Chromatic Pupillometry in Patients with Retinitis Pigmentosa

Objective To evaluate the chromatic pupillary response as a means of assessing outer and inner retinal function in patients with retinitis pigmentosa (RP). Design Evaluation of diagnostic technology. Participants Thirty-two patients with RP and visual loss and 43 normal subjects. Methods Patients were tested with a chromatic pupillometer using red and blue lights (1, 10, and 100 cd/m2 ), and their pupil responses were compared with those from 43 normal subjects (reported previously). Visual field and electroretinography (ERG) results were examined and compared with the pupil responses. Main Outcome Measures The percent pupil contraction of the transient response to a low-intensity (1 cd/m2 ) blue light and high-intensity (100 cd/m2 ) red light and the sustained response to a high-intensity blue light was calculated for 1 eye of each subject. Results The pupil responses to red and blue light at all intensities were recordable in all patients except 1, whose pupil responded only to bright blue light. There was a significant difference of the pupil response between patients with RP and normal subjects in testing conditions that emphasized rod (1 cd/m2 blue light) or cone (100 cd/m2 red light) contribution ( P