Why isn't a higher concentration of disinfectant used to clean contact lenses?

 A higher concentration of disinfectant should not be used to clean contact lenses due to several reasons that relate to the delicate balance between efficacy and safety:

1. **Tissue Irritation:** Contact lenses sit directly on the eye's surface, which is a very sensitive tissue. A higher disinfectant concentration could potentially cause irritation, discomfort, or even damage to the eyes, leading to conditions such as conjunctivitis or corneal ulcers.

2. **Contact Lens Damage:** Many disinfectants can damage the structural integrity of contact lenses, especially if used at higher concentrations. This can alter their fit, reduce their clarity, and make them more permeable to potentially harmful agents.

3. **Chemical Residue:** A higher concentration of disinfectant may leave behind more residue on the contact lenses after rinsing. Even trace amounts of disinfectant residue can cause discomfort and may be toxic to the eye.

4. **Sensitivity and Allergies:** Some people have sensitive eyes or allergies to certain chemicals. Using a higher concentration of disinfectants can exacerbate these issues, causing more harm than good.

5. **Antimicrobial Efficacy:** Disinfectants are tested and formulated to be effective at certain concentrations. Beyond the optimal concentration, there may be no additional benefit in terms of antimicrobial action, but increased risks of adverse effects.

It's important for contact lens solutions to be effective against bacteria, fungi, and viruses to prevent eye infections, but they also must be safe and suitable for daily use without damaging the lenses or harming the eye.