Pain sensitivity and autonomic nervous system parameters as predictors of dry eye symptoms after LASIK

• Published in: The ocular surface Vol. 19; pp. 275 - 281
• Main Authors: Levitt, Alexandra E., Galor, Anat, Small, Leslie, Feuer, William, Felix, Elizabeth R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2021
• Subjects: Autonomic Nervous System; Central sensitization; Chronic pain; Dry eye; Dry Eye Syndromes - diagnosis; Dry Eye Syndromes - etiology; Eye pain; Humans; Keratomileusis, Laser In Situ; LASIK; Neuropathic ocular pain; Pain; Pain sensitivity; Prospective Studies; Surveys and Questionnaires; Pain sensitivity; Dry eye; Autonomic nervous system; Eye pain; Central sensitization; Neuropathic ocular pain; LASIK; Chronic pain
• ISSN: 1542-0124; 1937-5913; 1937-5913
• DOI: 10.1016/j.jtos.2020.10.004

Differences in pain processing and autonomic function among patients have been implicated in the development of chronic pain after surgery. This study was designed to evaluate whether pain and autonomic metrics predict severity of chronic dry eye (DE) symptoms after LASIK, as there is increasing evidence that DE symptoms may be manifestations of persistent post-operative ocular pain. Secondary analysis of prospective randomized clinical trial. Patients were treated with either pregabalin or placebo. As no significant differences in DE symptoms were detected by treatment allocation at six months, all participants were grouped together for the present analyses. Subjects were evaluated pre-LASIK with regard to evoked pain sensitivity (utilizing quantitative sensory testing), autonomic metrics and DE and ocular pain symptoms (via validated questionnaires). Measures of DE and ocular pain were assessed post-LASIK, and the Dry Eye Questionnaire 5 (DEQ5) score 6-months after surgery was the primary outcome of interest. 43 individuals were randomized to pregabalin (n = 21) or placebo (n = 22). 42 completed the 6-month visit. Several baseline autonomic metrics correlated with 6-month post-operative DEQ5 scores, including lower systolic (r −0.37, p = 0.02) and diastolic blood pressure (r −0.32, p = 0.04). Ocular pain at 6 months was also negatively correlated with blood pressure (r −0.31, p = 0.047). The presence of painful aftersensations was a significant predictor of chronic DE symptoms at 6 months (mean DEQ5 scores: 8.0 ± 1.9 versus 5.0 ± 5.0, p = 0.009). Heightened parasympathetic tone and prolonged pain sensitivity measured prior to surgery predicted greater DE symptom severity 6 months after LASIK. NCT02701764.