Post-Photorefractive Keratectomy Pain and Corneal Sub-Basal Nerve Density Publisher



Mohebbi M¹ ; Rafatnejad A¹ ; Mohammadi SF¹ ; Asnaashari K¹ ; Kasiri M¹ ; Heidarikeshel S¹ ; Askarizadeh F¹ Show Affiliations
Source: Journal of Ophthalmic and Vision Research Published:2017

Abstract

Purpose: The perceived and reported pain of patients receiving photorefractive keratectomy (PRK) widely varies. We assessed the potential role of the subbasal nerve plexus density as a predictor of postoperative pain level. Consecutive patients scheduled to undergo PRK at the Refractive Surgery Clinic of Farabi Eye Hospital, Tehran, were approached. Methods: Forty-nine myopic left eyes from 49 patients who consented to undergo scanning slit confocal microscopy assessments preoperatively were included. ImageJ (1.48v) was used to measure the captured subbasal nerve length. Postoperative pain intensity was assessed by the Visual Analog Scale (VAS) (score range: 0 for no pain to 10 for the maximum possible) on the next day of surgery. Results: The mean age of the patients was 27.55 (range: 19-40) years. The median reported pain level was 5. Approximately 32.7% of the subjects reported a pain score of 6 or higher. Mean nerve density was 19.54 (range: 14.34-24.73) mm/mm2. Nerve density was not correlated with the reported intensity of pain (P = 0.172). However, pain was correlated with the reported ocular discomfort, i.e., a pooled index of foreign body sensation, photophobia, burning sensation, and tearing (P < 0.001), and also with the pooled index of ocular inflammatory signs (conjunctival injection and eyelid edema) (P = 0.027). Conclusion: Crude density of corneal nerves may not be a good predictor of post-PRK pain while wearing bandage contact lenses. The predominant pain mechanism appears to be of an inflammatory nature (not nociceptive or neuropathic). © 2017 Journal of Ophthalmic and Vision Research Published by Wolters Kluwer - Medknow.