Abstract
Purpose :
An exploratory prospective study to determine the test-retest reliability and diagnostic accuracy of a binocular optical coherence tomography (OCT) prototype for the assessment of pupil parameters including the detection of relative afferent pupillary defect (RAPD).
Methods :
Fifty participants with RAPD confirmed using the swinging flashlight test recruited from neuro-ophthalmology, glaucoma, and retina clinics (mean age 49.6 years), and 50 healthy controls (mean age 31.3 years), twice underwent an automated pupillometry exam using the binocular OCT prototype. This is an automated system that simultaneously captures OCT images of both anterior segments including the iris-pupil plane whilst delivering a controlled bright white stimulus on the display screens within the device. Participants also underwent a single exam on the Konan RAPDx, an automated infrared pupillometer. Pupil parameters such as maximum and minimum pupil diameter, and anisocoria were measured. The log ratio of the constriction amplitude was used to determine the magnitude of RAPD. A physiological RAPD was considered to be within ±0.5 log units on both devices.
Results :
All subjects completed the binocular OCT pupillometry exam. One healthy control and one participant with RAPD did not complete examination on the RAPDx due to unreliable detection of the pupil. The intraclass correlation coefficient for OCT-derived maximum pupil diameter, minimum pupil diameter, anisocoria, and constriction amplitude was 0.95 (95% confidence interval [CI] 0.94-0.96), 0.93 (CI: 0.91-0.94), 0.97 (CI: 0.95-0.97), and 0.88 (CI: 0.85-0.90), respectively. The RAPDx had a sensitivity of 82% and a specificity of 94% for RAPD detection, whereas the binocular OCT had a sensitivity of 74% and specificity of 86%. The diagnostic accuracy of the RAPDx and binocular OCT was 88% (CI: 80-94%) and 80% (CI: 71-87%) respectively. Bland-Altman analysis revealed a mean difference of -0.02 between the RAPDx and binocular OCT (95% limits of agreement -1.72 to 1.69).
Conclusions :
Binocular OCT-derived pupil parameters such as pupil diameters and anisocoria had excellent test-retest reliability. Diagnostic accuracy of RAPD was inferior to the RAPDx and is likely related to factors such as eye movement during OCT capture. However. as OCT becomes ubiquitous in eye care, OCT-derived measurements may provide an efficient and data rich method of quantifying and imaging the pupil responses.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.