Effect of retinal stray light on visual function

Session Details

Session Title: Imaging

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 09:39

Venue: Capital Hall B

First Author: : M.Van der Mooren THE NETHERLANDS

Co Author(s): :    R. Rosén   P. Piers   L. Lundström        

Abstract Details

Purpose:

The aim of this study is to show the effect of retinal stray light on visual function

Setting:

KTH Royal Institute of Technology, Stockholm, Sweden

Methods:

Six photographic filters were used to induce retinal stray light in two subjects varying from levels caused by glistenings present in the bulk of intraocular lenses to cataract levels. The retinal stray light levels were characterized using the C-Quant and then verified with optical bench measurements. Three methods were used to measure the visual function: contrast sensitivity with and without a glare source, the Rostock Glare Perimeter(RGP) and a modified RGP. The Contrast Sensitivity Function (CSF) was measured from 3 m distance on a screen with a mean luminance of 35 cd/m² with small incremental steps, both in spatial frequency and in contrast sensitivity. The glare source was at 2.5 degrees with illuminance of 12 lux at eye level. With the RGP a central glare source at 3 m distance illuminated the eye with approximately 0.5 lux and we measured the size of the halo with a 0.13 degree sized white marker having 10 cd/m² luminance. This setup was modified by fixating the marker to an angular position of 2.5 degrees, and with a forced choice detection task the luminance threshold level was determined. The outcomes of the C-quant were compared to the outcomes of these three methods.

Results:

The in vitro measured light scatter levels of the filters compared very well to the induced retinal stray light values measured by the C-Quant. Increase in stray light of 0.1 in log(s) corresponds to the effect of glistenings in intraocular lenses. With an increase of 0.1 log(s) in retinal stray light, the contrast sensitivity decreased on average 8% without a glare source and 20% with a glare source. The halo size increased by 20% and the required luminance at 2.5 degrees increased by 66% per 0.1 log(s) increase in stray light.

Conclusions:

Retinal stray light correlates strongly with the outcomes of the methods used to measure visual function. Levels of retinal stray light as induced by glistenings have measurable impact on visual function.

Financial Interest:

One or more of the authors... is employed by a forNONEprofit company with an interest in the subject of the presentation, One or more of the authors... receives nonNONEmonetary benefits from a company producing, developing or supplying the product or procedure presented.