Abstract
Purpose: :
To evaluate the predictability of spherical aberration (SA) correction by 3 different aspheric and 1 spherical intraocular lenses (IOL).
Methods: :
One hundred twenty eyes of 92 cataract patients (36 males, 56 females, average age 68.6±9.1 years) who underwent cataract extraction and implantation of IOL were divided into 4 groups of 30 eyes per group (SN60WF, Alcon; ZA9003, AMO; FY60AD, Hoya; and SN60AT, Alcon). Pre- and postoperative visual acuity, higher-order aberration (HOA) of the cornea and the whole eye, contrast sensitivity function and pupil diameter (PD) under photopic and mesopic conditions were measured. The area under the log contrast sensitivity function (AULCSF) was calculated to represent visual function. Wavefront aberration was measured by ARK10000 (Nidek, Japan) and expanded up to the 8th order using Zernike polynomials. The HOA corresponding to the individual pupil diameter under photopic and mesopic conditions were calculated in each eye. The effect of HOA under physiologic PD on visual function was evaluated in 120 eyes. The relations between SA of the cornea and the whole eye, and PD were evaluated in each group.
Results: :
The mean postoperative PD was 2.9 ± 0.5 mm under photopic conditions and 3.6 ± 0.6 mm under mesopic conditions. Postoperative AULCSF was negatively correlated with SA under photopic condition without glare and mesopic conditions with and without glare (P=0.014, P<0.001 and P=0.01, respectively). Postoperative AULCSF was negatively correlated with the root mean square (RMS) of HOA under photopic conditions with and without glare (P=0.02 and P=0.02, respectively), however there were no significant correlations between RMS of HOA and AULCSF under mesopic conditions (P=0.11 and P=0.14). Under mesopic conditions, there were positive correlations between the postoperative SAs of the cornea and the whole eye in eyes with 3 aspheric IOLs with different regression coefficients (β=0.39 for SN60WF, β=0.38 for ZA9003 and β=0.58 for FY60AD), whereas there was no significant correlation in eyes with SN60AT. The differences of the cornea and the whole eye were significantly positively correlated with the PD in eyes with aspheric IOLs, whereas not correlated in eyes with SN60AT.
Conclusions: :
The postoperative SA has important effect on visual function under individual natural pupil conditions and its suppression improves visual function after cataract surgery. The amount of SA correction by aspheric IOLs varies on IOL type. The selection of aspheric IOLs according to the patient’s corneal SA and PD may enable customizing the postoperative SA in each patient.
Keywords: aberrations • intraocular lens • cataract