Subfoveal choroidal thickness as a prognostic factor in exudative age-related macular degeneration.

Aims: To investigate the relationship between subfoveal choroidal thickness (SFCT), visual acuity (VA), optical coherence tomography (OCT) features and total anti-vascular endothelial growth factor (VEGF) treatments to determine whether SFCT serves as a prognostic factor in age-related macular degeneration (AMD).

Methods: This is a retrospective case series of 62 consecutive treatment-naive patients with exudative AMD followed for 1 year and treated with treat-and-extend or anti-VEGF protocols. SFCT was measured at three locations using Cirrus HD-OCT (the foveal centre and 500 um nasal and temporal to the fovea) at presentation, 3, 6 and 12 months. Demographic characteristics, OCT imaging biomarkers and VA were recorded.

Results: Mean SFCT at baseline was 187 µm (range: 70-361 µm). There was a trend of decreasing SFCT at 1 year (173 µm) compared with 3 months (175 µm) and baseline (188 µm) (p=0.2). There was no correlation between baseline SFCT and presence of subretinal fluid (p=0.2), intraretinal fluid (p=0.6) or subretinal hyper-reflective material (p=0.4) at baseline. The mean number of injections at 1 year was 6.6 (range: 2-12). Increased SFCT at baseline showed statistically significant correlation with a higher number of intravitreal injections at 1 year (p=0.004). Eyes with SFCT>1 SD above the mean required 50% more injections compared with others. There was no association between SFCT on presentation with baseline and 1 year VA (p=0.7 and p=0.2).

Conclusions: SFCT in naïve patients with exudative AMD may be an important prognostic tool in determining treatment burden. Patients with thicker subfoveal choroid may require increased intravitreal injections.