Which item is NOT typically used as a measured parameter in soft lens selection?

Which item is NOT typically used as a measured parameter in soft lens selection?

• A. Center Thickness (CT)
• B. Sagittal Height (CL-SAG)
• C. Base Curve (BC)
• D. Diameter (DIA)

Answer: (C)

In soft lens fitting, the focus is on how the lens sits on the eye and how it affects tear flow, movement, and oxygen delivery. Center thickness, diameter, and sagittal height are all physical lens attributes that the fitter considers or measures to judge fit and performance: center thickness relates to structural stability and oxygen transmission, diameter affects coverage and lid interaction, and sagittal height relates to how high the lens sits over the cornea and interacts with the tear film and lids. Base curve, on the other hand, is a design option provided by the lens manufacturer. For soft lenses, clinicians typically select from a range of base curve options rather than measuring a precise eye-based base curve with a dedicated instrument. Because the material is flexible and tolerates a bit more variation, the fit is often evaluated using trial lenses rather than a direct measurement of the eye’s BC. That’s why base curve is not typically treated as a measured parameter in soft lens selection.

In soft lens fitting, the focus is on how the lens sits on the eye and how it affects tear flow, movement, and oxygen delivery. Center thickness, diameter, and sagittal height are all physical lens attributes that the fitter considers or measures to judge fit and performance: center thickness relates to structural stability and oxygen transmission, diameter affects coverage and lid interaction, and sagittal height relates to how high the lens sits over the cornea and interacts with the tear film and lids.

Base curve, on the other hand, is a design option provided by the lens manufacturer. For soft lenses, clinicians typically select from a range of base curve options rather than measuring a precise eye-based base curve with a dedicated instrument. Because the material is flexible and tolerates a bit more variation, the fit is often evaluated using trial lenses rather than a direct measurement of the eye’s BC. That’s why base curve is not typically treated as a measured parameter in soft lens selection.