Foreword. Richard Troutman, MD, DSc (Hon), FACS, FRCOphth

Transcription

1 Foreword Richard Troutman, MD, DSc (Hon), FACS, FRCOphth I would like to congratulate Dr Gaster for having assembled this comprehensive collection of papers on Recent Advances in Cornea, External Disease and Refractive Surgery for this issue of International Ophthalmology Clinics authored by such outstanding international authorities and thank him for having entrusted me to write this Foreword. Because of my career-long interest in microsurgery of the anterior segment, and in particular cornea and refractive surgery, I have vicariously continued to follow, through my former Fellows, like Dr Gaster and Dr Lawless, both authors in this volume, and by annual attendance at the meetings of the ISRS and The Cornea Society, both of which I am proud to be a Founder, the remarkable evolution of microsurgical corneal and refractive surgery to the current state of the art. On reviewing the papers for this edition of International Ophthalmology Clinics, I am immediately struck by the fact that, when I retired in 1991, most of the techniques and instrumentation had just been introduced or were in the early stages of development or did not yet exist, and that my accustomed procedures have evolved almost beyond recognition. Notwithstanding, I am gratified to see that the operating microscope is still an integral part of our armamentarium, and fellow pioneer Microsurgeons Harms and Mackensen s monofilament nylon, with whom, in 1965, I formed the International Ophthalmic Microsurgery Study Group to promote the universal use of the microscope. I am also pleased to note that surgery for astigmatism, after languishing for many years, has finally come of age, and that my relaxing incisions technique (aka astigmatic keratotomy) has been revived and is being used extensively with femtosecond laser cataract surgery and for woundinduced astigmatism from keratoplasty. INTERNATIONAL OPHTHALMOLOGY CLINICS Volume 53, Number 1, xi xvi r 2013, Lippincott Williams & Wilkins xi

2 xii Troutman I am certain that Jose Barraquer, my friend and mentor, who introduced me to refractive surgery and trusted me to perform the first cases outside of Colombia in 1977 and help him bring it to the world, would be as surprised and delighted as I at the remarkable progress of his baby since he first conceived its basic principles 30 years before in My attraction to anterior segment and cornea surgery began early in my training with my Chief John McLean, whose McLean suture was then the state of the art for cataract surgery, and with R. Townley Paton, a pioneer corneal surgeon and Founder of the New York Eye Bank, but especially with Jose s equally talented younger brother Joaquin, discoverer of a chymotrypsin, who shared my interest in using the microscope for surgery of the anterior segment and introduced me to his advanced techniques and instrumentation. During my practice, most corneas were transplanted in full thickness, penetrating keratoplasty (PK), whether endothelial failure was the primary cause, for example, cornea dystrophies, or when the endothelium was intact, for example, keratoconus. In his paper, Dr Giebel details the current approaches to endothelial failure, selective replacement of endothelium and Descemet s (Melles, 1998) DSEK, DSAEK, and DMEK: DSEK (Descemet s stripping endothelial keratoplasty), DSAEK (A = automated), and DMEK (M = membrane) that significantly reduce postoperative morbidity with minimal or no wound-induced astigmatism. For DSEK, the surgeon removes only the posterior failed endothelium and Descemet s and replaces it with corresponding donor tissue. For DSAEK, the Eye Bank supplies the donor material precut, simplifying the procedure for the surgeon. The more precise DMEK has optically better functional outcomes but has been avoided because it is technically more difficult. Dr Giebel discusses his SCUBA (submerged cornea using backgrounds away) technique, which simplifies the harvesting of the graft, making the procedure more accessible for general use. The chapter by Dr Gaster on a novel insertion technique for the corneal lenticule in DSAEK shows that this straightforward, cost-effective innovation is both efficacious and safe for patients with endothelial disease. He shows that endothelial cell density loss is minimized, whereas best spectacle-corrected visual acuity is improved by this advancement in DSAEK surgery. More DSAEK specialists may well adapt this exciting new technique in the near future as they see its practicality and utility. Three new surgical techniques for the management of keratoconus, formerly only treatable by contact lenses or trephine cut PK, have come into use since my retirement. They are surgical, Intacs, DALK (deep anterior lamellar keratoplasty), and zig-zag patterned femtosecond laser PK, and are described here by Drs Rabinowitz, El Danasoury, and Steinert. Intacs are segmental, semilunar, and interlamellar plastic corneal inserts that selectively flatten and regularize the corneal cone

