To determine whether tear osmolarity contributes to the assessment of the ocular surface in soft contact lens (CL) wearers.Methods:
Prospective, case–control series in 44 CL wearers (28 tolerant and 16 intolerant) and 34 healthy subjects. Every patient underwent a thorough ophthalmic examination with a tear osmolarity test (TearLab System), conjunctival impression cytology and meibomian lipid sampling. Symptoms, break-up time (BUT), tear osmolarity, conjunctival expression of HLA-DR and meibomian fatty acid composition were evaluated.Results:
Tear osmolarity did not differ between controls and CL wearers (p=0.23). Flow cytometry results expressed in antibody-binding capacity (ABC) units and percentage of positive cells revealed a significant difference between the intolerant CL wearer group and the control group (p<0.0001). Comparisons between tolerant and intolerant CL wearers showed only a significant difference for mean fluorescence levels expressed in ABC units (p<0.0001). The BUT was significantly shorter in intolerant and tolerant CL wearers subjects than in healthy subjects (p<0.0001), whereas there was no significant difference in meibomian fatty acid composition (p=0.99) between the two groups.Conclusion:
Contact lens wear is responsible for ocular surface alterations whose patterns are very similar to those reported in early dry-eye syndrome. However, tear osmolarity was not modified in these selected CL wearers. The yield of tear osmolarity with TearLab™ in assessing ocular surface disorders in CL wearers deserves further investigation.