Abstract
Purpose: :
To determine whether pupillary light reflex (PLR) can serve as an indicator of photoreceptor function in patients with advanced typical retinitis pigmentosa (RP)
Methods: :
Dark-adapted transient PLR elicited by blue and white light over an intensity range of 4 log units were performed in 27 eyes of 19 patients with advanced RP, we also characterized fundus autofluorescence (AF) patterns and scotopic sensitivity in these patients. For qualitative analysis, we investigated whether PLR thresholds correlated with AF patterns as well as scotopic sensitivity. Quantitative analysis was further investigated, which included correlation between RPC elicited by blue light ≤ -1 log cd/m2 and area of abnormal ring or central AF, correlation between relative pupillary contraction (RPC) elicited by white light and perimetric mean sensitivity.
Results: :
RLR of all patients showed varying degrees of threshold elevation and relative afferent pupil defects. We classified three types of abnormal fundus AF: abnormal ring AF, abnormal central AF, and fragmentary AF. Pupillary thresholds were largely consistent with patterns of AF and scotopic sensitivity. Rod mediated RPC did not correlate with the area of the abnormal ring AF (P > 0.05), but correlated with area of abnormal central AF (P < 0.05). RPC at white stimulus of -0.3,0.7 log cd/m2 was significantly correlation to mean sensitivity of perimetry.
Conclusions: :
Chromatic PLR testing is a powerful technique in assessment of photoreceptor dysfunction. The high correlation with AF and dark-adapted perimetry, suggests that the key to quantify photoreceptor function by transient PLR is to optimize a suitable light intensity.
Keywords: pupillary reflex • photoreceptors: visual performance • visual impairment: neuro-ophthalmological disease