Question 90 of 100
(demo test)
Product Demo for COA Exam Questions
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A soft contact lens wearer soaks her lenses overnight in a disinfecting solution. She asks why she cannot put a lens straight on her eye in the morning. Which of the following must be neutralized before the lens is placed on the eye?
A hydrogen peroxide solution must be neutralized before the lens goes on the eye. Peroxide is an oxidizing disinfectant, which means it kills germs by attacking them with oxygen. It is preservative free, so it suits patients who react to preservatives in other solutions. That same strength is the problem. Raw peroxide on the eye stings and can burn the surface. After the lens soaks for the set time, the peroxide is changed into plain saline before wear. Only after that step is the solution safe for the eye.
Compare the other care products. A multipurpose solution holds everything needed to clean, disinfect, and store a lens in one bottle. Nothing is neutralized, so the lens goes on straight from the case. A rinse only washes a lens off. It does not disinfect, so it never replaces a peroxide or multipurpose system. Tap water is not a lens care product at all. Patients must never use tap water, distilled water, or homemade saline on soft or rigid lenses. Water can carry Acanthamoeba, a germ that causes a severe corneal infection. For the same reason, patients should not wear lenses in hot tubs or swimming pools. The textbook lists only two disinfecting methods for contact lenses: chemicals and ultraviolet (UV) radiation. Heat was the first method approved for soft lenses, but it is rarely used now.
Keep the sorting simple. Ask what the bottle is for. A rinse washes. A multipurpose solution cleans, kills germs, and stores. Peroxide kills germs but must be changed to saline first. Only the peroxide system has a step that must finish before the lens goes in. Teaching patients how to use each solution safely is a core part of the COA contact lens content area.
Incorrect Answers
- A. A multipurpose solution is a ready-to-wear storage fluid. It cleans, disinfects, and stores without any neutralizing step.
- C. A rinse simply washes the lens surface. It has no disinfecting power and nothing in it to neutralize.
- D. Tap water should never touch a contact lens. It is unsafe at every step, not something you neutralize and then use.
Testing Pearls
- Peroxide systems are preservative free and good for patients with solution sensitivity.
- Peroxide must be neutralized before insertion; unneutralized peroxide burns the eye.
- Multipurpose solution = clean, disinfect, and store in one bottle.
- Never use tap water, distilled water, or homemade saline; think Acanthamoeba.
- The two textbook disinfecting methods are chemicals and ultraviolet (UV) radiation.
References
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 14, Principles and Problems of Contact Lenses.
