Neovascularization, or new blood vessel growth, is a restorative function of the body that assists in healing. When it occurs in the retina, however, it can lead to vision loss. In age-related macular degeneration (AMD) the photoreceptor cells weaken over time. In about 10 to 15 percent of AMD patients, the inflammatory system sends new blood vessels into the photoreceptor layer to carry nutrition to those cells. This process of inflammation is beneficial elsewhere in the body, but in the retina, if left untreated, it can cause permanent central vision loss.
Clearly, neovascularization in the retina has a negative effect that must be blocked. New research, however, suggests that it may actually be a double-edged sword. An AREDS2 Research Study Group has found in a follow-up study of 757 eyes with geographic atrophy (advanced dry AMD) that enlargement of the areas of cell degeneration seems to slow in some patients prior to leakage of the blood vessels (exudation). This means that the tissue could likely be benefitting from the improved blood circulation, while the vision of the patient is being simultaneously threatened by impending exudation.
The dichotomy presents some interesting therapeutic challenges that warrant further evaluation in prospective studies.
SOURCE: Progression of Geographic Atrophy with Subsequent Exudative Neovascular Disease in Age-Related Macular Degeneration AREDS2 Report 24. Christopher K. Hwang, MD, PhD, et al (Published October 15, 2020 DOI: https://doi.org/10.1016/j.oret.2020.10.008