Certified Ophthalmic Technician (COT) Practice Test

The recommended method for cleaning dirty lenses on a refractor/phoropter is to use a lint-free swab lightly moistened with either alcohol or ether. This method is effective because the lint-free swab minimizes the risk of scratching the lens surface while providing a controlled application of the cleaning agent. Alcohol or ether is suitable for dissolving oils, fingerprints, and other debris without damaging the lens coatings, ensuring that the optical clarity is maintained. In contrast, using a dry cloth may lead to particles scratching the lens if the cloth is not clean, and it does not effectively remove oils or smudges. Tap water could potentially leave mineral deposits or streaks on the lenses, and using a cloth alongside water might not be effective for thorough cleaning. Compressed air, while useful for removing dust or loose particles, does not clean smudges or oils and could potentially blow contaminants further onto the lens. Thus, the use of a lint-free swab with an appropriate solvent is the optimal choice for maintaining the integrity and performance of refractor/phoropter lenses.