performed in the United States, Canada and Denmark, in our clinic the most frequent indication for PK was pseudophakic/aphakic bullous keratopathy. Histological diagnoses were pseudophakic/aphakic corneal oedema (43.4%), regraft (14.2%), ulcer/keratitis (14.2%), keratoconus (9.4%), corneal scars (8.8%), Fuchs dystrophy (5.7%) and corneal dystrophies (2.0%). The incidence of Fuchs and other corneal dytsrophies was similar to those reported in other countries, and did not show changes with time. 2. During follow-up of PKs (9.5? 3.2 months) there was suture loosening in one eye, but inflammation or haze did not develop in donor corneas. Following suture removal, compared to preoperative values the mean BCVA value improved significantly (preop/postop: 0.3? 0.1/0.8? 0.1; p = 0.01); the mean SEQ value did not show significant difference (-1.6? 3.3/-1.5? 1.5; p = 0.7); and there was a non-significant increase in the refractive cylinder mean value (-0.2? 1.4/-3.5? 2.3; p = 0.1). In stromal corneal dystrophies PK is a safe procedure in impovement of visual acuity without early complications. PK may even provide 1.0 visual acuity for the patients, which is better than PTK treatments usually achieve. 3. We did not find any difference in the outcome of the penetrating keratoplasty, in respect of whether or not there had been a preceding PTK treatment. Following penetrating keratoplasty, none of the 8

9 measured parameters (keratometric, topographic net astigmatism and refractive cylinder; keratometric and topographic central power; best corrected visual acuity (BCVA); surface regularity, surface asymmetry indices (SRI, SAI), potential visual acuity (PVA)) differed significantly between the two groups, at any time-point. Thus, a preceding PTK treatment does not appear to impair the outcome of subsequent penetrating keratoplasty in stromal corneal dystrophy patients. 4. During the follow-up period (20-63 months), all eyes with lattice dystrophy showed improved BCVA; in two cases a slight hyperopic shift was found. All patients were free of symptoms of recurrent erosions and there were no major complications. Thus, as has also been shown in previous studies, we found that in patients with lattice dystrophy excimer PTK is a safe and effective procedure for relieving symptoms of recurrent erosions and improving visual acuity. 5. No Ki67-positive cells were detected in the stromal dystrophy patients. Compared to the controls, in granular and lattice type I dystrophies there was an increase of the mean (normalised) apoptotic keratocyte number, but this was non-significant (p = 0.36, 0.63 respectively); the difference was statistically significant only for macular dystrophy (p = 0.01). Keratocyte apoptosis seems to be a concomitant or pathogenic factor in macular dystrophy. However, the pathways that are triggered to result in increased apoptotic cell death remain to be clarified. 9

10 6. Compared to the controls there was a statistically significant difference in the mean (normalised) apoptotic cell numbers for all 3 layers (p=0.01 in each case) in the Fuchs' dystrophy corneas, and for the stromal layer (p<0.01) in PBK corneas. The apoptotic cell numbers for the epithelial and endothelial layers of the latter were higher, but the difference was not statistically significant (p=0.07, 0.07 respectively). Apoptosis may play a role in the pathomechanism of Fuchs dystrophy and in keratocyte death in corneas with PBK. However, the molecular genetic background and the pathways that are triggered to result in increased apoptotic cell death remain to be clarified. 10

11 NEW RESULTS 1. In agreement with studies performed in the United States, Canada and Denmark, in our clinic the most frequent indication for PK was pseudophakic/aphakic bullous keratopathy. The incidence of Fuchs and other corneal dytsrophies was similar to those reported in other countries, and did not show changes with time. 2. In stromal corneal dystrophies PK is a safe procedure in impovement of visual acuity without early complications. PK may even provide 1.0 visual acuity for the patients, which is better than PTK treatments usually achieve. 3. Preceding PTK treatment does not appear to impair the outcome of subsequent penetrating keratoplasty in stromal corneal dystrophy patients. 4. Excimer PTK was a safe and effective procedure at our clinic for relieving symptoms of recurrent erosions and improving visual acuity in patients with lattice dystrophy No Ki67-positive cells were detected in the stromal dystrophy patients. In granular and lattice type I dystrophies there was an increase of the mean (normalised) apoptotic keratocyte number, which was related to the progression of the dystrophies. In macular and Fuchs dystrophy keratocyte apoptosis seems to be a concomitant or pathogenic factor. However, the pathways that are 11

12 triggered to result in increased apoptotic cell death remain to be clarified. 12

13 LIST OF PUBLICATIONS Related publications 1. Szentmáry N, Langenbucher A, Hafner A, Seitz B. Impact of phototherapeutic keratectomy on the outcome of subsequent penetrating keratoplasty in patients with stromal corneal dystrophies. Am J Ophthalmol 2004; 137: IF: Szentmáry N, Szende B, Süveges I. Epithelial cell, keratocyte and endothelial cell apoptosis in Fuchs dystrophy and in pseudophakic bullous keratopathy. Eur J Ophthalmol; in press. IF: Szentmáry N, Bausz M, Tóth J, Süveges I.?Eleven years of corneal transplantation ( ) at the Semmelweis University 1 st Department of Ophthalmology?. (Hungarian) Szemészet 2004; 141: Szentmáry N, Nagy ZZ, Süveges I.? Phototherapeutic keratectomy (PTK) in type I. Haab-Dimmer dystrophy.? (Hungarian) Szemészet 2004; in press. 13

