Evaluation of transmittance changes between different batches of contact lenses

Abstract

Aim: To evaluate the variation in transmittance in the UV-visible spectrum (230 nm 700 nm) between different batches of contact lenses (CL). Methods: Five monthly and five daily CL were studied. For each brand and power ( 3.00D), three different batches were analyzed. Transmittance (%T) was measured in the visible and ultraviolet spectral region, using a Shimadzu UV 3101 PC spectrophotometer equipped with an integrating sphere. Results: Visible Region (400–700 nm): The average values of %T for monthly lenses varied between 91.31±2.64 and 95.83±1.35. It was verified a statistically significant difference between batches (p<0.05) for all lenses. Regarding daily lenses, the average values of %T ranged between 91.90±1.63 and 96.09±3.00. A statistically significant difference between batches was also found for all lenses (p<0.001). UVA Region (315–400 nm): The average values of %T for monthly lenses varied between 20.31±32.32 and 93.58±1.89. In daily lenses, the values ranged between 18.70±30.52 and 92.32±3.43. For both types, some CL showed statistically significant differences between batches (p<0.05). UVB Region (280–315 nm): The average values of %T for monthly lenses varied between 0.02±0.07 and 91.23±1.88. For daily CL varied between 0.01±0.03 and 79.84±6.80. In this region, some CL also showed statistically significant differences between batches (p < 0.05). UVC Region (230–280 nm): The average values of %T for monthly lenses ranged between 3.29±0.07 and 53.69±35.65. For daily CL varied between 1.35±12.06 and 40.09±23.70. In this region, no statistically significant differences between batches were observed. Conclusion: There are changes in transmittance values between different batches, more pronounced in some regions of UV-Visible spectrum. In the visible region, all lenses differ significantly in their transmittance, but the differences obtained may have no impact on visual performance.