A Study of higher order aberrations in young myopia and myopia astigmatism by iTrace system

Objective To analyze higher order aberrations in young myopia and myopic astigmatism,and to investigate the value of application of iTrace application of wavefront aberrations and the relevant factors of them.Methods Using a Ray-tracing method,138 young myopic and astigmatism eyes were evaluated.The root mean square(RMS)values of higher order aberrations for each subject with pupil diameters of 5mm were calculated.The subjects were divided into following groups:group A,40 eyes(low myopia≤ -6.0D,astigmatism≤ - 1.0D),group B,38 eyes(low myopia,astigmatism＞- 1.0D),group C,30 eyes(high myopia＞-6.O0,astigmatism≤-1.0D),group D,40 eyes(high myopia,astigmatism＞-1.0D).Results RMS values in all groups,there was significant difference between 4 groups for total and low order aberrations.However,there was no difference with high order aberration(HOA)between groups but coma.The significant difference existed between group A and C for vertical coma in corneal HOA.The analysis of factors associated with aberration show myopia correlated significantly with spherical and coma; astigmatism only display relationship with coma;corneal curvature and axial length will not affect HOA.Conclusions The main total and corneal HOA difference between groups were coma aberrations which was liner correlated with myopia and astigmatism. Key words: iTrace system; Myopia; Astigmatism; Refraction; Waveffont