14 Other publications 1. Szentmáry N, Resch M, Nagy ZZ, Szende B, Süveges I.?Apoptosis in the cornea following photorefractive keratectomy.? (Hungarian) Szemészet 2003; 140: Resch M, Szentmáry N, Nagy ZZ, Czumbel N.?Comparison of results of photorefractive keratectomy and Laser in situ keratomileusis in the treatment of hyperopia using a flying spot excimer laser.? (Hungarian) Orvosi Hetilap 2004; 145; Szentmáry N, Kraszni M, Nagy ZZ. Interaction of indomethacin and ciprofloxacin in the cornea following phototherapeutic keratectomy. Graefe s Arch Clin Exp Ophthalmol 2004; 242 (7): IF: Resch M, Nagy ZZ, Szentmáry N, Máthé M, Kovalszky I, Süveges I.?Glucosaminoglican and keratan sulfate: their spatial distribution and role in the wound-healing of the cornea following photorefractive keratectomy, in the rabbit.? (Hungarian) Szemészet 2004; 141: Resch M, Nagy ZZ, Szentmáry N, Máthé M, Kovalszky I, Süveges I. Spatial distribution of keratan sulfate in the rabbit cornea following photorefractive keratectomy (PRK). J Refr Surg 2004 November; in press. IF: Szentmáry N, Seitz B, Langenbucher A, Naumann GOH. Repeat keratoplasty for correction of high or irregular postkeratoplasty astigmatism in clear corneal grafts. Am J Ophthalmol 2004 November; in press. IF:

15 Citable abstracts 1. Szentmáry N, Resch M, Nagy ZZ, Szende B, Süveges I. Apoptosis in the cornea following photorefractive keratectomy. Der Ophthalmologe 2002; 99 (suppl 1): Resch M, Szentmáry N, Nagy ZZ, Szende B, Süveges I. Histological examination on rabbit corneas following photorefractive keratectomy (PRK). Der Ophthalmologe 2002; 99 (suppl 1): Szentmáry N, Nagy ZZ, Süveges I. Interaction of indomethacin and ciprofloxacin in the cornea following phototherapeutic keratectomy. Der Ophthalmologe 2003; (suppl 1): P182. PRESENTATIONS 1. Szentmáry N, Resch M, Nagy ZZ, Szende B, Süveges I.?Apoptosis in the cornea following photorefractive keratectomy.? (Hungarian) 2002 August; Meeting of the Hungarian Ophthalmological Society, Miskolc. 2. Resch M, Szentmáry N, Nagy ZZ, Szende B, Süveges I.?Histological impact of photorefractive keratectomy on rabbit corneas.? (Hungarian) 2002 August; Meeting of the Hungarian Ophthalmological Society, Miskolc. 15

16 3. Szentmáry N, Resch M, Nagy ZZ, Szende B, Süveges I. Apoptosis in the cornea following photorefractive keratectomy September; DOG, Berlin. 4. Resch M, Szentmáry N, Nagy ZZ, Szende B, Süveges I. Histological examination on rabbit corneas following photorefractive keratectomy (PRK) September; DOG, Berlin. 5. Szentmáry N, Nagy ZZ, Resch M, Süveges I. Phototherapeutic keratectomy (PTK) in Haab-Dimmer dystrophy June; SOE, Madrid. 6. Resch M, Nagy ZZ, Szentmáry N, Süveges I. Ultrasound pachymetric evaluation of corneal stroma and flap edema in myopic LASIK June; SOE, Madrid. 7. Szentmáry N, Szende B, Süveges I.?Apoptosis in the cornea in Fuchs dytsrophy.? (Hungarian) 2003 August; Meeting of the Hungarian Ophthalmological Society, Budapest. 8. Szentmáry N, Nagy ZZ, Süveges I. Interaction of indomethacin and ciprofloxacin in the cornea following phototherapeutic keratectomy September; DOG, Berlin. 9. Szentmáry N, Nagy ZZ, Resch M, Szende B, Süveges I.?Apoptosis in corneal processes.? (Hungarian) 2004 February; Science Day of the Hungarian Ophthalmological Society, Budapest. 16

17 10. Szentmáry N, Szende B, Süveges I.?Apoptosis in the cornea i Fuchs dytsrophy.? (Hungarian) 2004 April;?Semmelweis University, Ph.D Science Days?, Budapest. 11. Szentmáry N, Nagy ZZ, Süveges I: Phototherapeutic keratectomy (PTK) in type I. Haab-Dimmer dystrophy September; DOG, Berlin. 12. Szentmáry N, Papp A, Süveges I: Blickdiagnose - Consilium diagnosticum September; DOG, Berlin. 13. Papp A, Szentmáry N, Domsa P, Módis L, Süveges I:?Case report? (German) Consilium diagnosticum September; DOG, Berlin. 14. Resch M, Nagy ZZ, Szentmáry N, Máthé M, Kovalszky I, Süveges I: Correlation of post-prk inflammation and keratan-sulfate distribution in the rabbit cornea September; DOG, Berlin. 15. Nagy ZZ, Szabó V, Szentmáry N, Resch M: Comparison of hyperopic refractive treatments with different types of excimer lasers and different surgical techniques October; AAO-SOE; New Orleans. 17