Consider the risk:benefit ratio with ARM, cataract surgery

Issue: May 2006

ByJoseph Hallak, OD, PhD, FAAO

Neovascular age-related maculopathy (ARM) has been observed shortly after cataract surgery in some patients. Clinicians have questioned whether cataract surgery increases the risk for developing ARM or if patients with cataracts are more prone to ARM. Anecdotal evidence, clinical case series, case controlled studies and cross-sectional studies have yielded inconsistent results.

Joseph Hallak, OD, PhD, FAAO [photo]
Joseph Hallak

No change in status after surgery

Dr. Boscarino and colleagues (including the author and M. Morcos) looked at 120 patients in a Veterans Administration Medical Center setting. All patients were male, with an average age of 79 years (range: 68 to 89 years). Average follow-up time was 10.8 months, with a range of 1.5 to 27 months. Twenty-three patients had documented maculopathies, and 18 of 23 were dry before and after cataract surgery. Three of 23 had no diagnostic view of the fundi prior to surgery; however, after surgery, two had the dry form of ARM and one had geographic atrophy.

One patient had pigment epithelium detachment (PED) before surgery with no change after surgery, and one patient had no ARM before surgery and dry ARM after surgery. Three of the 23 had fluorescein angiography performed prior to cataract surgery: one for cystoid macular edema, one for PED and one for fellow-eye choroidal neovascularization (CNV), but none for suspected CNV in the operated eye.

Overall, 21 of the 23 patients had no change in ARM status after surgery. One patient with no documented ARM prior to surgery was diagnosed with dry ARM after surgery. There was no evidence of progression to either geographic atrophy or CNV, except for one case that could not be documented.

ARM link to cataract surgery found

On the other hand, in 1996, Pollack and colleagues followed 47 patients with bilateral, symmetric, early ARM. One year after extracapsular cataract extraction in one eye only, nine surgical and two fellow eyes developed neovascular ARM. They concluded that operated eyes were 4.6 times more likely to develop ARM than nonoperated eyes.

In 1994, van der Schaft and colleagues found that pseudophakic eyes were 2.7 times more likely to develop neovascular ARM than phakic eyes (Wang 2003).

Large-scale study results

Large, statistically significant and well-controlled studies can provide important information about ocular conditions. In the Beaver Dam Eye Study, 4,926 patients were enrolled between March 1, 1988, and Sept. 14, 1990. Five years later, 81.1% of the survivors were entered in a follow-up examination, and 10 years later, 82.9% of those participated in another follow-up. “The 10-year incidence data … show an increased risk for early ARM in eyes with cataract at baseline, particularly nuclear cataract, and for progression of ARM and incidence of late ARM in eyes that underwent cataract surgery,” said the researchers.

The Blue Mountain Eye Study examined 3,654 residents aged 49 and older from 1992 to 1994 and 75.1% of the survivors 5 years later.

Study protocols

The two studies were similar in their protocols for patient selection, data collection and analysis. Retinal photographic documentation and grading also followed the same pattern. They are both large cohort and well-controlled studies. All participants had comprehensive eye examinations with pupil dilation and crystalline lens and stereoscopic retinal photography of the macula and surrounding 30·. All late-stage ARM cases at baseline or later were confirmed by the study principal investigators. Both studies controlled for various factors associated with ARM.

ARM was defined following the International ARM Classification. Late-stage lesions included geographic atrophies equal to or greater than 175 µm in diameter at the macula. Definition of ARM included four categories:

fewer than five small drusen (less than 63 µm in diameter) and visual acuity of 20/32 or better
fewer than 20 small drusen with diameters between 63 and 124 µm and visual acuity of 20/32 or better
no advanced ARM in either eye; visual acuity at least in one eye of 20/32 or better; the presence of one large drusen (diameter more than 125 µm); extensive intermediate drusen or geographic atrophy not involving the macula
advanced ARM in one eye

Combined analysis

The 5-year follow-up results were pooled, and populations from both studies (more than 6,000 patients) were combined and analyzed statistically. The conclusion was “that cataract surgery may be associated with an increased risk for developing late-stage ARM, particularly neovascular ARM. The mechanism for this association is not clear.”

AREDS results analyzed

In a study presented at the 2005 American Academy of Ophthalmology meeting, Ferris and colleagues criticized these studies as not having “reliable information regarding the preoperative status of the retina.”

They turned to the Age-Related Eye Disease Study (AREDS), where progression to advanced ARM is measured by a photographic reading center or the verification of photocoagulation at a study visit. The AREDS population is smaller than the combined or the individual studies above (Beaver Dam and Blue Mountain).

According to Ferris, of the 19% who had cataract surgery, 5% progressed to advanced ARM only after a mean follow-up of 6 years. They concluded that “cataract surgery did not significantly accelerate or was not associated with progression to NV AMD [neovascular advanced macular disease].” No indication was given to indicate which group of patients was considered: the control or the one taking the antioxidant supplements considered in the AREDS.

Consider risk:benefit ratio

In any event, because cataract extraction results in significant improvement of quality of life and visual function, many surgeons feel justified in operating on cataractous eyes with ARM. The primary concern is the progression toward the debilitating form of ARM.

So, what do we tell our patients? First, if cataract surgery is necessary, retinal consultation and fluorescein angiography is advisable. Second, in the presence of a 20/200 cataract and minimal drusen (category 1 or 2), the benefits from cataract surgery outweigh the risks.

However, the question still remains whether the outcome of ARM progression would be the same regardless of the skill of the surgeon and complications of the surgery. A small study is being conducted at Nassau University Medical Center under the author’s direction to look into the progression of ARM, taking into consideration the length and type of surgery as well as the degree of trauma inflicted during the procedure.

For more information:
Joseph Hallak, OD, PhD, FAAO, is in private practice in Hicksville, N.Y. He can be reached at 183 Broadway, #308, Hicksville, NY 11801; (516) 935-0717; e-mail: drjhallak@aol.com.

References

Pollack A, Marcovic A, Bukelman A, Oliver M. Age-related macular degeneration after extracapsular cataract extraction with intraocular lens implantation. Ophthalmology. 1996;103:1546-1554.

Klein R, Klein BEK, Tien YW, Tomany SC, Cruickshanks KJ. The association of cataract and cataract surgery with the long-term incidence of age-related maculopathy — The Beaver Dam Eye Study. Arch Ophthalmol. 2002;120:1551-1558.

Wang JJ, Klein R, Smith W, et al. Cataract surgery and the 5-year incidence of late-stage age-related maculopathy — Pooled findings from the Beaver Dam and Blue Mountain Eye Studies. Ophthalmology. 2003;110(10): 1960-1967.

Ferris FL III, Chew EY, Gensler G, Milton R, AREDS Research Group. Controversy of cataract extraction and AMD progression. Presented at the AAO meeting, 2005 Subspecialty Day/Retina, Chicago.