Abstract
Purpose :
Previous study have demonstrated the antimicrobial activity of melimine contact lenses was retained for three nights of wear but began to lose activity after six nights of wear, and was lost after 14 days of wear. This loss of activity may be due to fouling of the lens surface by tear film components. Aim of this pilot study was to determine the total protein (TP) deposited on the antimicrobial contact lenses after three nights and two weeks of extended wear.
Methods :
Contact lenses worn for 14 days from 10 randomly selected subjects who were enrolled in the melimine antimicrobial contact lens (MACL) clinical trial were collected. The study received ethics approval (LEC 05-15-057) and was registered with the Clinical Trial Registry of India (CTRI/2015/10/006327). Lenses were also collected from five subjects who wore MACL and control lenses for just three nights (ethics approval LEC 07-17-066; Clinical Trial Registry of India: CTRI/2017/09/015296). Both studies were prospective, randomised, double-masked, contralateral human clinical trials conducted at L V Prasad Eye Institute, Hyderabad, India. Contact lenses from both eyes of the subjects were aseptically collected. The TP deposited on the lens was extracted using 1.5 ml of acetonitrile:0.2% trifluoroacetic acid (50:50) for 24 hours at 37°C incubation. The amount of TP was determined by the bicinchoninic acid assay. The comparison of TP deposition between the antimicrobial and control lenses was analysed using the Wilcoxon Signed Rank Test.
Results :
The TP recovered from the three-day worn antimicrobial contact lens was 8.73 ± 1.04 mg/mL whereas 9.12 ± 0.52 mg/mL was recovered from the control lenses. The TP recovered from the 14-day worn antimicrobial contact lens was 10.06 ± 2.56 mg/mL whereas 10.64 ± 2.76 mg/mL was recovered from the 14-day worn control lenses. There was no significant difference in the TP deposition between antimicrobial and control lenses after three days or two weeks of extended wear (p ≥ 0.25). There was no difference in the amount of protein extracted after three or 14 days of wear.
Conclusions :
In our previous study the antimicrobial activity of MACL was retained after three days of wear, but was lost after 14 days of wear. The current study suggests that protein deposition on lenses was not the reason for this loss of activity as the amount of TP adsorbed to lenses was equivalent between three and 14 days.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.