Eyeworld

EW NEWS & OPINION 18 Dr. Pan, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, dis- cusses the latest evidence suggesting cataract sur- gery does not worsen AMD C ataract and age-related macular degeneration (AMD) are leading causes of visual impairment in elderly people worldwide. Since the earliest case series claimed post-op exacerbation of AMD in 1979, several studies have been con- ducted to confirm whether or not cataract surgery accelerates the pro- gression of AMD. 1 However, the re- sults have been inconclusive and controversial, with most trials suffer- ing from pronounced methodologi- cal deficiencies. 2-4 Ophthalmologists are still puzzled about whether or not cataract surgery increases a pa- tient's risk for choroidal neovascular- ization (CNV), which is the primary symptom of neovascular AMD and predicts progressive loss of vision. Recent studies show no link More recently, a growing number of well-designed studies, including the Age-Related Eye Disease Study (AREDS) 3 and a prospective study 6 conducted by Wilmer Eye Institute at Johns Hopkins University School of Medicine, have presented persua- sive data suggesting no association between cataract surgery and pro- gression of AMD. 3, 5-11 Theoretically, in individuals with AMD and cataract, both dis- eases contribute to the patient's vi- sual disability. It is therefore logical to conclude that visual function im- proves after cataracts are removed and that the benefits increase as the severity of cataract increases. Capturing the macula One of the advantages of the most recent well-designed studies was that the macula was closely examined and photographed before and after the cataract surgery. Reports of in- creasing progression of AMD after cataract surgery could be unreliable without pre-op and post-op fluores- cein angiography or retinal photo- graph to rule out pre-existing CNV or geographic atrophy. 6,9 Since it is difficult for clinicians to see the macula through a cataract-clouded lens, AMD patients with cataracts are challenging to diagnose. Subtle signs of CNV or geographic atrophy may be obscured by lens opacity prior to cataract surgery, and the doctor might ascribe the poor vision to cataract and remove it only later to find AMD in the retina. Unrecog- nized CNV or geographic atrophy can also mislead ophthalmologists to overestimate vision potential after cataract surgery. If ophthalmologists are not fairly certain to what extent the retina might be contributing to vi- sual acuity loss, they should obtain a pre-op fluorescein angiogram or op- tical coherence tomography (OCT) to evaluate the retina before under- taking cataract surgery, particularly in those patients with wet AMD in the fellow eye. It should be noted that although OCT might be able to identify pathology, the growth or fluorescein leakage of CNV could be present even in the absence of ab- normalities on OCT. 12 It is also important for ophthal- mologists and patients to know that even if the fluorescein angiogram or OCT show no retinal abnormalities of relevance to the cataract surgery decision-making process, unrecog- nized retinal disease, which could limit the visual potential of cataract surgery, might still be present. The effect of better techniques It is reasonable to suggest that differ- ent surgery techniques produce dif- ferent effects on macular CNV. 3-14, 15-18 Phacoemulsification has been the mainstream treatment for cataract surgery since the early 1990s. Prior to this, conventional extracapsular cataract extraction (ECCE) or intracapsular cataract ex- traction (ICCE) were the major pro- cedures for cataract removal. Due to September 2011 by Qing Pan, M.D., Ph.D., and Walter J. Stark, M.D. Cataract surgery–macular degeneration: Reduced visual potential, unrecognized choroidal neovascularization rePlay online content P atients with cataracts and potentially vision-limiting ocular comorbidities, such as macular degeneration, usually want to know if their vision will improve if they undergo cataract surgery. Most of them are also looking for reassurance that their macular disease will not take a sudden change for the worse. The issue is not whether their disease will progress—that's the natural his- tory—but whether the rate or slope of the deterioration will change. In this column, Qing Pan, M.D., Ph.D., Walter J. Stark, M.D., and Neil Bressler, M.D., take a critical look at evidence from recent studies and offer some encouragement. Kevin Miller, M.D., challenging cases editor Example of no choroidal neovascularization (CNV) identified at baseline before cataract surgery, with CNV identified at week 1 post-op. The top row shows a hazy color fundus photograph (A) and late-phase fluorescein angiogram (B) identified as showing no definitive CNV, with abnormalities judged to be from drusen and retinal pigment epithelial abnormalities caused by age-related macular degeneration. The second row shows no obvious CNV on color fundus photographs 1 week after cataract surgery (C), but the late-phase fluorescein angiogram frame (D) was interpreted as having fluorescein leakage from CNV along the inferior portion of the macula, with additional speckled fluorescence temporal and inferior to this leakage interpreted as late leakage of an undetermined source Source: Dong LM, Stark WJ, Jefferys JL, Al-Hazzaa S, Bressler SB, Solomon SD, et al. Progression of age-related macular degeneration after cataract surgery. Arch Ophthalmol. 2009;127(11):1412-9

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