Ocular Pain after Refractive Surgery: Interim Analysis of Frequency and Risk Factors

Abstract

Purpose: To examine the frequency and risk factors for ocular pain after laser assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).

Design: Prospective study of individuals undergoing refractive surgery at 2 different centers.

Participants: One hundred nine individuals undergoing refractive surgery: 87% LASIK and 13% PRK.

Methods: Participants rated ocular pain on a numerical rating scale (NRS) of 0 to 10 before surgery and 1 day, 3 months, and 6 months after surgery. A clinical examination focused on ocular surface health was performed 3 and 6 months after surgery. Persistent ocular pain was defined as an NRS score of 3 or more at both 3 and 6 months after surgery (patients), and this group was compared with individuals with NRS scores of < 3 at both time points (control participants).

Main outcome measures: Individuals with persistent ocular pain after refractive surgery.

Results: The 109 patients who underwent refractive surgery were followed up for 6 months after surgery. Mean age was 34 ± 8 years (range, 23-57 years); 62% self-identified as female, 81% as White, and 33% as Hispanic. Eight patients (7%) reported ocular pain (NRS score ≥ 3) before surgery, with the frequency of ocular pain increasing after surgery to 23% (n = 25) at 3 months and 24% (n = 26) at 6 months. Twelve patients (11%) reported an NRS score of 3 or more at both time points and constituted the persistent pain group. Factors that predicted persistent pain after surgery in a multivariable analysis were (1) ocular pain before surgery predicated persistent pain after surgery (odds ratio [OR], 1.87; 95% confidence interval [CI], 1.06-3.31), (2) symptom report of depression before surgery (Patient Health Questionnaire-9: OR, 1.3; 95% CI, 1.1-1.6; P = 0.01), (3) use of an oral antiallergy medication before surgery (OR, 13.6; 95% CI, 2.1-89.3; P = 0.007), and (4) pain intensity day 1 after surgery (OR, 1.6; 95% CI, 1.2-2.2; P = 0.005). There were no significant associations between ocular surface signs of tear dysfunction and ocular pain, P > 0.05 for all ocular surface signs. Most individuals (> 90%) were completely or somewhat satisfied with their vision at 3 and 6 months.

Conclusions: Eleven percent of individuals reported persistent ocular pain after refractive surgery, with several preoperative and perioperative factors predicting pain after surgery.

Financial disclosure(s): Proprietary or commercial disclosure may be found after the references.

Keywords: Epidemiology; Ocular pain; Persistent pain; Refractive surgery; Risk factors.

Figure 1:

Study timepoints and assessments.

Figure 2:. Ocular pain score frequencies at the pre- and post-surgery timepoints demonstrating an overall increase in pain scores at the 3- and 6-month visits compared to pre-surgery.

Numerical Rating Scale (NRS). A) Pre-surgery; B) Day 1 Post-surgery; C) Month 3 Post-surgery; D) Month 6 Post-surgery

Figure 3:. Individual pain intensity ratings demonstrate heterogeneity with regards to pain intensity pre-surgery and day 1 post-surgery in all three groups.

(A) 68 individuals without persistent pain (controls: NRS<3 at both 3 and 6 months); (B) 12 individuals with persistent pain (cases: NRS≥3 at 3 and 6 months); and (C) 27 individuals with pain at one, but not both, time points (3 or 6 months). Each individual line is shown in an arbitrary color to allow visual tracking of each individual over time.