Purpose: To introduce a practical method based on the topographic values for rigid gas-permeable contact lens (RGPCL) fitting in keratoconus patients. Methods: Thirty-three eyes of 17 consecutive patients with keratoconus were studied between July 1997 and April 1999. The initial ophthalmologic examination consisted of visual acuity examination, refraction, biomicroscopy, corneal topography with Eye Sys system. The tested contact lenses were selected based on results of corneal topography 1.5 mm superiorly from the visual axis at 90º the base curve. Results: Rigid gas-permeable contact lens fitting was successful in 30 eyes (91%). There was improvement in visual acuity in all eyes, ranging from 20/20 to 20/60. A mean of 3 ±1 tests were performed to select the final contact lenses parameters. Refitting was necessary in 3 cases (10%). The majority of the rigid gas-permeable contact lenses (57%) had their base curves similar to K 1.5 mm superiorly from the visual axis compared to K value. This finding was confirmed with statistical analysis of the individual measurements and the mean differences between the two topographic measurements and the final base curve of the lens. Conclusions: Rigid gas-permeable contact lens fitting based on the corneal topography 1.5 mm superior from the visual axis at 90º showed to be easy and efficient for eyes with keratoconus.
Keratoconus; Contact lenses; Corneal topography; Astigmatism; Ocular adaptation
