Abstract
Purpose: :
The prescription of colored filter lenses is a regular feature of low vision rehabilitation. Manufacturers recommend colored filter lenses based on primary ocular diagnosis. Nonetheless, many vision rehabilitation specialists evaluate a wider array of colored filter lenses in a trial-and-error fashion before prescribing. This technique can be time-consuming. The purpose of this study was to investigate whether following the manufacturer’s recommendations would be more efficient. This was done by determining whether a group of patients selected a colored filter lens recommended by the manufacturer for their primary diagnosis even when offered alternative options. The objective benefits of colored filter lenses are controversial in the literature. For this reason, the effect of the prescribed colored filter lenses on both qualitative and quantitative vision was also measured.
Methods: :
The best corrected visual acuities and contrast sensitivity of eight patients with visual impairment were measured. The primary diagnosis of each patient was one of three common ocular conditions: age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy. Each patient was asked to rank their preference for five colored filter lenses selected from the recommendations made by NoIR Medical Technologies for the three diseases. The lenses included the U68 (light orange), U50 (yellow), U32 (grey-grey-green), U88 (light plum) and U40 (light amber). These colored filter lenses are available as UVShield fitovers, lenses designed to fit over the patient’s glasses. The patients were not told which lenses had been recommended for their primary diagnosis. Best corrected visual acuity and contrast sensitivity were re-measured once a fitover had been chosen.
Results: :
All subjects identified one pair of colored filter lenses as better than the other four choices. Four of eight chose a filter that was on the NoIR Medical Technologies list of recommendations for that primary diagnosis. Only two of eight demonstrated an improvement in objective measurements of vision (one in visual acuity, and the other in contrast sensitivity).
Conclusions: :
Only half the patients studied chose a pair of colored filter lenses that was on the list of the manufacturer’s recommendations for their primary diagnosis. Subjective trial-and-error of a variety of colored filter lenses appears to be the best approach. The vision rehabilitation specialist should refrain from prescribing lenses based solely on the manufacturer’s recommendations.