Comparison Of Fundus-viewing Quality Through Various Intraocular Lenses

Abstract

Purpose: : Many kinds of intraocular lenses (IOLs) are available, but the quality of vision during vitrectomy with IOL implantation has not been well documented. In this study, we aimed to clarify differences of fundus-viewing quality by quantitating fundus images taken through various IOLs.

Methods: : We used an artificial model eye (Eyetech Co, USA) with a 100 dot/cm2 grid pattern at the fundus. An IOL was engaged properly and was exchangeable. An ophthalmic microscope with a CCD camera was used to capture fundus images through the IOLs. Initially, an aphakic fundus image was taken and then 3 images were taken through 11 different IOLs. The IOLs tested were X-70, X-60 (Santen), AR40e, ZA9003 (Abott), SA60AT, SN60WF (Alcon), VA60BBR, VA65BB, PY60R, PY60AD, and VA70AD (HOYA). ZA9003, SN60WF, PY60AD, and VA70AD were aspherical (Asph) and all other IOLs were spherical (Sph). X-70 and VA70AD had a 7.0 mm optics diameter (OD), VA65BB had a 6.5 mm OD and the rest had a 6.0 mm OD. All images were processed using Photoshop 4.0 software (Adobe Co, USA). The images were evaluated as follows: 1) the number of dots visible through the lens (visible area), 2) the number of dots obscured (blur test), and 3) the area that was clearly visible (effective visual area). The aphakic fundus image was merged with the fundus images taken through the IOLs and the number of distorted dots that were not merged were counted (distortion test). ANOVA and a t-test were used for statistical analysis.

Results: : The visible area was largest in the X70 compared to the other IOLs (p<0.0001). Z9003 gave the worst results in the blur test (p<0.0001) and X-60 and AR40e were worst in the distortion test. The effective visual area was largest in the X-70 and VA70AD IOLs (p<0.0001). Asph IOLs statistically had less distortion (p<0.0001) but worse blur compared to Sph IOLs (p=0.0355). IOLs with larger optics always had a larger visible area (p<0.0001) and effective visual area (p<0.0012).

Conclusions: : Large OD IOLs had a bigger visual area and had better results in distortion and blur tests. Asph IOLs showed less distortion compared to Sph IOLs, but the quality of vision based on the blur test and effective visible area did not exceed that of spherical IOLs.

Keywords: intraocular lens • imaging/image analysis: non-clinical • vitreoretinal surgery