Assessment of meibomian glands and tear film in post-refractive surgery patients

Importance: Corneal refractive surgery may impact meibomian gland and tear film in post-refractive surgery patients. Background: To compare ocular surface parameters between post-refractive surgery patients and normal controls. Design: Cross-sectional single centre study. Participants: A total of 120 eyes of 120 subjects were divided into three groups: (i) 60 controls and 60 patients underwent corneal refractive surgery at least 12 months ago; (ii) 30 post-laser in-situ keratomileusis (LASIK) patients and (iii) 30 post-laser epithelial keratomileusis (LASEK)/photo-refractive keratectomy (PRK) patients. Methods: Tear meniscus height, non-invasive keratographic tear film break-up time and meibography were measured using the Keratograph^® 5M. Fluorescein break-up time, ocular surface staining, examination of lid margins and meibomian glands, Schirmer's test and Ocular Surface Disease Index questionnaire were performed. Main Outcome Measures: Ordinary logistic regression was performed to evaluate the impact of clinical variables including refractive surgery on the meiboscores. Results: In post-LASIK patients, ocular surface parameters including Ocular Surface Disease Index scores, fluorescein break-up time and staining scores, except Schirmer's scores, were significantly worse than those in controls (P < 0.050). Ocular surface staining scores in post-LASEK/PRK patients was higher than that in the controls (P = 0.001). In post-refractive surgery patients, grade of meibomian gland parameters and meiboscores were worse than those of controls (all P < 0.050). Histories of refractive surgery were associated with high meiboscore (β = 1.100, P = 0.043 for LASIK and β = 1.039, P = 0.042 for LASEK/PRK). Conclusions and relevance: Corneal refractive surgery may adversely affect the ocular surface, and a reduction of functional meibomian glands can contribute to chronic tear film dysfunction after corneal refractive surgery.