Association Between Ocular Surface Temperature and Tear Film Stability in Soft Contact Lens Wearers

PURPOSE. To investigate the correlation between the changes in the ocular surface temperature (OST) and tear film stability over soft contact lenses (SCLs). METHODS. We enrolled 20 eyes of 20 normal SCL wearers (20 men; 24.4 +/- 6 4.1 years). We used four different daily disposable SCLs: one silicone hydrogel lens (delefilcon A) and three hydrogel lenses (etafilcon A with polyvinylpyrrolidone [PVP], etafilcon A, and polymacon). OST was measured every second during 10 seconds without blinking. We defined the difference in the OST from 0 to 10 seconds as Delta OST. To evaluate tear film stability, we measured noninvasive tear break-up time (NIBUT) and tear interference patterns on the contact lenses (TIPCL) using tear film interferometry. The parameters were measured before and 15 minutes after wearing each SCL. RESULTS. Delta OST was correlated significantly with NIBUT without (r = 0.411, P < 0.01) and with SCL (r = 0.642, P < 0.01). TIPCL grade was correlated significantly with Delta OST over SCLs (r = -0.636, P < 0.01). Delta OST was significantly smaller with silicone hydrogel delefilcon A than hydrogel etafilcon A and polymacon lenses (P < 0.05 and P < 0.01, respectively). Delefilcon A and etafilcon A with PVP lenses had significantly smaller NIBUT than etafilcon A (P < 0.05 for both comparisons). TIPCL grade of delefilcon A lens was significantly smaller than those of etafilcon A and polymacon (P < 0.01 for both comparisons). CONCLUSIONS. The changes in OST over SCLs are related to tear film stability. Measurements of OST can be used to evaluate tear film stability for SCL wearers.