Automated Photosensitivity Assessment in Achromatopsic and Healthy Subjects

Abstract

 

Purpose

 

To assess and compare the photosensitivity discomfort threshold in Achromatopsic and healthy subjects using the 2^nd Generation BPEI Photosensitivity Tester.

 

Methods

 

The 1^st Generation instrument (Aguilar MC et al, IOVS. 2014; 55: E-Abstract 4108 and Alawa K, IOVS. 2014; 55: E-Abstract 4109) was modified to comprise a bi-cupola concave light array panel with 210 white LED’s that are either manually controlled with a knob or computer controlled. The light intensity ranges from 1-32,000 lux at 50 cm. The instrument has two testing modes; one for subjects with normal light tolerance, the other has an enhanced mode for subjects having low light tolerance. The audio prerecorded testing instructions can be provided in four languages (English, Spanish, French, and Portuguese). The automated instrument varies the intensity of the light stimuli and the subject is instructed in their preferred language to indicate if it is uncomfortable by pressing a hand-held button. The testing is complete after 10 response reversals, from which a predicted photosensitivity threshold is calculated.<br /> <br /> Thus far, seven Achromatopsic subjects (5 females and 2 males, age = 14.3±6.0) and eleven healthy subjects (5 females and 6 males, age = 31.9±8.5) were tested under an IRB approved protocol. Prior to testing, the subjects rested during a 5 min. adaptation period in the examination room illuminated with 4 lux. Ambient conditions are monitored utilizing: humidity, temperature, and lux meters.

 

Results

 

Seven Achromatopsic subjects were found to have a mean predicted photosensitivity threshold of 0.75±0.66 log(lux). Eleven healthy subjects were found to have a mean predicted photosensitivity threshold of 3.32±0.66 log(lux). A one-way analysis of variance was performed and there is a statistically significant difference (p<0.0001) in the threshold of photosensitivity experienced between the Achromatopsic and healthy subject groups.

 

Conclusions

 

The autonomous 2^nd Generation BPEI Photosensitivity Tester can assess a wide range of photosensitivity thresholds by detecting, quantifying, and recording the individual differences in sensory capabilities. Ongoing studies are being conducted in order to better understand the wide range of photosensitivity thresholds.  

 

Figure. 2^nd Generation BPEI Photosensitivity Tester