Depression and acute and pre-existing pain was found in 11% of those who experienced ocular pain after refractive surgery. Photo: Martin L. Fox, MD. Click image to enlarge.

Ocular pain has been shown to be a potential side effect of refractive surgery, but no studies have examined the frequency and risk factors. Researchers recently examined ocular pain after LASIK and photorefractive keratectomy (PRK) and found that ocular pain pre-surgery, depression pre-surgery, use of an oral anti-allergy medication and pain intensity day one post-surgery were risk factors.

A total of 109 individuals ranging in age from 23 to 57 underwent refractive surgery (87% LASIK, 13% PRK) and were followed for six months after. Participants rated their ocular pain on a zero to 10 numerical rating scale (NRS) pre-surgery and one day, three months and six months post-surgery. A clinical exam focused on ocular surface health was performed three and six months post-surgery, with persistent ocular pain defined as an NRS score ≥3. This group was compared with a control group with NRS scores <3 at both timepoints.

Eight (7%) individuals reported ocular pain prior to surgery, with the frequency of ocular pain increasing after surgery to 23% (n=25) at three months and 24% (n=26) at six months. Twelve individuals (11%) reported an NRS ≥3 at both timepoints and comprised the persistent postoperative pain (PPOP) group. The pain was not related to visual acuity or ocular surface signs of disease (e.g., tear production, stability), suggesting that neuropathic mechanisms may play a role.

“Topical anesthesia eliminated pain in 10 of 12 individuals, further suggesting peripheral mechanisms at the three- and six-month timepoints in the majority of individuals,” the authors wrote in their paper.

The 11% of patients that made up the PPOP group is within the range reported for PPOP after other surgeries, including dental implants, inguinal hernia repair, thoracotomy and breast surgery.

“Furthermore, some risk factors identified in our study for persistent ocular pain are shared with those from prior PPOP studies, including pre-existing pain, acute pain and depression,” the authors explained.

They found that use of oral anti-allergy medication pre-surgery was associated with PPOP after surgery as well. “Interestingly, a similar finding was noted in a prior study where oral antihistamine use predicted PPOP using a dry eye-specific questionnaire six months after cataract surgery,” they noted.