If an alcohol-based enzyme and protein remover is used, they should not be used for more than ______ seconds.

• A. 15
• B. 60
• C. 45
• D. 30

Answer: (D)

The main idea is that alcohol-based cleaners with enzymes for protein removal must be used only for a brief, controlled contact time on gas-permeable lenses. The alcohol helps dissolve residues and the enzymes break down protein deposits, but GP lens materials can be sensitive to prolonged exposure. Extending exposure beyond a short window can dry or roughen the lens surface, affecting comfort, wettability, and integrity of the material. So, about 30 seconds provides enough time for the cleaner to work without risking damage. After the time is up, rinse thoroughly with the recommended rinse and proceed with disinfection as directed. Times longer or shorter than this balance cleaning effectiveness with lens safety, and always follow the product’s instructions.