Abstract
Purpose :
Ocular surface pain can be induced by nociceptive, neuropathic, or nociplastic factors, but few diagnostic tests examine nerve status as it relates to ocular pain. Aftersensations (AS) are sensations that persist after the termination of a stimulus and can be used to understand abnormal somatosensory system processing. This study aimed to examine relationships between the presence of AS and ocular pain characteristics.
Methods :
A prospective study was conducted at the Miami Veterans Administration in individuals with and without ocular pain. Dry eye (DE) and pain-focused questionnaires were completed (5-item Dry Eye Questionnaire [DEQ5], Ocular Surface Disease Index [OSDI], Numerical Rating Scale [NRS], and Neuropathic Pain Symptom Inventory modified for the eye [NPSI-Eye]). All individuals underwent an ocular surface examination and a somatosensory testing protocol which included prolonged (~5 sec) thermal noxious stimulation (cold and hot) at two sites (forehead and forearm), followed by ratings of AS. There were four AS outcome measures (15- and 30-sec after termination of stimulus and rating of unpleasantness and pain intensity [0-100 NRS]) for each condition. Ratings >0 were grouped as a positive AS.
Results :
Mean age of the study population (n=272) was 59±9.3, 89% self-identified as male, 38% as White, and 24% as Hispanic. Considering all 16 AS metrics, the presence of unpleasant sensation at 15 seconds to a hot forearm stimulus was most closely associated with DE (DEQ5, β=0.19, p=0.02) and ocular pain (NRS, β=0.16, p=0.03) metrics. Those with positive unpleasant AS at this site also had higher OSDI, NPSI-Eye, DE discordance, and corneal sensitivity scores versus those who did not report this AS. DE signs were not significantly related to this AS.
Conclusions :
The presence of 15-sec unpleasant AS due to a hot stimulus at a site remote from the eye (forearm) was associated with neuropathic ocular pain symptoms, but not tear film abnormalities. Presence of AS may be a useful test to identify when nervous system abnormalities contribute to ocular symptoms with potential implications for therapeutic algorithms.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.