For a patient with the given data, what diameter should be chosen?

• A. 8.5mm-9.0mm
• B. 9.5mm-9.7mm
• C. 10.0mm-10.5mm
• D. 9.0mm-9.2mm

Answer: (B)

The key idea is matching the lens diameter to the corneal and eyelid anatomy so the GP lens sits centered with proper edge lift and tear exchange. In this patient, measurements indicate an average corneal size and typical scleral contour, so a standard corneal GP diameter around 9.5 to 9.7 mm provides the best balance: it covers the cornea adequately to maintain stable centration while staying within the white of the sclera so the edges don’t ride onto the conjunctiva or catch the lids.

Choosing a smaller diameter, like 8.5–9.0 mm, risks the lens riding up and decentering, with insufficient tear exchange under the edge. A larger diameter, such as 10.0–10.5 mm, increases the chance of edge contact with the sclera or lids, leading to discomfort and poorer alignment. Thus, 9.5–9.7 mm best fits the data by offering good corneal coverage, stable centration, and comfortable edge behavior.