A cross-sectional study to compare the regional corneal thickness profiles in various age groups of Saudi population using 7 mm wide optical coherence tomography scans

Abstract

Measuring age-matched normative corneal thickness (CT) values in the center and peripheral regions can be useful in clinical practice. To determine the influence of age and gender on the central, paracentral and mid-peripheral corneal pachymetry profile in normal eyes using spectral domain optical coherence tomography (SD-OCT); and to estimate the average regional CT profiles across all the age groups. Five ninety-six healthy eyes of 298 subjects aged between 10 and 98 years were evaluated using REVO FC anterior segment SD-OCT with predefined concentric corneal ring-shaped zones. CT was calculated in 17 sectors within a central 7-mm circle. Central zone CT (CCT: 2mm), paracentral (PCT: 2 to 5-mm), and midperipheral (MPCT: 5 to 7-mm) in the superior, superior temporal, temporal, inferior temporal, inferior, inferior nasal, nasal and superior nasal cornea; minimum, maximum, median thickness within the 7-mm diameter area were recorded. The mean CT in corresponding zone was compared between genders and correlations with age were evaluated. The distribution of CCT was 537.9±38µm with no significant difference between right and left eyes, or between males and females CCT. No significant difference noted between male and female participants with respect to age, and no interocular asymmetry in CT was identified either in paracentral or midperipheral zones (17 sectors). The PCT was 1.6% to 5.2% thicker whereas the MPCT sector was 2.3% to 11.4% thicker than the CCT, with the paracentral and midperipheral sectors’ superior and superior nasal zones were the thickest zones in the normal population. The mean paracentral inferior temporal (537.9±38.0) and temporal (538.7±37.2) zones’ CT were similar to mean CCT-2mm (537.7±36.3). CT varied with age in the seven groups of both genders, specifically in the paracentral and mid-peripheral zones. CT decreases, but its dependence on age is weaker. The CT increased gradually from the center to midperipheral ring with the superior and superior nasal regions had the thickest CTs, while the thinnest points are located primarily in the temporal and inferior temporal cornea. With the help of SD-OCT, this is the first study establishes the normative central, paracentral, mid-peripheral, and minimum CT data, which differ significantly from Saudi Arabians in location and magnitude. Based on the results, decisions regarding refractive surgery and corneal diagnosis can be made.