Relationship between peripapillary choroidal thickness and degree of tessellation in young healthy eyes

Purpose To determine the relationship between the peripapillary choroidal thickness (ppCT) and the degree and distribution of the tessellation in the fundus of normal eyes. Methods This was a prospective, observational cross-sectional study of 118 right eyes of young healthy volunteers. The ppCT was measured from the optical coherence tomography (OCT) circle scans manually at eight sectors: the nasal, supranasal superior, supratemporal, temporal, infratemporal, inferior, and infranasal sectors. The subjective degree of the tessellation in the color fundus photographs (CFPs) was classified into three categories: non-tessellated (NT), weakly tessellated (WT), and strongly tessellated (ST) in same sectors. The objective degree of tessellation designated by the tessellation fundus index (TFI) which was calculated as TFI = (R - G)/(R + G + B) using the mean value of the red-green-blue intensities of the CFPs. The differences in the ppCT and TFI for the three tessellation groups were analyzed. The correlations between the TFI and the ppCT were also determined. Results The mean age of the subjects was 25.8 years and the mean axial length of the eye was 25.5 mm. The inter-rater agreement of the subjective classifications was high with a Fleiss kappa of 0.71. The ppCT was significantly thinner in eyes with higher degrees of tessellation (P < 0.05) in all sectors. The TFIs were significantly and negatively correlated with the ppCTs in all sectors (r = - 0.44 to - 0.24, P < 0.05) except the nasal and the supranasal sectors. Conclusion The degree of peripapillary tessellation is significantly correlated with the ppCT in young healthy eyes, and it has large individual and geographic variations.