To compare the amount of protein deposits adhering to human-worn soft contact lenses, using the untreated contact lens from the contralateral eye as controls, to investigate the capabilities of the No Rub contact lens cleaning systems in protein removal from soft contact lenses.
New 1 Day Acuvue soft contact lenses were worn on a daily-wear basis by 16 Hong Kong Chinese volunteers on 5 separate days. Four right lenses of each subject were treated with No Rub contact lens cleaning systems (Alcon Opti-Free Express, Alcon Opti-Free Express No Rub Lasting Comfort Formula, B&L ReNu MultiPlus, and Ciba Vision SOLO Care Plus). The total amount of protein was extracted from all contact lenses and analyzed by the Bradford assay.
Among the contralateral contact lenses, there was no significant difference in the total protein extracted (TPE; 11.2 ± 3.8 vs. 12.6 ± 5.2 mg/ml, p = 0.20). There was a significant positive correlation in TPE between two lenses worn by the same volunteer (R2 = 0.84, y = 0.79 x + 1.3, p < 0.001). Lenses treated with Opti-Free Express and Opti-Free Express No Rub Lasting Comfort Formula solutions had significantly less TPE (7.3 ± 5.2 and 6.7 ± 4.1 mg/ml, respectively, p < 0.001) than the untreated contralateral lenses (12.7 ± 6.8 and 13.2 ± 5.3 mg/ml, respectively). No statistical difference in TPE was detected in the lenses treated with ReNu MultiPlus (13.0 ± 7.8 mg/ml, p = 0.49) and Solo Care Plus (12.1 ± 8.7 mg/ml, p = 0.99) solutions when compared with their untreated contralateral lenses (13.0 ± 7.8 and 12.1 ± 8.7 mg/ml, respectively).
Not all no-rub contact lens solutions were shown capable of removing the protein deposit from soft contact lenses.