Use of RAPDx device with optic nerve disease
Reviewed by Claire Howard

The authors have previously reported on use of the RAPDx device for evaluating relative afferent pupillary defects (RAPD). RAPDx objectively determines the magnitude of RAPD by presenting light stimuli alternately to pairs of eyes with laterality. The parameters of amplitude score and latency score in RAPDx are used to calculate RAPD using log units. The amplitude score is obtained by determining the percentage of constriction of both eyes, whereas the latency score by determining the latency of both eyes. This paper details RAPD evaluations in patient with optic nerve disease, using the previously reported standard values of the amplitude and latency scores. Twenty-eight patients with optic nerve disease were recruited and compared to previously reported data from 84 healthy controls. Amplitude and latency scores were measured using the RAPDx and mean values compared between both groups. In addition, this data was evaluated for correlation with visual acuity and the critical flicker fusion frequency in the optic nerve disease group. Results showed significantly higher scores in the optic nerve disease group than in the control group, for both parameters. The authors conclude that the amplitude and latency scores determined using RAPDx are useful in evaluating RAPD, in particular the standard value of the amplitude score and that future studies should further investigate disease severity, stage and type using a greater sample size.

Evaluation of relative afferent pupillary defect using rapdx device in patients with optic nerve disease.
Satoua T, Ishikawaab H, Asakawab K, et al.
NEURO-OPHTHALMOLOGY
2016;40(3):120-4.