Purpose:
To evaluate choroidal area and subfoveal choroidal thickness in patients with exudative age-related macular degeneration (AMD) and to investigate the effect of disease duration and anti-vascular endothelial growth factor (anti-VEGF) therapy on choroidal thinning.
Methods:
A total of 36 eyes of 36 patients undergoing anti-VEGF monotherapy for exudative AMD were enrolled in this prospective case series study. Anti-VEGF injections were administered to patients on an as-needed basis guided by comprehensive ophthalmic examination and spectral-domain optical coherence tomography (SD-OCT) findings. Patients were scanned by enhanced-depth imaging (EDI) using a clinical scanner by adjusting camera position to generate an inverted image. Choroidal area and subfoveal choroidal thickness were calculated from a foveal EDI B-scan using a custom-written automated computer algorithm. Clinical parameters were analyzed to extract Snellen visual acuity, duration of disease, anti-VEGF injection history, and patient demographics.
Results:
The median age of the cohort was 81.7 (IQR 75.5 - 85.7) years. Patients underwent a median of 4 (IQR 2 - 12) anti-VEGF injections over a median of 24.8 (IQR 4.0 - 39.6 months). Mean choroidal area ± STD measured by EDI OCT was .979 ± .399 mm2 while subfoveal choroidal thickness was 203 ± 96 microns. There was a strong correlation between choroidal area and thickness in the same eye (R2 = .95, p<.001). On the other hand, there was no relationship of choroidal parameters to subfoveal retinal thickness. Choroidal area showed a statistically significant negative correlation to duration of exudative disease (p=.0019) and to number of anti-VEGF injections (p=.0034). Subfoveal choroidal thickness was also negatively correlated to duration of exudative disease (p=.011) and number of injections (p=.0052).
Conclusions:
Longer duration of exudative AMD and greater number of anti-VEGF injections were associated with decreased choroidal thickness and area in univariate analysis. These differences may reflect structural or vascular alterations of the choroid in response to disease progression and anti-VEGF therapy.
Keywords: age-related macular degeneration • choroid • imaging/image analysis: clinical