Because there is limited data on the risk of progression from non-exudative macular neovascularization (MNV) to the exudative form in patients with age-related macular degeneration (AMD), researchers recently conducted a meta-analysis. Results were recently published in American Journal of Ophthalmology.

AMD patient with a large, elongated PED and no sign of fluid on the OCT has an extensive MNV network present on the avascular complex of his OCT-A scan. Photo: Jessica Haynes, OD, and Mohammad Rafieetary, OD. Click image to enlarge.

Authors identified 16 eligible studies with a total of 384 eyes showing non-exudative MNV and determined the prevalence of exudative progression at one and two years. Exudative progression had occurred in 20.9% of eyes at one year and in 30.7% at two years. Similar results were observed in the individual participant meta-analysis, showing exudative progression in 18.9% of eyes at one year and 31.3% at two years. Risk factors for a fast progression were the presence of subretinal lipid globules, large MNV areas, rapid MNV growth, growth in pigment epithelium detachment height and width, appearance of a branching pattern and development of a hyporeflective halo around the MNV, the authors noted.

In previous studies, new neovascular AMD occurred in 15.9% to 26.4% of patients at one year and 23.8% to 38.8% at two years, while another showed that 16.6% to 20.6% developed the condition at two years.

“Although these progression rates may seem similar to those identified in our meta-analyses, OCT-A studies that distinguish between eyes with and without non-exudative MNV highlight a clear clinically and statistically significant difference,” the authors wrote in their article for AJO.

In eyes with non-exudative MNVs, some studies showed that the common themes for risk factors for a faster exudative progression included larger MNV areas and fast MNV growth.

“Although some risk factors identified across studies (i.e., growth in PED height, growth in PED width, subretinal lipid globules) can be recognized using macular OCT, recognition of MNV size and growth may require repetition of OCT-A at follow-up. Therefore, another clinically practical important point from our review is that follow-up visits of eyes with known presence of non-exudative MNV should include repetition of OCT-A,” the authors emphasized.