Normative Database and Color-code Agreement of Peripapillary Retinal Nerve Fiber Layer and Macular Ganglion...

Evaluate the distribution and the color probability codes of the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in a healthy Vietnamese population and compare them with the original color-codes provided by the Cirrus spectral domain-optical coherence tomography.

This is a cross-sectional study. We recruited nonglaucomatous Vietnamese subjects and constructed a normative database for peripapillary RNFL and macular GCIPL thickness. The probability color-codes for each decade of age were calculated. We evaluated the agreement with κ coefficient between optical coherence tomography color probability codes with Cirrus built-in original normative database and the Vietnamese normative database.

In total, 149 eyes of 149 subjects were included. The mean age of enrollees was 60.77 (±11.09) years, with a mean spherical equivalent of +0.65 (±1.58) D and mean axial length of 23.4 (±0.87) mm. Average RNFL thickness was 97.86 (±9.19) µm and average macular GCIPL was 82.49 (±6.09) µm. Agreement between original and adjusted normative database for RNFL was fair for average and inferior quadrant (κ=0.25 and 0.2, respectively); and good for other quadrants (range, κ=0.63 to 0.73). For macular GCIPL κ agreement ranged between 0.39 and 0.69. After adjusting with the normative Vietnamese database, the percent of yellow and red color-codes increased significantly for peripapillary RNFL thickness.

Vietnamese population has a thicker RNFL in comparison with Cirrus normative database. This leads to a poor color-code agreement in average and inferior quadrant between the original and adjusted database. These findings should encourage to create a peripapillary RNFL normative database for each ethnicity.