3 Foreword xiii central to the insert and have been FDA approved since 1999 for the treatment of mild to moderate keratoconus in patients with contact lens intolerance with a minimum corneal thickness of 450 mm. They can improve uncorrected visual acuity and contact lens tolerance, postponing or eliminating the necessity for PK or DALK. The femtosecond laser simplifies the creation of the interlamellar pockets. DALK is used for replacing anterior corneal stromal pathology, leaving normal Descemet s and endothelium intact. Dr El Danasoury describes the big bubble technique (Archila, 1984) for separating endothelium from the stroma before removing and replacing the central pathologic cornea with a lamellar donor stromal graft. Leaving the normal Descemet s and endothelium intact not only promotes earlier healing and recovery of visual function but also significantly reduces or eliminates postoperative endothelial rejection. Dr Steinert discusses his use of the femtosecond laser for PK, primarily when both the endothelium and the stroma are involved in the pathology and now only rarely for keratoconus when DALK is not possible. The laser is used to cut the opposing edges of the graft and recipient with matching zig-zag patterns. Closed with interrupted and running 10-0 nylon suture, the matched apposed edges provide more secure anterior/posterior and circumferential wound apposition than the vertical trephine cut wound profile, promoting first intention healing, reduced postsuture removal wound-induced astigmatism, and earlier rehabilitation than traditional techniques. This technique would seem to be ideally suited for my through and through suture technique (for which I developed the compound curve needle) that ensure full-thickness apposition during healing, avoiding inadvertent suture-induced internal wound gaping from deep intrastromal suture bites. The femtosecond laser zig-zag pattern has the same advantages when used for DALK. With the big bubble technique, the donor stromal graft for the DALK is separated from Descemet s/endothelium at a more defined level, leaving the Descemet s/endothelium intact. This technique brought to mind the square pattern graft, fixed by overlying mattress sutures, which Castroviejo used in the 1940s that he believed promoted faster healing because the corners were closer to the vascular periphery. Dr Gaster reviews corneal cross linking (CXL) (Seiler, 1999), the first nonsurgical treatment, which is being increasingly used in early and progressive keratoconus to delay or avoid surgery. CXL works by photochemically increasing the rigidity of the cornea. Although the long-term results are yet to be determined, according to Dr Gaster, it is one of the most important advances in the management of keratoconus in recent memory. He prefers the epi-off CXL treatment to epi-on CXL, where the corneal epithelium is left intact and acts as a barrier to the riboflavin saturation. In epi-off CXL, the denuded cornea is bathed with a riboflavin solution and then exposed to ultraviolet for 30 minutes. Dr Gaster reports excellent results with epi-off CXL, obviating the need

4 xiv Troutman for PK for many patients with progressive keratoconus or post-lasik ectasia. The new technique that Dr Gaster is pioneering where the excimer laser is used to remove and smooth the epithelial removal has shown excellent early results. Furthermore, his recent report on CXL in teenagers seems very promising and exciting news for young individuals with keratoconus. Dr Hardten discusses the surgical correction of larger amounts of preexisting and surgically or trauma-induced corneal astigmatism, and for lesser amounts during cataract surgery. As he details, limbal relaxing incisions (LRI) are increasingly being combined with femtosecond laser cataract surgery for correction of preexisting congenital or developmental corneal astigmatism. He uses the femtosecond laser for relaxing incisions in the graft [corneal relaxing incisions (CRI)] for post-pk astigmatism and at the limbus (LRI) for surgically or trauma-induced astigmatism. The Correction of Astigmatism is a subject that has been and continues to be a major interest of mine. In the Preface, p. xi, of my 1992 Textbook Corneal Astigmatism: Etiology, Prevention, and Management: CV Mosby Co., p. 506, I state: As we reach for the cornea and refractive surgeon s utopia of eliminating the need for glasses or contact lenses, congenital and developmental astigmatism will continue to demand our attention, especially as they accompany spherical ametropia. I discuss in detail 2 corrective procedures I developed for astigmatism correction: corneal wedge resection, 1970, for higher degrees of post-pk induced corneal astigmatism in which a 90-degree V-shaped partial penetrating excision of the graft scar centered on the flatter meridian and closed with 10-0 nylon sutures corrects the astigmatism by steepening its flatter meridian to sphericity, and CRI (aka astigmatic keratotomy), 1974, for lesser degrees of corneal astigmatism, where 90-degree paired, partial penetrating semilunar corneal incisions centered across the steeper meridian are made in the scar, with PK, or at the limbus (LRI) that flatten the steeper meridian to sphericity. With larger amounts of astigmatism, a sutured, healed corneal wedge resection would have less tendency to drift from delayed stretching of the incisional zone with delayed undercorrection than from stretching of the incisional zones of relaxing incisions (CRI) that can result in delayed overcorrection. Dr Alio describes the use of 3 types of toric phakic IOL s that can be used for correction of higher degrees of simple and compound astigmatism and axial myopia or hyperopia. Fixated in the anterior chamber angle, the pupil, or in the sulcus posterior to the iris and for axial spherical errors, they should be used with caution as they have been reported to cause endothelial failure with the anterior chamber fixation and cataract in or posterior to the pupil. The chapter on LASIK by Dr Lawless, my former Fellow, is of great nostalgic interest to me. I can hardly believe that it has been 35 years

