Low contrast visual acuity and glare susceptibility with different types of intraocular lenses

ABSTRACT

Assessment of quality of vision namely low contrast visual acuity and glare susceptibility with different types of intraocular lenses [IOLs] recently introduced in our market. The quality of vision with low contrast early treatment diabetic retinopathy study [ETDRS] visual acuity charts as well as glare susceptibility ratio [GSR] in levels of luminance for day light [Photopic] conditions. Best corrected visual acuity [BCVA] and tests for quality of vision were performed in cross-sectional pattern four weeks postoperative. The inclusion criteria were uneventful phacoemulsification IOL implantation in the bag. Eyes with significant posterior capsule opacification [PCO] and eyes with other associated ocular pathology were not included. Four classes of IOL materials were included; polymetylemetacrylate [PMMA], hydrophilic acrylic, second generation silicon and three designs of hydrophobic acrylic IOLs. Seventy eyes were included in the study with 10 eyes implanted by each group of IOL and 10 control eyes. The mean BCVA in 100% and 25% contrast targets was not statistically significant in different groups. In 100% contrast targets, the mean BCVA was 0.91 in PMMA, 0.87 in hydrophilic acrylic, 0.9 in Acrysof MA, 0.92 in Acrysof SA, 0.91 in califlex and 1.1 in the control group. 25% contrast targets, the mean BCVA was 0.72 in PMMA, 0.61 in hydrophilic acrylic, 0.65 in Acrysof MA, 0.69 in Acrysof SA, 0.65 in Sensar, 0.7 in Clariflex and 0.8 in control group. However in lower contrast steps [12.5% and 6%] only Acrysof SA and Clarifiex groups had mean BCVA [0.55 and 0.61 respectively in 12.5% contrast and 0.41 and 0.52 respectively in 6% contrast]. These were not significantly different from control group. The mean GSR in Acrysof SA group was 1.0 in 100% contrast, 1.09 in 25% contrast, 1.1 in 12.5% contrast and 1.2 in 6% contrast. The mean GSR in Clarifiex group was 0.92 in 100% contrast, 0.69 in 25%, contrast, 0.95 in 12.5% contrast and 1.0 in 6% contrast. These results were not significantly different from control group mean GSR [0.92 in 100% contrast, 0.89 in 25% and 12.5% contrast and 0.81 in 6% contrast]. Only hydrophobic acrylic IOL [Acrysof SA] and second generation silicon IOL [Clariflex] with high refractive index [RI] and protected edge designs had mean BCVA not significantly different from control group in all low contrast steps [25%, 12.5% and 6%]. Hydrophobic acrylic with non protected edge design [Acrysof MA] and those with relatively higher water content [Sensar AR[40]e] had mean BCVA that was significantly different from control in 12.5% and 6% contrast steps. Also the Acrysof SA and Clariflex besides Sensar AR[40]e had mean GSR that was not significantly different from control group and was stable with decreasing contrast steps. The small optic PMMA IOL had intermediate performance. The hydrophilic acrylic with square non protected edge had the lowest performance