Yaron S Rabinowitz1. 1. Ophthalmology Research, Cedars-Sinai Medical Center and Department of Ophthalmology, UCLA School of Medicine, Los Angeles, California 90048, USA. rabinowitzy@cshs.org
Abstract
PURPOSE OF REVIEW: The potential for litigation has resulted in increased interest in ectasia after laser in situ keratomileusis. This article summarizes papers written during this past year on this subject. RECENT FINDINGS: A panel of refractive surgery experts have summarized the current state of knowledge on this subject and provided guidelines to minimize risk. Because ectasia may occur in the absence of risk factors, there may be corneas with biomechanical factors not detectable with present technology which are at risk. Several articles point out the limitations of the Orbscan (Bausch & Lomb, Rochester, New York, USA), in particular its accuracy and reproducibility with regard to data generated from the posterior surface of the cornea. A biomechanical model of the cornea is proposed which suggests that each cornea's response to laser in situ keratomileusis is unique. Several case reports are also reviewed which provide insight into pathogenesis and potential new treatment options; these include reports on histopathology, topographic pseudokeratectasia, ectasia from transient raised intraocular pressure, poor response to laser in situ keratomileusis after incisional surgery, intracorneal rings, collagen cross-linking and conductive keratoplasty to stabilize and sphericize the cornea with ectasia. SUMMARY: Our knowledge about ectasia is still in evolution. Insights into the biomechanics and genetics of the cornea may allow us to further reduce its occurrence.
PURPOSE OF REVIEW: The potential for litigation has resulted in increased interest in ectasia after laser in situ keratomileusis. This article summarizes papers written during this past year on this subject. RECENT FINDINGS: A panel of refractive surgery experts have summarized the current state of knowledge on this subject and provided guidelines to minimize risk. Because ectasia may occur in the absence of risk factors, there may be corneas with biomechanical factors not detectable with present technology which are at risk. Several articles point out the limitations of the Orbscan (Bausch & Lomb, Rochester, New York, USA), in particular its accuracy and reproducibility with regard to data generated from the posterior surface of the cornea. A biomechanical model of the cornea is proposed which suggests that each cornea's response to laser in situ keratomileusis is unique. Several case reports are also reviewed which provide insight into pathogenesis and potential new treatment options; these include reports on histopathology, topographic pseudokeratectasia, ectasia from transient raised intraocular pressure, poor response to laser in situ keratomileusis after incisional surgery, intracorneal rings, collagen cross-linking and conductive keratoplasty to stabilize and sphericize the cornea with ectasia. SUMMARY: Our knowledge about ectasia is still in evolution. Insights into the biomechanics and genetics of the cornea may allow us to further reduce its occurrence.