Abstract
Purpose:
To assess the relation between the relative reflectivity of the inner segment ellipsoid (ISe) band on Spectral domain (SD)-OCT and the cone density measured using adaptive optics.
Methods:
Twenty eyes of 10 subjects were studied. Two subjects were healthy and the others were randomly chosen from a pool of patients presenting retinal diseases impairing bilaterally the ISe layer. Horizontal B-scans were acquired using SD-OCT (Spectralis, Heidelberg, Germany). The relative reflectivity, defined as the ratio between the reflectivity of the ISe layer and the reflectivity of the full retinal thickness was measured, together with ISe thickness, using ImageJ (labo, pays). Cone counts were performed at 2° eccentricity from the fovea (nasal, temporal, superior and inferior areas) using an Adaptive Optics retinal camera (RTX1, Imagine Eyes, Orsay, France) and its dedicated software (AOdetect v0.1™ ,Imagine Eyes, Orsay, France). Correlation coefficients (Pearson r) between the cone density and the others parameters were calculated for each area.
Results:
Cone densities were significantly correlated with the ISe relative reflectivity (r = 0,70 [0,59 ; 0,79] p<0,01), and to a lesser extent with the ISe thickness (r = 0,32 [0,04 ; 0,56] p<0,01) and with BCVA (logMAR) (r = -0,38 [-0,55;-0,21] p<0,01).
Conclusions:
The reflectivity on SD-OCT of the outer retina brings valuable information on photoreceptor density in absence of adaptive optics camera. Further developments in OCT software enabling it uses in a clinical setting would be a useful advance.
Keywords: 550 imaging/image analysis: clinical •
688 retina •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)