Mechanisms of corneal pain and implications for postoperative pain after laser correction of refractive errors

Objective: The cornea is the target of most surgeries for refractive disorders, as myopia. It is estimated that almost 1 million patients undergo corneal refractive surgery each year in the United States. Refractive surgery includes photorefractive keratectomy (PRK) that produces intense postoperative pain. This review presents the main pain mechanisms behind PRK-related pain and the available therapeutic options for its management. Methods: Data sources included literature of cornea anatomy, treatment of PRK postoperative pain, mechanisms of corneal pain, in 3 electronic databases: Pubmed, Scopus, and Web of Science. Only double-blinded controlled trials on pain control after PRK were selected to show the endpoints, treatment, and control strategies. Results: A total of 18 double-blind, controlled trials were identified. These studies have shown the use of topical nonsteroidal antiinflammatory drugs, topical steroidal anti-inflammatory drugs, systemic analgesics, cold balanced saline solution, topical anesthetic, gabapentin, and morphine to treat postoperative pain in PRK. Discussion: The percentage of responders has seldom been reported, and few studies allow for the formal calculation of the number necessary to treat. Postoperative intense pain after PRK laser surgery remains the main challenge to its widespread use for the correction of refractive errors.