Efficacy of digital pupillometry for diagnosis of Horner syndrome.

Abstract

To evaluate the efficacy of digital pupillometry in the diagnosis of anisocoria related to Horner syndrome in adult patients.Retrospective, observational, case control study.Nineteen patients with unilateral Horner syndrome (Horner group) and age-matched controls of 30 healthy individuals with normal vision and neither optic nerve dysfunction nor pupillary abnormalities were included. Pupillary light reflex (PLR) of the Horner group and controls were measured by a dynamic pupillometer (PLR-200; NeurOptics Inc., Irvine, USA). Minimal and maximal (min/max) pupil diameters, latency, constriction ratio, constriction velocity, dilation velocity, and total time taken by the pupil to recover 75% of maximal pupil diameter (T75) were noted. PLR were measured at baseline in both groups and at 30-45 minutes later after 0.5% apraclonidine (Iopidine®; Alcon Laboratories, Fort Worth, TX, USA) instillation in the Horner group.The PLR parameters in the affected eye and inter-eye difference before and after 0.5% apraclonidine instillation.In the Horner group, pupil diameters and T75 showed significant difference between the affected eye and unaffected contralateral eye at baseline (all P 0.5 mm, or 2) T75 > 2.61 seconds in the affected eye, which showed a sensitivity of 94.7% and specificity of 93.3%. The diagnostic accuracy of apraclonidine testing showed a sensitivity of 84.6% and specificity of 92.3%.Digital pupillometry is an objective method for quantifying PLR. Baseline inter-eye difference in maximal pupil sizes and dilation lag measured by T75 was equally effective in the diagnosis of Horner syndrome compared to the reversal of anisocoria after apraclonidine instillation.