Normative database for separate inner retinal layers thickness using spectral domain optical coherence tomography in Caucasian population

PURPOSE Develop the first normative database of the thickness of every inner retinal layer in the macular area in a healthy, Caucasian population between 18 to 87 years old, using Spectralis Optical Coherence Tomography (OCT). METHODS On this transversal, observational study, 300 patients between 18 to 87 years old and without an ophthalmological condition were recruited. Macular OCT scans were performed on all patients (Spectralis OCT, Heidelberg Engineering). An axial length measurement, and keratometry were performed using an optical biometer. The volume and thickness of the different macular sectors of the inner retinal layers (retinal nerve fiber layer (RNFL), ganglion cells layer (CGL) and inner plexiform layer (IPL)) were analyzed with the Spectralis OCT segmentation software. An eye was randomly selected for each patient. RESULTS 297 patients (179 females and 118 males) were included in the study. The mean age was 56.07 years (range: 40.50-72). The multivariate analysis showed a positive correlation between the RNFL thickness and the axial length (p < 0.001). The mean central retinal thickness was 278.2 μm (range: 266-291), the mean central RNFL thickness was 12.61 μm (range: 11-14), the mean central CGL thickness was 17.63 μm (range: 14-21) and the mean central IPL thickness was 22.02 μm (range: 20-25). The multivariate analysis showed a negative correlation between age and CGL thickness and inner IPL thickness (p< 0.001). CONCLUSION This study provides a normative database of the volume of each of the inner retinal layers on a Caucasian population.