Purpose:
Retinal thickness on optical coherence tomography (OCT) has shown variable correlation with visual acuity in patients with retinal disease. The speed and sensitivity of spectral domain OCT has provided increased consistency in the identification of fine outer retinal structures allowing their quantification. The goal of this study was to explore the correlation between outer retinal substructures and visual acuity in eyes with dry AMD.
Methods:
One hundred eyes of 100 consecutive patients with dry AMD and no other retinal disease, who underwent spectral domain (SD) OCT (Topcon 3D-OCT) were included in this analysis. Raw OCT data was analyzed using OCTOR software, which permits graders to manually draw boundaries. The internal limiting membrane, inner outer nuclear layer (ONL) border, external limiting membrane, photoreceptor inner and outer segments (IS and OS) junction, outer photoreceptor border, inner and outer retinal pigment epithelium (RPE) borders, and Bruchs’ membrane were drawn on all required B-scans, where visible, by certified Doheny Image Reading Center graders. Areas, thicknesses and volumes of RPE, IS, OS, ONL, and the total retina were calculated for the foveal central subfield, which were correlated with the log MAR best corrected visual acuity.
Results:
Thickness, volume and area measurements of the various quantified layers, as well as the correlation coefficient and P-value with visual acuity are shown in Table. Area, thickness and volumes of the total retina, ONL, IS and OS all showed statistically significant associations (P<0.05) with log MAR best corrected visual acuity. The most predictive model was: ONL area and thickness + photoreceptor IS area and thickness.
Conclusions:
The integrity of outer retinal substructures in the foveal central subfield does appear to correlate with visual acuity in these patients. The correlation, however, is only moderate and does not fully explain the variability in acuity in these patients.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration