The Effect Of Zonal Multifocal Lenses With Distance And Near Design On Visual Field Parameters

Abstract

Aim : The aim of this article is to evaluate the visual field of healthy young subjects and determine the stability of commonly observed parameters, before and after fitting with zonal multifocal lenses with distance and near design. Materials and M ethods: Thirty young subjects (20-26 years) with equal sex distribution and no eye problems were prospectively included in the study. The subjects had no need and never wore refractive correction on the tested eye (mean refraction ±0.12D). After meticulous eye examination, visual field 24-2 Threshold test (Humphrey Field Analyser 3 (HFA3) model 860 by Zeiss, version 1.3.1.2) was performed first on the fellow eye and then on the tested eye in order to gain experience. The test was repeated 3 times per eye. [AU1] Strategy was standard SITA, background 31.5 asb and III white stimulus. The test was performed 30 minutes after insertion of the zonal multifocal lens with distance design, and the methodology repeated with a near design lens [AU2] (Biofinity multifocal, Cooper Vision). The outcome measures included hemifield test (HT), visual field index (VFI), mean deviation (MD) pattern standard deviation (PSD), and total and pattern deviation (TD &PD) only for <1.0 and <0.5. The primary outcome measures were MD and PSD. Statistical analysis was performed using SPSS v.21 package. Results: Thirty eyes (equal number of left and right eyes) were tested. None of the tests presented more than one fixation loss and more than 3% false positive or negative responses. The automatic hemifield test was borderline in 10 eyes at the baseline examination and this number increased to 13 for distance design lenses and 16 for near design lenses. For the 6 cases of the last group the change was a mean of -2.91dB, and statistically significant (p=0.001). The rest of the outcome measures were with slight, not statistically significant change, except for MD which was similar to the baseline (1.29) for the distance design lenses (1.35), but significantly (p=0.003) higher for the near design multifocal lenses (1.87).