AIM: To analyze the higher-order aberrations of anterior corneal surface in patients with subclinical keratoconus.

METHODS: Forty-three eyes with the diagnosis of subclinical keratoconus(KCS group, mean age 25.32±4.18 years)and 60 normal eyes(control group, mean age 24.63±4.82 years)were included in this study. Corneal higher-order aberrations in each eye were measured by OPD Scan ARK-10000. Root mean square(RMS)values were calculated for total higher-order aberrations(HOAs), total coma(TC), total trefoil(TT)and total spherical aberration(TS)in 3mm and 6mm central area. The aberrometric parameters were respectively compared between two groups by Student's t-test.

RESULTS: In 3mm central area, the RMS of corneal HOAs, TC, TT and TS were 0.424±0.175μm, 0.113±0.068μm, 0.262±0.132μm, 0.016±0.010μm respectively in KCS group, while those in control group were 0.310±0.093μm, 0.070±0.038μm, 0.244±0.106μm, 0.019±0.016μm respectively, the differences were statistically significant in HOAs and TC(t=3.896, 3.748; P=0.000, 0.000), except for TT and TS(t=0.740, 1.169; P=0.231, 0.124). In 6mm central area, the RMS of corneal HOAs, TC, TT and TS were 0.987±0.292μm, 0.642±0.260μm, 0.487±0.208μm, 0.292±0.145μm respectively in KCS group, while that in control group were 0.587±0.146μm, 0.252±0.113μm, 0.337±0.182μm, 0.271±0.065μm respectively, the differences were statistically significant in HOAs, TC and TT(t=8.273, 9.231, 3.800; P=0.000, 0.000, 0.000), except for TS(t=0.888, P=0.191).

CONCLUSION: The corneal higher-order aberration, especially TC, is significantly higher in subclinical keratoconic eyes than in normal eyes. It may be a potential diagnostic tool for subclinical keratoconus.