Year : 2014 | Volume
: 21 | Issue : 1 | Page : 1--2
Refractive surgery: The never-ending task of improving vision correction
Samar A Al-Swailem
Anterior Segment Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
Samar A Al-Swailem
Anterior Segment Division, King Khaled Eye Specialist Hospital, 7191, Riyadh 11462, Riyadh
|How to cite this article:|
Al-Swailem SA. Refractive surgery: The never-ending task of improving vision correction.Middle East Afr J Ophthalmol 2014;21:1-2
|How to cite this URL:|
Al-Swailem SA. Refractive surgery: The never-ending task of improving vision correction. Middle East Afr J Ophthalmol [serial online] 2014 [cited 2020 Aug 13 ];21:1-2
Available from: http://www.meajo.org/text.asp?2014/21/1/1/124075
It is an honor to be part of the editorial board, and to write this editorial for this theme-based issue of the Middle East African Journal of Ophthalmology. It is my belief that the advances, enthusiasm, and anticipation in the fast growing subspecialty of refractive surgery remain unrivaled in ophthalmology. Additionally, the rapid advances from scientific research and technology have increased the safety, accuracy, and predictability of altering the refractive error of the human eye in the twenty-first century. Currently, the European market is several years ahead of the United States, Middle East and Africa because refractive techniques are introduced and technology is available prior to the other continents. Therefore, the European market may provide a greater insight into the future of refractive surgery.  In this issue, refractive surgery experts from different continents in refractive surgery have undertaken an important service for the Middle East African Journal of Ophthalmology readers by providing current updates of technologies and state-of-art surgical techniques.
Historically, the cornea has been the focal point of the refractive surgeons due to the anatomical accessibility. Incisional surgery to correct astigmatism was initially proposed in 1885 by the Scandinavian ophthalmologist Schiotz. It was not until the late 1930s that Sato published article on how corneal hydrops would cause loss of myopia because of the induced corneal flattening.  In this issue of the Middle East African Journal of Ophthalmology, Al-Mahmood and Al-Swailem from Saudi Arabia provide a comprehensive review of suturless clear corneal incision in modern-cataract surgery. Some advantages of corneal incision over scleral incisions include lower induced astigmatism, minimal induced astigmatism when performing temporal incisions, tailoring incision location to reduce pre-existing astigmatism and faster visual recovery. Authors describe the best wound and blade design to achieve a water-tight wound.
Additional work by the godfather of modern refractive surgery (Jose Ignacio Barraquer) in the 1940s described subtraction corneal stromal surgery (keratomileusis) to induce corneal remodeling. Subsequently, a group of Russian ophthalmologists in the early 1970s (Durnev and Fyodorov) proposed the first controlled external radial corneal incisions in an attempt to modify myopia. It was not until late 1983 that Steven Trokel published the first article on the use of a 193 nm excimer laser to make precision radial cuts and removal of corneal stroma.  Excimer laser refractive surgery (LRS) became one of the most common surgeries worldwide.  Dawoud and Stark from Baltimore review LRS in systemic and autoimmune disease. They discuss the spectrum of diseases and conditions such as collagen vascular disease, diabetes mellitus, allergic and atopic disease, HIV, pregnancy and dermatologic keloid formation. They underscore the importance of selecting patients with mild, well-controlled disease, discussing the risks and benefits of each LRS option with the patients, and obtaining a detailed consent form.
In 1987, Simon first placed corneal silicone rings. As more biocompatible materials were developed, it is currently possible to place intrastromal corneal ring segments (ICRS) at two thirds of the corneal depth. The aim of ICRS surgery is to induce geometric change in the central curvature, thus improving the visual acuity, and reducing the refractive error and mean keratometry. Additionally, this promising surgical alternative to LRS is a good option for patients who do not want permanent corneal changes.  In this issue, Alio and co-authors from Spain evaluate the outcome of ICRS implantation in keratoconic eyes with 5-years follow-up, based on a new grading system which accounts for the patient's preoperative visual impairment, rather than keratometric readings. Eyes with milder form of keratoconus (KC) and greatest levels of corrected distant visual acuity (CDVA), preoperatively, are the ones with the greatest loss of CDVA after ICRS surgery. Furthermore, these authors found that in contrast to the stable KC cases, a significant reduction of both CDVA and uncorrected distant visual acuity (UDVA), 6 months following ICRS implantation, is observed in the progressive KC cases.
Presbyopia is a ubiquitous visual disability of the aging eye, affecting an estimated 1.04 million people globally.  Its pathophysiology still remains poorly understood and there are currently two prevailing theories (Helmholtz and Schachar), which may not fully address the development of presbyopia.  Although still far from optimal, techniques for treating presbyopia have developed form these theories. Pandalis from Greece provides an excellent comprehensive over review of surgical techniques and related devices currently in use or in development for the treatment of presbyopia. He includes PresbyLASIK, presbyopic femtosecond laser ablation (Intracor), corneal inlays, presbyopic-correcting intraocular lenses, and scleral procedures. The author stresses the importance of patient selection and appropriate procedure selection for a good outcome.
Following the introduction of the first biologically inert intraocular lens (IOL) by Harold Ridley in 1952, cataract surgery has evolved to a refractive procedure, in which ophthalmologists attempted to correct all or most of the refractive error including presbyopia.  Furthermore, field of premium IOLs is changing rapidly. The current choices include multifocal and accommodating IOLs. The initial clinical results of a novel multifocal IOL with gradient refractive index optics (Gradiol) is described in this issue by Malyugin from Russia. His prospective study reports subjective (using VF-14 questionnaire) testing, optical disturbances, and visual acuity with six-month follow-up in 29 eyes.
Equally important is the need for more refractive studies in this region of the world, including large multicenter controlled clinical trials as well as genetic studies to discover the genes responsible for myopia, hyperopia, and astigmatism. Finally, the entire editorial staff and I pledge to endeavor to advance the level of your journal with this refractive issue and to create a product of great pride for all members of the Middle East Africa Council of Ophthalmology (MEACO).
|1||Lindstrom RL. Maller BS. Market trends in refractive surgery. J Cataract Refract Surg 1999;25:1408-11.|
|2||Linebarger EJ, Lindstrom RL, Hardten DR, Chu YR. Refractive surgery in the new millennium. Ophthalmol Clin North Am 2001;14:377-88.|
|3||O'Doherty M, O'Keeffe M, Kelleher C. Five year follow up of laser in situ keratomileusis for all levels of myopia. Br J Ophthalmol 2006;90:20-3.|
|4||Pinero DP, Alio JL. Intracorneal ring segments in ectatic corneal disease: A review. Clin Experiment Ophthalmol 2010;38:154-67.|
|5||Holden BA, Frick TR, Ho SM, Wong R, Schlenther G, Cronjé S, et al. Global vision impairment due to uncorrected presbyopia. Arch Ophthalmol 2008;126:1731-9.|
|6||Schachar RA. Cause and treatment of presbyopia with a method for increasing the amplitude of accommodation. Ann Ophthalmol 1992;24:445-7.|