Which lens feature is most likely to cause an impression ring?

Which lens feature is most likely to cause an impression ring?

• A. Loose fitting lens
• B. High modulus extended wear
• C. Tight fitting lens
• D. Soft daily wear lens

Answer: (C)

A tight lens edge pressing against the cornea is most likely to produce an impression ring. When the fit is too snug, the edge indents the peripheral cornea and alters the tear film in that zone, creating a circular imprint around the central cornea that can be visible with fluorescein. This imprint reflects mechanical indentation from the lens edge rather than mere movement or material properties. A loose-fitting lens tends to move a lot and may cause lid-induced issues rather than a stable ring pattern. A high modulus extended wear lens is stiffer and more prone to rubbing, but doesn’t inherently create this distinct corneal imprint. Soft daily wear lenses are designed to conform fairly well to the cornea and are less likely to form such an imprint. If you see an impression ring, the lens fit should be reassessed and likely re-fitted to a looser edge or different diameter/base curve to relieve the pressure and prevent corneal indentation.

A tight lens edge pressing against the cornea is most likely to produce an impression ring. When the fit is too snug, the edge indents the peripheral cornea and alters the tear film in that zone, creating a circular imprint around the central cornea that can be visible with fluorescein. This imprint reflects mechanical indentation from the lens edge rather than mere movement or material properties.

A loose-fitting lens tends to move a lot and may cause lid-induced issues rather than a stable ring pattern. A high modulus extended wear lens is stiffer and more prone to rubbing, but doesn’t inherently create this distinct corneal imprint. Soft daily wear lenses are designed to conform fairly well to the cornea and are less likely to form such an imprint.

If you see an impression ring, the lens fit should be reassessed and likely re-fitted to a looser edge or different diameter/base curve to relieve the pressure and prevent corneal indentation.