Impression ring is associated with which fitting characteristic?

Impression ring is associated with which fitting characteristic?

• A. Loose fitting lens
• B. Tight fitting lens
• C. Extended wear with low modulus
• D. Daily wear with high modulus

Answer: (B)

An impression ring shows that the lens is fitting too tightly. When the edge of the contact lens presses firmly against the cornea, it compresses the corneal epithelium and displaces the tear film around the lens edge. This creates a circular indentation that can be seen as a distinct ring on the corneal surface after the lens is removed. It reflects limited lens movement and poor tear exchange caused by a tight fit. This isn’t primarily about how stiff the lens is or whether it’s worn daily or for extended periods. Those factors influence comfort and oxygen supply, but the impression ring specifically signals excessive edge pressure from a too-tight fit.

An impression ring shows that the lens is fitting too tightly. When the edge of the contact lens presses firmly against the cornea, it compresses the corneal epithelium and displaces the tear film around the lens edge. This creates a circular indentation that can be seen as a distinct ring on the corneal surface after the lens is removed. It reflects limited lens movement and poor tear exchange caused by a tight fit.

This isn’t primarily about how stiff the lens is or whether it’s worn daily or for extended periods. Those factors influence comfort and oxygen supply, but the impression ring specifically signals excessive edge pressure from a too-tight fit.