Early Detection of Choroidal Neovascularization in AMD Could Improve Visual Outcomes

The typical nAMD patient loses lines of vision before being diagnosed.

Using anti-vascular endothelial growth factor (VEGF) agents to treat patients with neovascular age-related macular degeneration (nAMD) can stabilize or improve vision and help ensure continued maximal functioning.

Upwards of 95% of patients treated with these agents maintain visual acuity (VA) within 3 lines of their baseline value at nAMD diagnosis, and 30-40% can expect VA to improve 3 lines during the initial 2 years of treatment.

However, the magnitude of change in vision, a key outcome measure in clinical studies of treatment effectiveness, is less important to patients than having an absolute VA that allows for reading and driving after treatment. And numerous studies have shown that the better the VA when anti-VEGF therapy is started, the greater the chances of better VA in the next 2 years. Thus, detecting nAMD as early as possible when vision is fairly good is crucial.

Allen Ho, MD, (pictured) of Mid Atlantic Retina at Wills Eye Hospital, Philadelphia, PA, made these key points in a recently published special communication. Ho noted that the data raise questions about current management strategies for intermediate AMD, particularly for patients with clinical characteristics that confer a high risk of progression to nAMD.

Several studies indicate that as intermediate AMD progresses to nAMD, patients typically lose a mean of at least 3—5 lines of vision, Ho wrote. The typical patient has nAMD for 6–12 months before being diagnosed and treated.

Ho added that because many patients have considerable visual impairment at nAMD diagnosis, anti-VEGF treatment might not offer them good long-term visual outcomes. As a result, Ho advocated identifying patients with nAMD before considerable loss of vision occurs to reduce vision loss during anti-VEGF therapy and to improve VA outcomes.

Ho noted that younger age and smaller area of choroidal neovascularization (CNV) were two key baseline features associated with better VA outcomes after anti-VEGF treatment in post hoc analyses of the HARBOR and MARINA trials of ranibizumab for nAMD. These features are also characteristics of early stage CNV.

In addition, Ho cited evidence that smaller CNV lesions grow more quickly than larger ones. A systematic review of recent studies found the rate of growth in small lesions to be approximately 26 μm/day compared to 6 μm/day for large lesions.

As a result, the growth of small lesions produces greater incremental loss of vision than does the growth of larger lesions. These findings also favor intensive evaluation of intermediate AMD patients to detect and treat CNV and nAMD early in its course and thereby limit the growth of CNV lesions and related vision loss.

“The data suggest there is greater need to detect CNV when VA is relatively good,” Ho concluded, adding that this policy could “significantly improve VA outcomes by addressing nvAMD before it has caused too much irreversible macular damage and vision loss.”

The special communication, “The potential importance of detection of neovascular age-related macular degeneration when visual acuity is relatively good,” appears in the March, 2017, issue of JAMA Ophthalmology.

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