Too small of a lens diameter causes a lens to be which shape?

Too small of a lens diameter causes a lens to be which shape?

• A. Steep
• B. Flat
• C. Neutral
• D. Curved

Answer: (B)

When evaluating how a contact lens sits on the eye, diameter influences how much of the corneal surface the lens covers and how the edges align with the eyelids. If the lens diameter is too small, it doesn’t wrap around the cornea enough and sits on a flatter portion of the surface. This reduced wrap makes the overall fit appear flatter relative to the corneal curvature, so the lens is described as flat. A steeper fit would come from tighter engagement with the corneal contour or a larger diameter that pushes the edge in more, but with an undersized diameter the result is a flatter fit.

When evaluating how a contact lens sits on the eye, diameter influences how much of the corneal surface the lens covers and how the edges align with the eyelids. If the lens diameter is too small, it doesn’t wrap around the cornea enough and sits on a flatter portion of the surface. This reduced wrap makes the overall fit appear flatter relative to the corneal curvature, so the lens is described as flat. A steeper fit would come from tighter engagement with the corneal contour or a larger diameter that pushes the edge in more, but with an undersized diameter the result is a flatter fit.