Quantitative comparison of optical coherence tomography after pegaptanib or bevacizumab in neovascular age-related macular degeneration

Abstract

Purpose: To demonstrate the benefit of enhanced quantitative analysis of optical coherence tomography (OCT) images using computer-assisted grading to compare the short-term morphologic effects of pegaptanib and bevacizumab treatment for neovascular age-related macular degeneration (AMD).

Design: Retrospective consecutive case series.

Participants: Fifty-three cases with neovascular AMD undergoing pegaptanib or bevacizumab therapy.

Methods: Fifty-three consecutive cases of patients who underwent StratusOCT imaging followed by treatment with either intravitreal pegaptanib (n = 18) or bevacizumab (n = 35) for neovascular AMD were retrospectively collected. Raw exported StratusOCT images were analyzed using publicly available custom software (OCTOR) designed to define the boundaries of various spaces manually. Changes in thickness and volume of the retina, subretinal fluid (SRF), subretinal tissue, and pigment epithelial detachments (PEDs) before treatment and at 3 months after treatment were calculated and compared between treatment groups. OCTOR software measurements after manual grading were also compared with the automated StratusOCT output.

Main outcome measures: Volume and thickness measurements calculated by the automated StratusOCT software and the manual grading software OCTOR.

Results: Intravitreal bevacizumab resulted in a statistically significant greater reduction of total retinal volume than pegaptanib (-0.88+/-1.4 mm(3) vs. -0.07+/-0.5 mm(3), P = 0.003). Mean foveal central subfield (FCS) retinal volume decreased from 0.26+/-0.1 mm(3) to 0.21+/-0.1 mm(3) (P = 0.001) in the bevacizumab group and remained constant at 0.22+/-0.1 in the pegaptanib group 3 months after injection. Subanalysis of the SRF, subretinal tissue, and PEDs revealed statistically significant reductions of the total volume of all 3 spaces after bevacizumab injections but no significant change after pegaptanib treatment. Automated StratusOCT output measurements of FCS thickness, foveal center point thickness, and total volume of the retina did not reveal a statistically significant difference between the treatments.

Conclusions: Differences in morphologic response between treatments were less apparent on automated StratusOCT output than on computer-assisted analysis. Although intravitreal bevacizumab was associated with a greater short-term reduction in features of exudation than pegaptanib therapy, the retrospective design of the study limits the significance of this finding. Computer-assisted subanalysis of OCT data, however, may be a useful tool in more precisely defining the anatomic effects of therapies for neovascular AMD.