건성안에서 일회용 토릭소프트렌즈의 초과 착용으로 유발되는렌즈의 축 틀어짐, 자각 증상 및 시력 변화

Purpose: This study investigated the changes in subjective discomfort, visual acuity, lens centration, and axis destabilization among subjects who wear daily disposable toric soft contact lenses (toric lenses), for longer than the recommended duration. Methods: Two daily disposable toric lenses with different axial stabilization designs and material properties (nelfilcon A=Lens A, somofilcon A=Lens B) were fitted to subjects with dry eye symptoms and less than 10 seconds of non-invasive break-up time (NIBUT). The subjective symptom score, visual acuity, lens centration, and axis rotation were measured immediately after insertion of the lenses, and when the lenses caused increased subjective discomfort.
Results: Subjective discomfort was increased due to both disposable toric lenses because of overuse. Subjective discomfort scores were the highest for tiredness and dryness. Visual acuity was greater than 0.02±0.05 logMAR immediately after wearing both lenses. However, it decreased to 0.09 for Lens A and 0.07 for Lens B after overuse. The difference was statistically significant. For both lenses, lens centration tended to move to the center of the pupil with overuse. The axis was rotated by 5° immediately after wearing in both lenses. However, the axis was tilted by 12° and 8°, in Lens A and B, respectively, after overuse. Axis rotation larger than 10° was observed for 8 (33.3%) Lens A and 3 (13%) for Lens B. Measurement differences between immediately after insertion and after overuse were statistically significant. Conclusions: This study confirmed that overuse of daily disposable toric lenses not only causes subjective discomfort, but also changes the axis rotation and decreased visual acuity. Therefore, it is suggested that sufficient education is required to know the complications caused by overuse of toric lenses.