Factors affecting quality of life in keratoconus.

Abstract

To identify the factors affecting the quality of life (QoL) in adults with keratoconus, using the disease-specific Keratoconus Outcomes Research Questionnaire (KORQ). In this cross-sectional study, 574 patients with keratoconus completed the 29-item KORQ (18-item activity limitations and 11-item symptoms subscales) and demographic information. Based on mean corneal curvature to grade keratoconus severity, participants were categorised into four groups: mild <48 dioptres [D]; moderate: 48 to 53 D; advanced: 54 to 55 D and severe: >55D. Rasch analysis was used to assess the psychometric properties and to score the KORQ. Multivariable regression was performed to determine the independent impact of age, sex, laterality, severity and duration of keratoconus, education, employment status and mode of treatment for keratoconus on activity limitations and symptoms. Mean (SD) age was 24.5 (5.1) years. 304 (53%), 160 (28%), 26 (4%) and 84 (15%) belonged to keratoconus groups 1, 2, 3 and 4, respectively. Rasch analysis demonstrated the 'activity limitations' and 'symptoms' KORQ subscales to possess good psychometric properties. Statistically significant associations were found between activity limitation score and the following measures: visual acuity (VA) in the better-seeing eye (r=-0.10, p=0.01); VA in the worse-seeing eye (r=-0.09, p=0.04) and ocular aberrations (r=-0.13, p=0.008) in the worse-seeing eye. Statistically significant associations were also found between symptoms score and mean corneal curvature in the better-seeing eye (r=-0.10, p=0.02). In regression models, female sex was associated with 21% worse symptom score than male (β=-0.33, 95% CI, -0.09, -0.59, p=0.01) and working people experienced clinically and statistically significantly greater trouble from symptoms compared to those not working (β =0.44, 95% CI, 0.17, 0.70, p=0.001). People with keratoconus have poorer QoL in terms of activity limitations if they have poorer VA and greater wavefront aberrations, and in terms of symptoms if they are female and employed.