Diurnal Variation in Comfort in Contact Lens and Non‐contact Lens Wearers

PURPOSE: The purpose of this investigation was to evaluate the diurnal variation in symptoms associated with ocular discomfort in contact lens (CL) wearers and non-CL wearers. METHODS: The study population comprised 604 individuals attending pre-screening visits at the OTG-i research clinic; 60% were current soft CL wearers (hydrogel and silicone hydrogel) and 40% were non-CL wearers. Symptomatology status was determined by the OSDI questionnaire (58% asymptomatic, 42% symptomatic). Participants were asked to grade their comfort, vision, and other symptoms during the day and in the evening (before lens removal for CL wearers) on 0 to 100 visual analogue scales. RESULTS: Diurnal decrease in comfort was significantly greater for CL wearers (-16.0 vs. -6.3, p < 0.001) and symptomatic participants (p = 0.015). Diurnal decrease in subjective vision was also significantly greater for CL wearers (-10.4 vs. -6.9, p = 0.005) and symptomatic participants (p = 0.001), and the interaction between these factors was also significant (p = 0.019). Dryness, grittiness, and irritation increased significantly more for CL wearers (p < 0.001, p = 0.012, and p = 0.004, respectively) and grittiness, irritation, and stinging for symptomatic participants (p = 0.016, p < 0.001, and p < 0.001, respectively). For the CL wearers, there was a significant interaction between dryness and age (p = 0.026) with the diurnal increase in dryness being greater in those under 40 (+15.6 vs. +10.0). CONCLUSIONS: The diurnal decrease in comfort and subjective vision, and the diurnal increase in dryness, grittiness, and irritation, were significantly more marked for CL wearers than non-CL wearers. Diurnal changes in comfort, grittiness, stinging, irritation, and vision were influenced by the subject's overall symptomatology as assessed by the OSDI questionnaire. For dryness symptoms, the diurnal decrease was most marked in young CL wearers. For the symptoms of stinging and vision, the diurnal changes were most pronounced in the symptomatic groups.