What is the normal soft lens diameter range?

• A. 12.0 to 14.0 mm
• B. 14.5 to 16.5 mm
• C. 13.5 to 15.5 mm
• D. 15.0 to 17.0 mm

Answer: (C)

Diameter is the horizontal size of a soft contact lens, and getting it right helps the lens sit centered on the eye without rubbing the lids. For soft lenses worn in daily practice, the normal range is about 13.5 to 15.5 millimeters. This size range provides enough corneal coverage for good centration while staying comfortable with natural eyelid movements. If the diameter is smaller than this, the lens can decenter, lift at the edges, or feel unstable. If the diameter is larger, it can press on the scleral conjunctiva or feel bulky and uncomfortable, also reducing stability. Therefore, the 13.5 to 15.5 mm range best fits what clinicians consider a typical, well-fitting soft lens diameter.