Objective and subjective outcomes in comparing three different aspheric intraocular lens implants with their spherical counterparts

Abstract

Purpose To look for objective and subjective differences between three types of aspheric intraocular lens implants and their spherical counterparts. Methods Thirty patients were randomised to receive one of six lens implants including three aspheric lenses and their spherical counterparts. Pre and postoperative testing was carried out including visual acuity, contrast sensitivity and wavefront analysis. All patients were asked to fill in a visual function questionnaire (modification of cataract TyPE) to assess subjective differences in visual quality. Results There was no significant difference between groups for best-corrected visual acuity. Contrast sensitivity testing showed the Tecnis lens to perform better than the Cee-on Edge in all lighting conditions with significant differences at 3 and/or 6 cycles/degree in three out of four lighting conditions. No significant differences in contrast sensitivity were seen between the other lens pairs. All aspheric lenses showed less spherical aberration than their spherical pairs with statistical significance reached in two out of three pairs (the Ceeon Edge vs Tecnis, and Acrysof Natural vs IQ). The questionnaire revealed no evidence of improved subjective vision with the aspheric lenses compared to the spherical lenses. Conclusions This pilot study concurs with previously published trials in showing decreased spherical aberration and improved contrast sensitivity with aspheric lenses compared to spherical lenses. There was no evidence that the patients implanted with aspheric lenses rate their quality of vision higher than those implanted with spherical lenses. Study numbers were small and larger numbers may be required to demonstrate statistical differences in subjective data.

Customized aspheric intraocular lenses calculated with real ray tracing

“…In comparisons of the Tecnis Z9000 or Z9001 aspheric IOL and spherical IOLs, a few studies 16,19 found an increase in corrected distance visual acuity (CDVA), and most report similar outcomes. 15,[20][21][22][23]25,29,30,38,43,44,[47][48][49][50]77 Similar CDVAs were also reported for the AcrySof IQ SN60WF IOL 29,[32][33][34][35][36][37][38][39][40][41]45,46 and other aspheric IOLs. 29,31,37,38 The results in studies of contrast sensitivity are not as consistent as the visual acuity results.…”

Effect of spherical aberration on visual function under photopic and mesopic conditions after cataract surgery

“…Aspheric IOLs were designed to compensate for the positive spherical aberration of the cornea. Although some studies 1,4,13,[22][23][24][25][26][27] report that the reduction in postoperative spherical aberration by aspheric IOLs improved visual function, other studies 21,37 report no significant difference in visual function between spherical IOLs and aspheric IOLs. The limitations of these studies were a fixed pupil diameter and a lack of assessment of individual visual function and spherical aberration considering individual pupil diameter; this is important because corneal spherical aberration varies widely in the population 7 and pupil diameter, which affects the amount of spherical aberration, also widely among individuals.…”

“…The limitations of these studies were a fixed pupil diameter and a lack of assessment of individual visual function and spherical aberration considering individual pupil diameter; this is important because corneal spherical aberration varies widely in the population 7 and pupil diameter, which affects the amount of spherical aberration, also widely among individuals. 28 Moreover, studies 1,4,13,[22][23][24][25][26][27] show that aspheric IOLs improve contrast sensitivity over that with spherical IOLs; however, the amount of spherical aberration to optimize the visual function remains unknown. We believe it is imperative to assess the efficacy of correcting spherical aberration by evaluating the relationship between individual spherical aberration, HOAs, and visual function.…”

“…Aspheric IOLs were designed to compensate for the positive spherical aberration of the cornea. Studies 1,4,13,[22][23][24][25][26][27] report that the reduction in postoperative spherical aberration by aspheric IOLs improved visual function. These studies compared spherical aberration after instillation of cycloplegic agents (analysis diameter of 4.0 to 6.0 mm) and visual function between aspheric IOLs and spherical IOLs.…”

Feasibility of spherical aberration correction with aspheric intraocular lenses in cataract surgery based on individual pupil diameter

“…However, results in recent studies show discrepancies in terms of whether aspheric IOLs provide better postoperative visual function than spherical IOLs. 1,4,13,[20][21][22][23][24][25][26][27] These studies are limited by the use of a fixed pupil diameter (from 4.0 to 6.0 mm) and by not including an assessment of individual visual function when evaluating the amount of spherical aberration according to individual pupil diameter. In some patients with small pupils (eg, 3.0 mm) under mesopic conditions, the spherical aberration is too small to affect postoperative visual function.…”