Articles about Eye Health and Disease from 2005


Cataract Surgery May Not Increase the Risk of Converting from Dry Age-related Macular Degeneration to Wet Age-related Macular Degeneration


(From Brunner S., M.D., Cataract surgery in nonexudative age-related macular degeneration: first results of a prospective, randomized, multicenter trial, Paper presented at: Annual Meeting of the Association for Research in Vision and Ophthalmology; May 3, 2005)


Preliminary results of a European study suggest that cataract surgery may be safe for patients with confirmed dry age-related macular degeneration (AMD), resulting in improved visual function without AMD progression.  There has been some controversy in the past that cataract surgery might worsen AMD, or cause the disease to progress more rapidly.  Dry AMD is common in older individuals, and is characterized by a slowly developing atrophy of the macula, which serves the central vision.  Wet AMD involves the development of abnormal blood vessels under the retina, which can leak fluid or hemorrhage, causing a sudden loss of vision.  Wet AMD is associated with rapid and severe visual loss, whereas dry AMD is more slowly developing and often not as severe.

The findings of this study are important given that macular degeneration and cataracts are both common in older individuals, and both conditions may contribute to declining vision.  However, cataract extraction essentially cures the visual loss attributable to cataract, where macular degeneration is more difficult to treat.

According to Simon Brunner, MD, professor of ophthalmology at the Rudolph Foundation Hospital of Vienna, Austria, one of the problems with performing cataract surgery on patients with presumed macular degeneration is that fluorescein angiography (FA) is not used routinely, making it difficult to determine with certainty whether the patient has wet AMD or dry AMD, and in cases of wet AMD, if the abnormal vessels are of the "classic" nature, or of the "occult" type.  FA involves the injection of a fluorescent dye into an arm vein followed by photography of the retina.  Abnormal vessels can then be well visualized by their behavior during the photography.

At the 2005 meeting of ARVO (Association for Research in Vision and Ophthalmology), Dr. Brunner presented findings from 30 patients who completed an ongoing study. Researchers are measuring parameters such as visual acuity, contrast sensitivity, cataract staging, visual function, and FA. The main endpoint is progression of AMD over 6 months. The study will eventually enroll 320 patients into an early surgery group or a control group.

Macular drusen (yellow-white deposits in the retina typical in both wet and dry AMD) were observed in all patients and atrophy of the pigmented epithelium was seen in 57 percent to 62 percent, the composition of the AMD did not change over the 6-month post-surgical period.

Functional test results were positive in most patients, with 17 patients in the early-surgery group recording an average increase in distance acuity from 0.26 (20/70 - 20/80) to 0.33 (20/60) on the Snellen chart after 6 months.

There was virtually no difference in distance acuity in the control group (n=13), where the Snellen scores increased from 0.22 (20/80 - 20/100) to 0.27 (20/70 - 20/80) . There was a similar small but important increase in subjective visual function, with the VF-14 questionnaire (a written survey completed by the patient about different visual tasks in their lives) showing an average increase from 2.72 to 2.92 points in the study group and from 2.43 to 3.04 points in the control group. FA did not reveal any growth or shrinkage in size of AMD lesions.

According to Dr. Brunner, these findings compare with two previously published retrospective studies, which in contrast showed that cataract surgery worsened early AMD and one showing that surgery almost doubled the risk of progression of wet AMD.

The results of this small ongoing study seem to suggest that cataract surgery does not lead to wet AMD, and that there may not be any reason to postpone surgery in these patients. Surgery was postponed, however in those patients whose AMD was seen to be leaking on FA, even if this leakage was asymptomatic. Dr. Brunner recommended that FA be mandatory to detect those cases before surgery is considered.

The study will continue in Vienna and four other European centers for another 4 years.





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