• Written By: Chirag P. Shah, MD, MPH

    This analysis of Comparison of Age-Related Macular Degeneration Treatment Trials (CATT) participants found that sustained visual acuity loss was relatively rare and due mainly to foveal scar, pigmentary abnormalities or geographic atrophy.

    A total of 5.9% of eyes of CATT participants developed sustained visual acuity loss of 15 letters or more during two years of treatment with either ranibizumab or bevacizumab. Visual acuity decreased gradually over time, with 83.7 % due to foveal scarring, pigmentary abnormalities, and geographic atrophy. 

    Baseline factors predictive of sustained visual acuity loss included presence of nonfoveal geographic atrophy, larger area of choroidal neovascularization and bevacizumab treatment, with the risk being 3% higher among eyes treated with bevacizumab.

    With only 61 eyes with sustained visual acuity loss, the authors were unable to detect any difference between bevacizumab and ranibizumab in the causes of vision loss. They note that foveal scarring was more frequent among those treated with bevacizumab and foveal geographic atrophy was more common in those treated with ranibizumab, but not to a statistically significant degree.

    The authors suggest that treatments targeting prevention of scar formation or geographic atrophy may help optimize outcomes in the future.