Use of the RAPDx device to evaluate efficacy of treatment in patients with optic nerve disease
Reviewed by Claire Howard

The RAPDx objectively determines the RAPD magnitude by alternately presenting light stimuli to each eye and deriving amplitude and latency scores. The authors of this paper evaluated the amplitude and latency scores from the RAPDx together with other ophthalmic investigations for patients with optic nerve disease, before and after treatment. Following treatment, the visual acuity and visual field defect had resolved in all patients. However, in all patients, the amplitude and latency scores after treatment were lower. Both scores for evaluation of RAPD by RAPDx correlated with subjective examinations and were useful for the evaluation of the efficacy of treatment. The authors show that RAPD can be detected after treatment related recovery in visual acuity and visual field loss, and this can be quantitatively assessed using the RAPDx. This study has limitations in that the patient numbers were small and larger studies are warranted to further investigate the use of RAPDx to demonstrate the efficacy of treatment in optic nerve disease. 

Evaluation of a relative afferent pupillary defect using the RAPDx device before and after treatment in patients with optic nerve disease.
Satou T, Ishikawa H, Goseki T, Asakawa K.
NEURO-OPHTHALMOLOGY
2018;42(3):146-9.