Optical coherence tomography evidence on the correlation of choroidal thickness and age with vascularized retinal layers in normal eyes

Purpose: To correlate choroidal thickness (CT) and age with vascularized retinal layer and outer retinal layer thickness in normal eyes. Methods: This was a prospective, cross-sectional study. Complete ophthalmological examination, biometry, and enhanced depth imaging spectral domain optical coherence tomography were performed. Choroidal and individual retinal layer thickness measurements were obtained. Thickness maps for all layers were evaluated using the 1 mm, 3 mm, and 6 mm early treatment diabetic retinopathy study (ETDRS) macular grid areas. Results: One hundred and twenty eyes were included. Choroidal thickness correlated negatively with age in all ETDRS areas. The ganglion cell layer (GCL) in the 1 mm; the GCL and inner plexiform layer (IPL) in the 3 mm and 6 mm; and the GCL, IPL, and inner nuclear layer in the 6 mm areas correlated negatively with age and positively with CT. Retinal nerve fiber layer thickness in the 6 mm area correlated negatively with age. The retinal pigment epithelium-photoreceptor layer in all areas correlated negatively with age and positively with CT. Conclusion: In normal subjects, vascularized retinal layer thicknesses and outer retinal layer thickness correlate positively with CT and negatively with age. The role of neuronal versus vascular components should be considered when evaluating individual retinal layer thicknesses.