To evaluate the correlation between refractive, corneal and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates

This cross- sectional descriptive-analytical study consisted of 200 patients who were referred to the Farabi hospital for refractive surgery. Refraction, topography and aberrometry were done to determine refractive, corneal and residual astigmatism and HOA for all of participants and statistical analyses were performed using software SPSS version 20.

Overall, 200 subjects with average age of 28.2±6.24 years (range 20-52 y) participated in this study; among which (250) 62.7% of cases were female; According to spherical equivalent 375 eyes (94.2%) were myope and 13 eyes (3.3%) were hyperope and 315 eyes (78.9%) were had refractive astigmatism more than 0.75 D. mean spherical equivalent refractive errors in myopic group was -3.59±1.95 D (range, -0.54 to -10.22D) and in hyperopic group was 2.72±0.97 D(range, 0.67 to 4.23D) and mean astigmatism was 1.97±1.3 D in myopic group and was 1.3±1.37 D in hyperopic group. The mean of higher order aberrations (RMS) was 0.38±0.15 µm in all cases. It was 0.38±0.15 µm in myopic group and 1.3±1.37 µm in hyperopic group which was correlated with increase in SE amount in both groups. (p<0.001) There was significant statistical correlation between corneal astigmatism and HOA (p=0.037) and there was also significant correlation between residual astigmatism and HOA (p=0.025). There was marginal correlations between refractive astigmatism and HOA (p=0.09).

There are significant correlations between refractive, corneal and residual astigmatisms and higher order aberrations. Therefore, to achieve better vision and prevention of halos and glare and night vision problems after surgery, we recommend to evaluate all aberrations in refractive surgery candidates especially in patients who have high astigmatism and consider customized ablations if needed.