To the Editor.
—We are fascinated by the material presented in the case report by Forman et al.1 They described a patient with both Parinaud's syndrome and a large relative afferent pupillary defect (RAPD), with no other evidence of abnormal anterior visual pathways. This was likened to a case previously described by Ellis.2 We believe this case demonstrates not a midbrain afferent pupillary defect, but rather a type of contraction anisocoria (which develops with light stimulation) not previously described.In the swinging flashlight test, the direct reflex of one eye is observed and, after a rapid movement of the light source to the other eye, the light reaction in the second eye is noted. The second eye has consensually constricted, and any reaction is due to a difference between its direct response and its consensual response (during stimulation of the first eye). Relative afferent pupillary defect, then, appears
Sinoff SE, Rosenberg M. Relative Afferent Pupillary Defect With Normal Visual Function. Arch Ophthalmol. 1992;110(4):447-448. doi:10.1001/archopht.1992.01080160025005