Abstract
Purpose :
Corneal power varies among patients and is an important consideration in keratorefractive surgery. The purpose of this study is to evaluate corneal power and possible associations in a population representative of United States Adults
Methods :
Population-based, cross-sectional study of adults age 18 and older from the 2005-2008 National Health and Nutrition Examination Survey (NHANES). Statistical analysis was performed with R Version 3.5.1. Serial logistic regression was carried out to identify associations between specific factors and keratometry (K) values. Main outcome measures were right eye steepest dioptric corneal power.
Results :
A total of 6756 subjects met inclusion criteria, comprised of 3464 (51.3%) male and 3292 (48.7%) female subjects.
The paired T-test revealed no significant differences between right eye and left eye K values, suggesting that findings related to right eye K values can be generalized to left eyes. Thus, right eyes were selected for analysis.
The paired T-test revealed no significant differences among the steepest K value, flattest K value, and magnitude of corneal astigmatism among right eyes and among left eyes, suggesting that findings related to the steepest K value can be generalized to other K values. Steepest K value was selected for analysis.
Average right eye steepest K value was 44.12 Diopters (D), with a standard deviation of 1.70D. Right eye steep K value was associated with female gender (p<0.0001; odds ratio [OR] 2.21), Hispanic ethnicity (p=0.02; OR 0.90), Non-Hispanic White (NHW) ethnicity (p<0.0001; OR 1.36), Non-Hispanic Black (NHB) ethnicity (p<0.0001; OR 0.71), height in centimeters (p<0.0001; OR 0.95), and history of asthma (p=0.001; OR 1.22). In subgroup analysis of males and females, associations with NHW ethnicity, NHB ethnicity, height, and asthma remained significant. The association with Hispanic ethnicity remained significant in subgroup analysis of females but not in males.
Conclusions :
Dioptric corneal power did not differ significantly between right and left eyes. Dioptric corneal power demonstrated positive associations with female sex, NHW ethnicity, and history of asthma. Dioptric corneal power demonstrated negative associations with Hispanic and NHB ethnicities, as well as with height. Further research is needed to evaluate possible shared pathophysiologic mechanisms between corneal steepness and ethnicity, female sex, shorter height, and asthma.
This is a 2020 ARVO Annual Meeting abstract.