Abstract
Purpose: :
To assess the relationship between visual acuity (VA) and outer retinal morphology evaluated from spectral domain optical coherence tomography (SDOCT) images in various retinal diseases.
Methods: :
A series of 73 patients (136 eyes) requiring SDOCT for standard of care assessment of retinal disease were recruited for this study. All subjects were scanned using the Topcon 3D OCT-1000 with the cube scan protocol (6 x 6 mm area; 128 B-scans;512 A scans / B scan) The evaluation was limited to the 20 B scans passing through the central subfield (CSF). It included integrity of the external limiting membrane (ELM) and photoreceptor inner segment-outer segment (IS-OS) junction. Every scan was evaluated by two examiners. Using a 3 step scale the ELM and the IS-OS junction in the CSF were graded as absent, abnormal and normal. VA was measured on a Snellen chart with the patient’s habitual refraction and converted to logarithm of minimal angle of resolution (logMAR) units for statistical analysis.
Results: :
All scans obtained were of gradable quality for outer retinal integrity. The percentage agreement and kappa statistics was 69 % (0.53) for grading of the ELM, and 72 % (0.54) for IS-OS. The mean logMAR VA was 0.8 (n=39) for eyes with absent ELM, 0.3 (n=33) for abnormal ELM and 0.2 (n=61) for normal ELM (p value<0.001). For IS-OS status, the mean logMAR VA was 0.9 (n=30) for absent IS-OS, 0.4 (n=38) for abnormal IS-OS and 0.2 (n=65) for normal IS-OS (p value <0.001). The trend in distribution of VA along the 3 step scale of ELM and IS-OS remained in most disease categories although the numbers were small.
Conclusions: :
A statistically significant association between ELM, IS-OS integrity and VA suggests that outer retinal morphology evaluation by SDOCT may provide useful variables for clinical research and care.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual acuity • retina