5 Foreword xv since Cas Swinger, my Fellow at the time, and I performed the first case of keratophakia in the United States. As Drs Gaster and Lawless, who closely followed, can testify that, the surgery and instrumentation, in particular the cryolathe, were so complex, that at the time, only a few fellow corneal surgeons were interested in attempting it. In fact, Dr Gaster actually performed several keratophakia procedures in the early 1980s, with gratifying results. Eclipsed by radial keratotomy (RK) (Fyodorov), a much simpler technique that would, however, turn out to be fatally flawed, Barraquer s techniques for refractive surgery almost disappeared. Then, in 1983, Trokel and Srinivasan introduced the excimer laser that would considerably improve the accuracy and simplify its technical performance, and in 1989, McDonald and Kaufmann performed the first excimer laser refractive cases. It took 10 more years for it to be approved by the FDA. Today, LASIK is the most commonly performed ophthalmic surgery worldwide. Dr Lawless shows that even the uniformly excellent results obtained by the traditional technique have been improved with the advent of the femtosecond laser to create the flap, which is more accurate, thinner, and more regular, and when combined with the Allegretto excimer laser, often results in 20/15 visual acuity. It is difficult to see how much more this technique can be improved. Dr Waring reviews the treatment of presbyopia. The refractive surgical correction of presbyopia that was only a dream when I retired is now a reality with not 1 but several techniques from which the patient can choose. Except for presbyopia-correcting advanced technology intraocular lenses, the only approved FDA procedure is monovision, where the nondominant eye is given a myopic correction, refocusing it for near vision. In multifocal LASIK (presbylasik), currently under investigation, the excimer laser is used to create multiple concentric rings that alter the contour of the cornea to create different power zones for seeing at varying distances while allowing both eyes to maintain good distance acuity. The simplest of the newer procedures would seem to be the AcuFocus, a multiple pinhole intracorneal ultra-thin insert that can be readily placed in a femtosecond laser pocket in the anterior stroma at the apex of the cornea. Because of the change in corneal power in eyes that have undergone previous refractive surgery, the calculation of IOL power for the correction of aphakia is complicated, whether by laser vision correction (LVC) or by RK, both requiring different calculations. For post-lvc, the net corneal power, determined by the measurement of anterior and posterior corneal curvatures, is the important variable. In post-rk eyes, the true corneal power can only be estimated by taking into account the small effective optical zone and postoperative hyperopic shift. Dr Tratter discusses the use of these variables to determine the IOL lens power. Another option is the Optiwave Refractive Analysis. Attached to the

6 xvi Troutman objective of the operating microscope, it takes the measurement and calculates the IOL power intraoperatively after the lens has been removed. However, in its current form, it is slightly bulky and cumbersome, occasionally causing instrument contamination and decreasing the range of view of the surgeon. Furthermore, a range of lenses including the determined power has to be available for immediate insertion. Nothing ruins a cornea refractive surgeon s day more than an infectious keratitis! Dr Asbell discusses the latest management and treatment options for methicillin-resistant Staphylococcus aureus, the most common organism cultured in postrefractive surgery keratitis. Recent studies have shown that Trimethoprim is the only agent with high activity against it. When in doubt, careful preoperative evaluation with cultures can prevent postoperative surprises. The same is true for contact lens wearers, especially if they have been using Renu with MoisturLoc or MoisturePlus that have infected eyes with fusarium or acanthamoeba. She reviews the use of corticosteroids with antibiotics for acute bacterial keratitis and ulcers and concludes that adjunctive steroids neither improve nor deteriorate the treatment for bacterial corneal ulcers. The most exciting new addition to the management of infectious keratitis is the use of CXL with riboflavin and UV-A, which can stabilize thinning of the cornea, arrest corneal melting, and promote epithelialization. She also discusses the use of Gancyclovir, recently approved for the treatment of herpes simplex keratitis, which may also be effective against adenovirus that has previously been limited to symptomatic treatment. My only wish, after completing this review, is that I could turn back the clock, return to the operating room, and under the guidance of the authors, and especially Drs Gaster and Lawless, perform the procedures described. I can only imagine what the next decades will bring, but, rest assured, I will be watching and learning from wherever I may be. The author declares that there is no conflicts of interest to disclose.