Role of the Water Gradient Structure in Inhibiting Thin Aqueous Layer Break in Silicone Hydrogel-Soft Contact Lens

PURPOSE: Soft contact lenses (SCLs) are effective for refractive error correction, but prolonged wear triggers discomfort and discontinuation. This study investigates whether water gradient technology of delefilcon A-based SCLs improve tear film dynamics. METHODS: This retrospective observational study included 50 asymptomatic delefilcon A or narafilcon A users. Data on thin aqueous layer break (TALB; %), noninvasive tear break-up time (NIBUT), tear meniscus height (TMH; mm), subjective dryness, and higher-order aberrations (HOAs) were collected. Measurements of the bare eye, the SCL-worn eye after 15 minutes (visit 1 [v1]) and 30 ± 5 days after v1 after SCL was worn for ≥5 hours (visit 2 [v2]) were recorded. RESULTS: TALB was significantly reduced in the delefilcon A group compared to the narafilcon A group (33.3% vs. 85.5% at v1; P < 0.0001 and 31.7% vs. 80.4% at v2; P < 0.0001). The NIBUT was also significantly higher in the former (4.2 ± 2.1 seconds vs. 2.9 ± 1.5 at v1; P < 0.01 and 4.1 ± 2.3 seconds vs. 2.7 ± 1.6 seconds at v2; P < 0.01) across both visits. The TMH was significantly reduced in the former in both v1 and v2. The total ocular HOAs were significantly lower in the former at v1 (P < 0.001) and v2 (P < 0.05) compared to the bare eye. CONCLUSIONS: The water gradient technology of delefilcon A reduces TALB and increases NIBUT. TRANSLATIONAL RELEVANCE: The use of water gradient technology improves tear film dynamics and alleviate pathological break-up pattern, improving lens performance.