Studies have suggested that chronic dry eye symptoms may be manifestations of “persistent postoperative ocular pain” after LASIK procedures. Furthermore, research also links differences in pain processing and autonomic function to the development of chronic pain after surgery. A recent study considered pain and autonomic metrics as predictors of chronic post-op dry eye symptoms and found a link.

The secondary analysis of a prospective clinical trial included 43 patients randomized to receive either pregabalin (n=21) or placebo (n=22). There were no significant differences in dry eye symptoms between the two groups. The researchers evaluated pain sensitivity pre-LASIK, as well as autonomic metrics, dry eye and ocular pain symptoms. Mean dry eye and ocular pain levels were assessed post-LASIK, including a Dry Eye Questionnaire 5 (DEQ-5) administered six months after the surgery.

The researchers found that baseline autonomic metrics, such as lower systolic and diastolic blood pressure, correlated with the six-month post-op DEQ-5 scores. Ocular pain at six months was negatively correlated with blood pressure. The researchers also noted that the presence of painful aftersensations was a significant predictor of chronic dry eye symptoms at six months. They concluded that “heightened parasympathetic tone and prolonged pain sensitivity measured prior to surgery predicted greater dry eye symptom severity six months after LASIK.”

Levitt AE, Galor A, Small L, et al. Pain sensitivity and autonomic nervous system parameters as predictors of dry eye symptoms after LASIK. The Ocular Surface. October 21, 2020. [Epub ahead of print].