Effects of different levels of intraocular stray light on kinetic perimetry findings.

Kazunori Hirasawa,Nobuyuki Shoji,Manami Tsuchiya,Karen Isono,Sanjoy Bhattacharya

doi:10.1371/journal.pone.0127159

Abstract

PurposeTo evaluate the effect of different levels of intraocular stray light on kinetic perimetry findings.MethodsTwenty-five eyes of 25 healthy young participants were examined by automated kinetic perimetry (Octopus 900) using Goldmann stimuli III4e, I4e, I3e, I2e, and I1e. Each stimulus was presented with a velocity of 3°/s at 24 meridians with 15° intervals. Four levels of intraocular stray light were induced using non-white opacity filter (WOF) filters and WOFs applied to the clear plastic eye covers of the participants. The visual acuity, pupil diameter, isopter area, and kinetic sensitivity of each meridian were analyzed for each WOF density.ResultsVisual acuity deteriorated with increasing WOF densities (p < 0.01). With a visual acuity of 0.1 LogMAR units, the isopter areas for III4e, I4e, I3e, I2e, and I1e decreased by -32.7 degree2 (-0.2%), -255.7 degree2 (-2.6%), -381.2 degree2 (-6.2%), -314.8 degree2 (-12.8%), and -59.2 degree2 (-15.2%), respectively; kinetic sensitivity for those stimuli decreased by -0.1 degree (-0.1%), -0.8 degree (-1.4%), -1.6 degree (-3.7%), -2.7 degree (-9.7%), and -1.7 degree (-16.2%), respectively. The pupil diameter with each WOF density was not significantly different.ConclusionKinetic perimetry measurements with a high-intensity stimulus (i.e., III4e) were unaffected by intraocular stray light. In contrast, measurements with the I4e, I3e, I2e, and I1e stimuli, especially I2e and I1e, were affected. Changes in the shape of the isopter resulting from opacity must be monitored, especially in cases of smaller and lower-intensity stimuli.

Highlights

Kinetic perimetry is generally performed using the Goldmann perimeter[1–3], which requires the examiner to manually control the moving stimulus
Visual acuity deteriorated with increasing white opacity filter (WOF) densities (p < 0.01)
With a visual acuity of 0.1 LogMAR units, the isopter areas for III4e, I4e, I3e, I2e, and I1e decreased by -32.7 degree2 (-0.2%), -255.7 degree2 (-2.6%), -381.2 degree2 (-6.2%), -314.8 degree2 (-12.8%), and -59.2 degree2 (-15.2%), respectively; kinetic sensitivity for those stimuli decreased by -0.1 degree (-0.1%), -0.8 degree (-1.4%), -1.6 degree (-3.7%), -2.7 degree (-9.7%), and -1.7 degree (-16.2%), respectively

Summary

Introduction

Kinetic perimetry is generally performed using the Goldmann perimeter[1–3], which requires the examiner to manually control the moving stimulus. Inherent examiner bias, based on variable skills of the examiners, reduces the accuracy and consistency of manual kinetic perimetry findings [4]. To remove this bias, a few automated kinetic perimeters have been developed[5–8]. When cataracts coexist with these diseases, changes in the visual field defects may indicate deterioration of the condition or cataract, leading to confusion. In such cases, it is important to evaluate the effect of opacity on kinetic perimetry findings.

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