Comparable choroidal thickness between treated eyes and untreated fellow-eyes in patients with unilateral neovascular AMD: a paired-eyes comparative study.

AIMS

To investigate the potential effect of anti-VEGF treatment on choroidal thickness (CT) in unilateral neovascular age-related macular degeneration (AMD) patients.

METHOD

This is a cross-sectional study where patients were included as part of an ongoing prospective study which included patients with unilateral neovascular (n) AMD. The fellow-eye served as control. All patients had spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) done at every visit. CT was measured independently by two graders at five locations: subfoveal, 1500 micron temporal and nasal, 3000 micron temporal and nasal. The average of the measurements was used after statistical verification of their accuracy. CT differences were initially analysed via a paired T-test and later via multiple linear regression. Variables such as number of injections were studied and presence of geographic atrophy (GA) in fellow-eyes was evaluated via SD-OCT.

RESULTS

A total of 112 patients met the inclusion criteria (Female 67%). The median (IQR) years of treatment was 2.6 (4.1). The subfoveal choroidal thickness (SFCT) in the neovascular (NV) eye appeared thinner in the NNV eye initially (-11.0 μm difference between NV and NNV SFCT (CI -23.4 to 1.3). However, after age-adjustment this trend disappeared (CI -29.8 to 4.6). In fact, apart from age (CI -6.2 to -0.1)), no other variable including number of anti-VEGF injections (CI -1.5 to 1.4) predicted SFCT. Presence of GA in fellow eyes did not influence the SFCT compared to non-GA fellow eyes, difference (CI -59.7 to 46.6).

CONCLUSIONS

This study shows no statistically significant CT difference in NV versus NNV eyes. There was no relationship between number of injections and CT.

KEY MESSAGES

What is known Intravitreal injection with anti-vascular endothelial growth factors (anti-VEGF) is the mainstay treatment for exudation secondary to neovascular AMD. One quarter of anti-VEGF treated neovascular AMD patients will develop signs of macular atrophy within 2 years, possibly related to anti-VEGF treatment. What this study adds A hypothesized mechanism for atrophy induction is the effect of anti-VEGF on choroidal thickness. In this cross-sectional study, we found a non-significant 11 micron difference between anti-VEGF treated eyes and non-treated eyes in long-term follow-up neovascular AMD patients. A relationship between choroidal thinning and the number of anti-VEGF injections was furthermore not shown. How this study might affect research, practice or policy There is no significant choroidal thickness difference between anti-VEGF treated and non-treated long-term follow-up neovascular AMD. We therefore suggest that atrophy induction through choroidal thinning secondary to anti-VEGF injections is of limited concern.