HIGH ASTIGMATISMEvaluation
Jessica Conroy OD, FAAO
Evaluation of a toric GP lens should be same as with a spherical GP on a spherical cornea1
-
- Utilize sodium fluorescein (NaFl) and cobalt blue filter to evaluate the lens-to-cornea fitting relationship2
- Descriptions2
-
- Areas where NaFl is present in the tear layer appear to be GREEN
- Areas where NaFl is absent (or is too thin to detect) appear BLACK
-
- Alignment Fit: observed when lens evenly contours cornea2
-
- Center: light, even tear pooling
- Mid-Periphery: thin, even, circular band of bearing
- Edge: even tear clearance to allow for sufficient tear exchange
-
Sources
- Bennett ES, Henry VA, Kinoshita BT, Lampa M. Correction of Astigmatism. In Bennett ES, Henry VA. Clinical Manual of Contact Lenses, 5th ed., Wolters Kluwer, Philadelphia, PA, 2020:388–439.
- Bennett ES, Sorbara L, Kojima R. Gas Permeable Lens Design, Fitting, and Evaluation. In Bennett ES, Henry VA. Clinical Manual of Contact Lenses, 5th ed. Wolters Kluwer, Philadelphia, PA, 2020:134–185.