A novel automated method for the objective quantification of Retinal layers reveals sequential changes that occur in the Normal retina with age

Abstract

This paper develops a novel automated image processing algorithm of standard retinal ocular coherence tomography (SD-OCT), that allows for an objective investigation of age-related retinal changes in normal subjects, based on automated quantitative reflectivity changes. A database of SD-OCT retinal scans (Zeiss Cirrus HD-OCT 5000) was prospectively established from 200 normal subjects without clinical evidence of retinal pathology. A novel segmentation algorithm was applied to extract retinal layers and normalize the reflectivity range, utilizing a novel normalized reflectivity scale (NRS) ranging from 0 units (vitreous) to 1000 units (retinal pigment epithelium [RPE]). NRS decreased with age overall, with the greatest declines seen in the ellipsoid zone (3.91 ± 2.11 NRS · yr −1 ,F 1,322 = 100.9;p < 0.0001), and NFL (3.84 ± 1.72 NRS · yr −1 ,F 1,322 = 112.6;p < 0.0001). Normal aging had little to no effect on the reflectivity of RPE or ELM. It was possible to report the reflectivity changes in the retina that occur in normal aging subjects. This novel algorithm shows promise of early detection of occult retinal pathology otherwise undetectable.