Abstract
Purpose: :
Intraocular higher order aberrations (HOA) caused by irregularities in the crystalline lens increase with age leading to deterioration of visual performance. Since the influence of axial length (AL) on HOA is unclear, we investigated the effects of age and AL on intraocular HOA.
Methods: :
Subjects comprised 273 right eyes of males (40.7±7.9 yrs old) with no eye problems but refractive error. AL was measured with an IOL Master (Zeiss) and wavefront aberration with the Hartmann-Schack Aberrometer (KR-9000 PW, Topcon) for a 6-mm pupil.
Results: :
Mean AL and refractive errors were 25.22±1.25mm and -3.02±2.58D, respectively. AL tended to be shorter with age (AL= 25.9 - 0.016/Age), but no significant correlation was observed P=0.106). Ocular and corneal total HOA increased significantly with age (P<0.001 and P<0.01), and intraocular HOA decreased (P<0.05). Among types of intraocular HOA (spherical, trefoil, coma, tetrafoil, and 2nd astigmatism), only spherical was correlated with age. Negative aberration decreased with age (P<0.001), and the absolute value showed a notable positive correlation with total intraocular HOA. (r=0.433, P<0.001). Ocular, corneal and total intraocular total HOA all correlated negatively with AL-the longer the AL, the less the HOA (P<0.001). Only coma type intraocular HOA was significantly correlated with AL (P<0.001). There was a remarkable positive correlation between intraocular total HOA and coma aberration (r=0.839, P<0.001). Multiple linear regression analysis of intraocular total HOA, age and AL, showed a significant correlation among them (multiple correlation coefficient 0.277). The effect of AL on aberration was 1.8 times larger than that of age (fraction of standardized partial regression coefficient : AL/Age = -0.263/-0.145).
Conclusions: :
AL has more effect on intraocular HOA than age has. Decrease of coma aberration, especially, is associated with AL.
Keywords: aberrations • aging: visual performance