Contrast sensitivity and glare contrast sensitivity of spherical and aspherical intraocular lens at different pupil diameters

Objective To compare the differences of contrast sensitivity(CS)and glare contrast sensitivity(GS)of spherical and aspherical intraocular lens(IOL)at different pupil diameters:2.0-2.5 mm,4-5 mm and 8 mm.Methods Sixty eyes of 48 patients with age-related cataract,which having phacoemulsification or maneuver nuclear fraction through small incision,were assigned to receive a spherical or aspherical foldable intraocular lens.They were divided into two groups according to the different types of IOL:spherical IOL group(35 eyes)and aspherical IOL group(25 eyes).CS and GS of the two groups were measured at different pupil diameters of 2.0-2.5 mm,4-5 mm and 8 mm with low spatial frequency(3 cycle/degree,cpd),middle spatial frequency(6 cpd)and high spatial frequency(12 cpd,18 cpd)one month postoperatively.Results In spherical IOL group,there were statistically significant differences between CS and GS at 6 cpd,12 cpd when pupil diameter was 4-5 mm,and there were statistically significant differences between CS and GS at all spatial frequencies when pupil diameter was 8 mm.In aspherical IOL group,there were no statistically differences between CS and GS at all spatial frequencies under three pupil conditions.Comparison of spherical and aspherical IOL:the difference of CS was significant between them at high spatial frequencies when pupil diameter was 2.0-2.5 mm and 5 mm;The difference of GS at low spatial frequencies and the difference of CS and GS at middle spatial frequencies were significant between two groups when pupil diameter was 8mm.Conclusion In spherical IOL group,with increasing of pupil diameter,the values of CS and GS decreases,and the bigger the pupil diameter is,the more obvious decrease of CS when affiliated with glare is.In aspherical IOL group,the decrease of CS under glare conditions is not happen significant at any pupil diameter,and the bigger the pupil diameter is,the more obvious the function of compensating positive spherical aberration and reducing spherical aberration is.