First Author: C.Schell SPAIN
Co Author(s): B. Rodriguez Aguado B. Delas G. Julio M. Asaad
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To evaluate healthy outer retinal layer thickness, it is to say,external limiting membrane (ELM), photoreceptor inner and outer segment (IS/OS) junctions, and cone outer segment tips (COST) using optical coherence tomography (OCT). The aim of this study is to establish preliminary percentiles of these layers and to measure central domelike appearance of ELM and IS/OS layers
Hospital Consorci de Terrassa, Barcelona, Spain
A case series of 300 eyes from 300 healthy patients (42% men and 58% women) between 7 and 94 years ( mean age 56 ± 19 years) were prospectively analysed. OCT images were taken using a Cirrus HD-OCT 4000 (Carl Zeiss Meditec Inc., Dublin, CA; version 5.0.0). The presence of outer foveal layers were classified as continuous (cat_2), discontinuous (cat_1), and no visible (cat_0) ELM thickness was defined as the distance between this line and the inner border of the retinal pigment epithelium (RPE). IS/OS bulge represented the distance between the hyperreflective IS/OS line and the inner border of the RPE. The mean of three measurements from each feature in each eye was used for the statistical analys
Mean IS/OS thickness was 44 μm (range: 16-65 µm) with a standard deviation (SD) of 5.882μm. 1st percentile was set in 27 µm; 5th percentile=34µm; 95th percentile= 52 µm; and 99th percentile=61 µm. Mean ELM thickness was 58 μm (range: 21-90 µm) with a standard deviation (SD) of 22.067 μm. 1st percentile= 24 µm; 5th percentile=27µm; 95th percentile= 84 µm; and 99th percentile=89µm. There were no significant relationship between both thicknesses and age (p>0.05; Pearson’s correlations) or sex condition (p>0.05; student t test).
This study establishes a preliminary database for foveal thickness of IS/OS and ELM in healthy retinas by OCT. Patient age and sex seem not to influence on these features. Outer layers thickness and its measure could be used as an indicator of early stages in foveal photoreceptors diseases. FINAL DISCLOSURE YES /NO The authors declare no conflict of interest and no sources of funding of this work.