Which statement is true regarding corneal toxicity from contact lenses?

Which statement is true regarding corneal toxicity from contact lenses?

• A. It is associated with preservatives and incomplete neutralization of H2O2
• B. It is solely due to mechanical irritation
• C. It cannot be treated
• D. It only occurs with new lenses

Answer: (A)

Corneal toxicity from contact lenses is often due to chemical factors in lens care, not just physical rubbing. Preservatives used in some lens solutions can irritate and damage the corneal epithelium, especially with prolonged exposure or when solutions are retained on the lens. In peroxide-based disinfection systems, the lens must be fully neutralized; if residual hydrogen peroxide remains, it can be toxic to the cornea, causing stinging, redness, tearing, photophobia, and epithelial disruption. Because of these chemical mechanisms, toxicity isn’t limited to new lenses, and it isn’t solely from mechanical irritation. The problem is usually reversible if the lenses are removed, the eye is rinsed, and a preservative-free or properly neutralized system is used. The other statements don’t fit because toxicity can arise from preserved solutions and incomplete neutralization, it can be treated, and it isn’t restricted to new lenses.

Corneal toxicity from contact lenses is often due to chemical factors in lens care, not just physical rubbing. Preservatives used in some lens solutions can irritate and damage the corneal epithelium, especially with prolonged exposure or when solutions are retained on the lens. In peroxide-based disinfection systems, the lens must be fully neutralized; if residual hydrogen peroxide remains, it can be toxic to the cornea, causing stinging, redness, tearing, photophobia, and epithelial disruption. Because of these chemical mechanisms, toxicity isn’t limited to new lenses, and it isn’t solely from mechanical irritation. The problem is usually reversible if the lenses are removed, the eye is rinsed, and a preservative-free or properly neutralized system is used. The other statements don’t fit because toxicity can arise from preserved solutions and incomplete neutralization, it can be treated, and it isn’t restricted to new lenses.