What effect does decreasing the optical zone of a GP lens have?

Decreasing the optical zone of a GP (gas permeable) lens primarily affects the clearance between the lens and the cornea, which can lead to an increased tear exchange. When the optical zone is made smaller, there is usually more area for the tears to flow under the lens, allowing for a better exchange of tears. This can help in maintaining a healthy ocular surface, as fresh tears replace the old ones, providing nutrients and removing debris.

This is particularly important in GP lenses, as maintaining moisture and health of the cornea is crucial for comfort and visual clarity. The enhanced tear exchange can also help in managing lens deposition and maintaining a stable tear film, which is essential for optimal vision.

While comfort, optical clarity, and lens thickness can be affected by changes in the optical zone, these are not the main effects linked specifically to a decrease in the optical zone. Therefore, the focus should be on the direct relationship between a smaller optical zone and increased tear exchange efficiency, which highlights its importance in lens fitting and eye health.