Nonexudative neovascularization in the fellow eyes of patients with unilateral exudative age-related macular degeneration (AMD) may portend the development of exudative changes, according to a prospective observational study 

This new finding is important as we can now non-invasively identify the high-risk patients who require more regular monitoring," Dr. Chui Ming Gemmy Cheung of the University of Singapore told Reuters Health by email.

In a paper online June 7 in JAMA Ophthalmology, Dr. Cheung and colleagues note that the advent of optical coherence tomography angiography (OCT-A) has made the detection of choroidal neovascularization much easier. However, the clinical significance of such lesions is unclear.

To gain further information, the researchers examined data on 95 Asian patients with exudative AMD. All had had gradable OCT-A, and indocyanine green angiography (ICGA) scans of the fellow eye at baseline and follow-up at least six months apart.

Nonexudative neovascularization was found in 18 (19%) fellow eyes at baseline. Four of these eyes subsequently developed exudation and two further eyes developed exudative changes.

The researchers estimated the annual incidence of development of exudation as being 18.1% in those with nonexudative neovascularization and 2.0% in those who developed exudative neovascularization de novo.

"Thus," they say, "eyes with nonexudative neovascularization are at almost ten times higher risk of developing exudative changes than eyes without these lesions."

Nonexudativee neovascularization

The researchers point out that this outcome is in line with previous findings in a Caucasian population but concede that their study had limitations including the length of follow-up.

"With further follow-up, there could be no difference in the incidence of exudative changes between fellow eyes with or without nonexudative neovascularization," they say.

Dr. Cheung concluded that "this period in which a lesion can remain sub-clinical may offer new opportunities in future to intervene and modify the course of progression." However, the researchers also observed that "there is currently no clinical data to support treatment for nonexudative neovascularization before exudation occurs."

Commenting on the findings by email, Dr. Marco A. Zarbin of Rutgers-New Jersey Medical School, in Newark, told Reuters Health, "the fact that choroidal new vessels can be present and 'dormant' for relatively long periods of times adds to a growing body of evidence that choroidal new vessels may grow in response to local deficits in choroidal blood flow."

Dr. Zarbin, professor and chair of the Institute of Ophthalmology and Visual Science, added that the findings suggest that "patients with clinically active choroidal new vessels in one eye and nonexudative choroidal new vessels in their fellow eye probably merit careful follow-up to detect clinical activation of these nonexudative new vessels so that treatment with anti-VEGF agents can be initiated promptly."

"OCT-A is a relatively new imaging modality among retina specialists,” he added, "but there is increasing evidence that it is going to play an important role in patient management (as well as in the clinical trial design). The present study adds to that body of evidence."