Prospective cohort study investigating frequency and risk factors for acute pain 1 day after refractive surgery.

BACKGROUND/AIMS: To examine demographic and clinical factors associated with ocular pain 1 day after refractive surgery. METHODS: Prospective study of individuals undergoing refractive surgery. Participants rated their ocular pain on a 0-10 numerical rating scale (NRS) presurgery and 1 day after surgery. Presurgery, participants completed questionnaires on demographics, comorbidities, medications and dry eye and ocular pain symptoms; and an anaesthetised Schirmer test was performed. Acute ocular pain 1 day after surgery was defined as an NRS score of worst pain since surgery ≥3 and this group was compared with individuals with NRS scores<3. RESULTS: 251 individuals underwent refractive surgery (89% laser-assisted in situ keratomileusis, n=222; 11% PRK, n=29). Mean age was 35±8 years (range 19 to 60); 60% (n=150) self-identified as female, 80% (n=203) as White, and 36% (n=89) as Hispanic. Thirteen (5%) individuals reported ocular pain (NRS ≥3) prior to surgery and 67% (n=168) reported ocular pain 1 day after surgery (nine individuals had pain at both time points). Factors that were associated with pain 1 day after surgery included Hispanic ethnicity (adjusted relative risk (aRR) 1.42, 95% CI 1.21 to 1.68, p<0.001) and the presence of eye pain presurgery (aRR 1.10, 95% CI 1.02 to 1.18, p=0.02). CONCLUSION: A majority of individuals report moderate or greater pain within 24 hours of refractive surgery. Hispanic ethnicity and eye pain prior to surgery were associated with self-reported acute postsurgical pain.

Tear Proteins Altered in Patients with Persistent Eye Pain after Refractive Surgery: Biomarker Candidate Discovery.

Some patients develop persistent eye pain after refractive surgery, but factors that cause or sustain pain are unknown. We tested whether tear proteins of patients with pain 3 months after surgery differ from those of patients without pain. Patients undergoing refractive surgery (laser in situ keratomileusis or photorefractive keratectomy ) were recruited from 2 clinics, and tears were collected 3 months after surgery. Participants rated their eye pain using a numerical rating scale (NRS, 0-10; no pain-worst pain) at baseline, 1 day, and 3 months after surgery. Using tandem mass tag proteomic analysis, we examined tears from patients with pain [NRS ≥ 3 at 3 months (n = 16)] and patients with no pain [NRS ≤ 1 at 3 months (n = 32)] after surgery. A subset of proteins (83 of 2748 detected, 3.0%) were associated with pain 3 months after surgery. High-dimensional statistical models showed that the magnitude of differential expression was not the only important factor in classifying tear samples from pain patients. Models utilizing 3 or 4 proteins had better classification performance than single proteins and represented differences in both directions (higher or lower in pain). Thus, patterns of protein differences may serve as biomarkers of postsurgical eye pain as well as potential therapeutic targets.