In an ideal GP lens fit, how is edge clearance typically described?

• A. Minimal
• B. Adequate
• C. Excessive
• D. None

Answer: (B)

Edge clearance refers to the space between the edge of the GP lens and the ocular surface at the periphery. In a well-fit gas-permeable lens, this clearance should be adequate—neither so tight that the edge bears on the cornea or lid margins, nor so loose that the lens becomes unstable or decentered. Adequate edge clearance allows smooth tear exchange under the edge and comfortable lid interaction while maintaining good lens centration. If the clearance is minimal, you get edge bearing and lid friction, causing discomfort and potential corneal irritation. If it’s excessive, the lens may move too much and fail to align well with the sclera/conjunctiva. Therefore, the best description for an ideal GP lens fit is adequate edge clearance.