Real-Time Pupil Assessment by Spectral Domain Optical Coherence Tomography in Relative Afferent Pupillary Defect and Comparison with Swinging Flash Method in Clear and Hazy Cornea

Abstract

Abstract Purpose: To evaluate the real-time pupil diameter in relative afferent pupillary defect (RAPD) with spectral domain optical coherence tomography (SD-OCT) and compare it with the swinging flashlight method (SFM). Methods: In this, prospective, non-randomized, comparative case series, patients with RAPD with clear and hazy cornea were included. The normals with no RAPD have been taken as controls. The pupillary responses were noted in both eyes and the difference in pupil sizes (in mm) was recorded using the SD-OCT (Cirrus 5000, Zeiss) and correlated with SFM. OCT images were evaluated by Image J analysis (Wayne Rasband and National Institute of health). Baseline pupil size, the amplitude of constriction, response to external light and comparison with control eyes and hazy cornea were analysed. Results: Overall, 102 eyes of 51 study patients were imaged. OCT was able to detect RAPD in 100% of eyes. There was a significant difference between the fellow and affected eye (P < 0.05) pupil diameter in the study group. The affected eye had a larger pupil diameter than that of the fellow. There was a significant difference (P < 0.05) between the amplitude of pupil constriction between the fellow and the affected eye. There was a significant difference in the pupil size with respect to the severity of RAPD (P < 0.05). OCT was able to detect RAPD in 13.7% of hazy corneas. There was a statistical correlation between the SFM and OCT grading (P < 0.001, r = 0.771). On comparison with normal controls, there was a significant difference in the amplitude of constriction and basal pupil size. Conclusion: SD-OCT can be used objectively to detect and document RAPD in clear and hazy corneas.