Functional and Emotional Impact of Dry Eye and Meibomian Gland Dysfunction in Keratoconus

Background/Objectives: Dry eye (DE) can cause persistent eye rubbing, contributing to keratoconus (KC) development and progression. Both keratoconus (KC) and dry eye (DE) significantly impact patients' functional and emotional well-being, with KC patients exhibiting a higher prevalence of DE symptoms and signs. This study examined whether functional (KEPAQ-F) and emotional (KEPAQ-E) quality of life, assessed by the Keratoconus End-Points Assessment Questionnaire, differ when influenced by symptoms and clinical signs of general DE versus meibomian gland dysfunction (MGD) in KC patients. Methods: Volunteers with KC (ages 18-70) underwent DE and MGD assessments, completing OSDI, MGD (MGDQ), and KEPAQ questionnaires. Clinical measures included NITBUT, Schirmer, and meibography. Pearson correlations and path analysis assessed relationships between DE and MGD symptoms and KEPAQ-F/E. Results: Forty-five KC participants (mean age: 45 ± 13, range: 20-69 years, 25 males) were enrolled; 22 (49%) had DE, and 15 (33%) had MGD. Significant correlations were observed between KEPAQ-E (2.9 ± 3.0 Logit) and KEPAQ-F (1.7 ± 3.0 Logit) scores with OSDI (26.5 ± 26.7) and MGDQ (3.3 ± 2.2) scores, and all Belin outcome measures A-D for all participants. In participants with diagnosed dry eye, KEPAQ E and F were also significantly correlated with loss of meibomian glands in the lower eyelids (R = -0.44, p = 0.04). Path analysis showed both DE and MGD were negatively correlated with lower KEPAQ-E and KEPAQ-F scores, with DE symptoms more influential (p < 0.05). The model explained 42% of the KEPAQ-E variance and 41% of the KEPAQ-F variance. Conclusions: Emotional and functional quality of life in KC is significantly and negatively related to DE and MGD symptoms, with DE symptoms exhibiting a greater impact. Furthermore, greater loss of meibomian glands in the lower eyelids is significantly associated with reduced emotional and functional KEPAQ scores in DE patients. These results underscore the critical importance of evaluating DE in KC to improve patient-reported outcomes.