Characteristics and survey of keratoconic contact lens wearers who are lost to follow up

BackgroundKeratoconic patients often require contact lenses for visual correction; a significant number discontinue clinic attendance and are lost to follow up'. This study identifies the characteristics of patients who discontinued or continued attendance and investigates ongoing visual management. MethodsRecords were retrieved for 102 patients lost to follow up from the contact lens clinic for three or more years (cases). They were matched to 102 contemporaneous patients who continued attendance (controls). Parameters were compared to identify differences between the groups using logistic regression. Parameters investigated were gender, age, distance from home to clinic, duration of keratoconus, duration of clinic attendance, unilateral or bilateral diagnosis, whether one eye had received a graft, back optic zone radius (BOZR) and wear time. A survey investigated how discontinued cases were managing and the reasons for discontinuation such as comfort and handling problems. ResultsThere were no significant differences between cases and controls for gender, age, distance from home or having received a graft. Odds of discontinuation in unilateral patients were 2.6 times that of bilateral patients (p = 0.003). Fifty-three per cent of unilateral and 41 per cent of bilateral patients who discontinued did so within one year. Cases had shorter median duration since diagnosis (3.0 years versus 11.0 years, p < 0.0001) and shorter wearing times (56 hours per week versus 84 hours per week, p < 0.0001). BOZR was not significantly different between the two groups. The survey revealed poor comfort, handling problems and the ability to manage without as most common reasons cited. ConclusionBOZR, an indicator of disease severity, was not associated with non-attendance. In general neophytes and those wearing a lens in one eye were more likely to discontinue.