Computer-assisted quantification of plus disease after treatment of retinopathy of prematurity with intravitreal bevacizumab

Abstract

Treatment for Type 1 retinopathy of prematurity (ROP) includes laser and, more recently, intravitreal injection of bevacizumab. This study uses ROPtool, a photoanalyzer, to objectively measure changes in retinal vascular dilation and tortuosity (plus disease) following intravitreal bevacizumab. Fundus images from 6 newborns treated with intravitreal bevacizumab for ROP were analyzed using ROPtool to assess for changes in tortuosity, dilation and a calculation of overall plus disease. Measurements were obtained at baseline (n = 6), 1 week (n = 6), and 2 weeks (n = 1) after treatment. Average vessel tortuosity decreased by 49%, dilation decreased by 9% and overall plus disease decreased by 17% in the first week after treatment with bevacizumab. One week later, the average vessel tortuosity decreased by another 20%, dilation decreased by 1%, and overall plus disease decreased by 14%. Few studies have shown objective changes in ROP after treatment with laser but no previous studies have shown similar objective findings after treatment with bevacizumab. This study demonstrates a larger decrease in tortuosity at 1 week post-bevacizumab compared to a previous study of post-laser patients analyzed by Computer Assisted Image Analysis Software (that study found only a 2% decrease in tortuosity and 20% decrease in dilation at 1 week). Objective measurements of plus disease show greater changes in tortuosity 1 week after treatment with bevacizumab compared to a previous study of post-laser changes. Understanding the expected pattern of change over time in retinal vascular dilation and tortuosity following bevacizumab guides clinicans’ expectations for ROP regression following this new treatment.