Clinical Tests for Successful Contact Lens Wear: Relationship and Predictive Potential

Abstract

Although comfort is important for contact lens wearers, common clinical tests can fail to predict patients' symptoms. Lid wiper epitheliopathy (LWE) and lid parallel conjunctival folds (LIPCOF) are related to dry eye symptoms in lens wearers. This study investigates the predictive value of LWE and LIPCOF as objective measures of discomfort, and their relation to the ocular surface in soft contact lens wearers. Subjects were classified as symptomatic or asymptomatic, using the Contact Lens Dry Eye Questionnaire (CLDEQ). Pre-lens tear break-up time (PLBUT), limbal and bulbar hyperaemia, corneal staining, LWE and LIPCOF were assessed in the right eyes of 61 (23 M, 38 F; mean age 32.1 years; range = 18 to 55) experienced contact lens wearers. Differences between groups, and relationships between LWE, LIPCOF (nasal, temporal and sum) and objective signs were examined using non-parametric analyses. The positive and negative predictive values for symptoms of each objective measure were calculated. Thirty eight subjects were classified as asymptomatic, 23 symptomatic. LWE and LIPCOF severity scores were significantly increased in symptomatic patients (U-test, p < 0.03), while no significant differences were found between groups for PLBUT, corneal staining or hyperaemia (0.29 < p < 0.88). Significant positive correlations were found between LWE and LIPCOF scores (temporal r = 0.67, p < 0.001; nasal r = 0.39, p < 0.001), and between LWE and hyperaemia (bulbar, r = 0.28, p < 0.001; limbal r = 0.36, p < 0.001). Age and gender were different in the two groups (p < 0.05). The predictive value of temporal LIPCOF was positive = 56.9%, negative = 77.1% with a cutoff value of > or =2 (PPV/NPV/cutoff value), of nasal LIPCOF 70.7%/75.0%/> or =1, of LIPCOF Sum 79.8%/86.5%/> or =2, and of LWE 53.1%/81.1%/> or =1. Contact lens wearers with dryness symptoms exhibit significantly more LWE and LIPCOF, but not increased corneal staining, bulbar hyperaemia or decreased PLBUT. LWE and LIPCOF are significantly correlated: this may reflect their common frictional origin. LIPCOF Sum severity scores appear to be most predictive for symptoms.