Abstract
Purpose::
Little research has been done to investigate the relationship of ocular high order aberrations (HOAs) to pre-op patient characteristics such as ethnicity, gender, and eye dominance. The purpose of this study was to discover correlations between specific patient characteristics and HOAs.
Methods::
In a retrospective study, the ocular wavefront aberrations of 453 myopic virgin eyes from multiple clinical centers in the United States and the Asia-Pacific were analyzed. Wavefront exams were conducted on Hartmann-Shack aberrometers. The study population was 57% Caucasian, 38% Asian, and 5% "other." All wavefront diameters in this group were 5 mm or larger, and all were normalized to 5 mm before HOA analysis. Multivariate analysis was used to examine the relationships of higher order aberrations to ethnicity, gender, age, eye dominance, manifest refraction, and corneal curvature.
Results::
Ethnicity, especially when comparing Caucasian and Asian eyes, is a strong predictor for the HOA root mean square ( RMS) values (p<0.001). Age, manifest spherical power, and corneal astigmatism are also statistically significant predictors (p<0.001 to 0.05) of the amount of HOA RMS. Logistic regression analysis showed that Asians have a high risk ratio for flatter corneal curvatures (OR=1.57, p=0.01) and high corneal astigmatism (OR=6.6, p=0.00). On average, Asian corneas are 1.00 D flatter than Caucasian corneas. The average corneal astigmatism of Asians was 1.37 D compared to the average Caucasian corneal astigmatism of 0.69 D. Additionally, when age and pre-op refraction are controlled for, Asian eyes have a significantly higher probability of elevated RMS value on total HOA (OR=1.41e+10, p=0.00) as well as some high order terms.
Conclusions::
Our study found correlations between HOAs and patient ethnicity, HOAs and corneal astigmatism, HOAs and refractive errors, and HOAs and age. Asians are more likely to have flatter corneal curvature, more corneal astigmatism, and more HOAs than Caucasians. High corneal astigmatism may affect treatment outcome due to biomechanical response; while eyes with high pre-op HOAs were more likely to have reduced HOAs post-op. These findings suggest that different ethnicities may benefit from different treatment management, depending on their pre-op ocular characteristics.
Keywords: refractive surgery: optical quality