Reproducibility of Macular Thickness Measurements Using Cirrus SD-OCT in Neovascular Age-related Macular Degeneration

Purpose: To assess the test-retest variability of central and sectorial macular thickness measurements obtained by Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) in neovascular age-related macular degeneration (nAMD).

Methods: Macular thickness measurements of nine standard ETDRS subfields were obtained and analyzed. The repeatability of macular thickness measurements by Cirrus HD-OCT was assessed by examining the intrasession within subject standard deviation (Sw), coefficient of repeatability (CR), and coefficient of variation (CV), before and after eyes with retinal segmentation errors were excluded.

Results: Forty-nine nAMD eyes of 49 consecutive patients were included in the study. The CR for the central macular subfield was 42.4 microm (10.5%) and ranged from 12.1 microm (3.7%) for the outer nasal to 41.8 microm (11.4%) for the inner nasal subfields. In a secondary analysis, eyes affected by erroneous detection of inner and outer retinal boundaries (6/49, 12.24%) were excluded. The revised coefficient of repeatability for the central macular subfield was 26.1 microm (8.1%) and ranged from 10.3 microm (3.8%) for the outer superior to 30.2 microm (8.3%) for the inner nasal subfields.

Conclusions: Overall, the test-retest variability of Cirrus HD-OCT is good for the central and sectorial macular subfields, with a low incidence of scan artifacts.