Central corneal thickness and degree of myopia in the adult myopic population of Almeria, Spain

The aim of this work is to determine the values and study the relationship of central corneal thickness (CCT) and the degree of myopia (DM) in the adult myopic population aged 20-40 years in Almeria, Southeast Spain. To our knowledge this first study addressing these issues in this region. A cross-sectional, descriptive, observational study in which 310 myopic patients aged 2040 years were selected by sex- and age-stratified sampling which was proportionally fixed to the population strata size, for which 20% prevalence of myopia, 5% epsilon and 95% confidence interval were hypothesised. CCT and DM and their relationships were studied by calculating means, the standard deviation, the 95% confidence interval for means, the median, Fisher's (asymmetry) coefficient, range, maximum and minimum and BrownForsythe's robust test for each variable. CCT measurements were taken with a DGH 4000 B ultrasound pachymeter, and subjective and objective ocular refractions were performed with a Nidek AR-6000 auto-refractor. In the adult myopic population of Almeria aged 20-40 years (mean age, 29.8), the mean overall CCT was 550.12 micrometers. In general, no statistical differences were found between the right (548.98) and left (551.19) eyes (p=0.426). The CCT was thicker for men (553.62) than for women (546.61) (p=0.014), and there were no significant differences (p=0.553) in CCT for the 20-40 age group; therefore CCT is stable with age. The overall DM was -4.18 dioptres, with no statistically significant differences between the right (4.17) and left (4.19) eyes (p=0.901) in general. Men had less myopia (media -3.82) than women (mean -4.54) (p<0.001). Myopia was stable in the 20-40 age group (p=0.089). We found no linear relationship between CCT and DM.