When is the application of fluorescein best utilized?

The application of fluorescein is best utilized for assessing the fit of gas permeable lenses. When a gas permeable lens is placed on the eye, fluorescein can be instilled to visualize the tear film beneath the lens. The dye will highlight areas where the lens does not align properly with the cornea, helping practitioners evaluate the lens's central fit, edge alignment, and overall integrity of the lens-to-cornea interface.

This is especially critical since gas permeable lenses require a precise fit to ensure adequate movement and proper tear exchange. With fluorescein, a practitioner can observe patterns of staining on the cornea that may indicate areas of excessive pressure or suction caused by poor fitting. Therefore, fluorescein plays an essential role in optimizing the lens fit, ensuring both comfort and ocular health for the patient.