Abstract
Purpose: :
To evaluate change in subfoveal choroidal thickness over time in patients with non-neovascular age related macular degeneration (NNVAMD) as measured by spectral domain optical coherence tomography (SD-OCT).
Methods: :
OCT data was retrospectively collected from 76 eyes of 49 patients with a diagnosis of NNVAMD who underwent high definition raster scanning with frame averaging (4x) using the Cirrus HD OCT (Carl Zeiss Meditec, Dublin, CA). All eyes had at least 12 months of follow-up OCT data available, with 13 eyes having 24 months. Using the digital caliper tool in the Cirrus review software, choroidal thickness at the foveal center was measured from the external side of the retinal pigment epithelial (RPE) band to the choroid-sclera junction. All eyes were measured by two independent, masked observers, and discrepancies were resolved by open adjudication. For cases in which the full-extent of the choroid was visible, choroidal thickness measurements at baseline were compared to measurements at follow-up visits every 6 months up to two years. The presence of RPE atrophy was also evaluated. Choroidal thickness measurements were also correlated with age and best-corrected visual acuity (BCVA).
Results: :
Mean (±SD, range) age of the patients was 78 years (±8.5, 62-98), and 57% (n=28) were women. BCVA at baseline was 0.65 (Snellen~20/80) logMAR (±0.81). The full extent of the choroid was visible in 60% (46/76) of eyes. Mean choroidal thicknesses were 169.7µ (±69, 66-472), 163.8(±67.6, 59-446), 169 (±47.9, 65-274) and 146.4 (±43.9, 52-224) at baseline, 1 year, 18 months and 2 years respectively. Mean change in choroidal thickness was -6.7 (±12.2, p=0.002), -6.3(±9.5, p=0.001) and -10.9 (±12.76, p=0.009) microns at baseline, 1 year, 18 months and 2 years respectively. ANOVA showed a significant reduction in choroidal thickness from baseline to 2 years follow up (p=0.04). No significant correlation was observed between baseline choroidal thickness and age (r=-0.18, p=0.24) or visual acuity (r=-0.05, p=0.74). There was also no correlation (r=-0.49, p=0.08) between the change in choroidal thickness from baseline to 24 months and change in visual acuity.
Conclusions: :
Choroidal thickness measurements in patients with dry AMD appeared to show a modest decrease over time, but this decrease was not associated with a reduction in acuity.
Keywords: choroid • age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)