Rose K lenses for keratoconus--an Indian experience

To describe initial lens selection and our experience of Rose K lens fitting in keratoconus in Indian eyes.

Retrospective study of patients who underwent the Rose K contact lens (CL) trial during a 6-month period from July 2007 to December 2007 in a tertiary eye care centre in South India. We obtained data on patient demographics, prefitting refraction and best spectacle-corrected visual acuity, corneal topography data whenever available, number of trials performed, CL parameters, and vision with final CL. The base curve (BC) of the CL and the topographic indices were analyzed to find the correlation. If the coefficient of correlation was significant, the relationship was further examined using multiple regression analysis. A "P" value of <0.05 was considered statistically significant.

One hundred twenty-eight eyes of 80 patients who underwent the Rose K trial were included in the study. The group included 50 male patients and the mean age was 21.92 +/- 7.14 years. The mean spherical refractive power was -6.11 +/- 5.76 diopter (range: 0 to -20.00 diopter) and mean cylinder was -4.29 +/- 3.46 diopter (range: 0 to -22). The mean number of CL trial performed was 1.73 +/- 0.9 (range: 1-5). All patients were fitted with the standard Rose K lens with diameter 8.7 mm. The mean BC of the lens was 6.3 +/- 6.02 mm, and the mean power was -11.4 +/- 5.78. The 5-mm average K was the best predictor of the BC of the Rose K lens in all grades of keratoconus.

Selecting the BC of the initial trial lens based on the 5-mm average K on the axial map can reduce the complexity and chair time in fitting Rose K lenses in keratoconic eyes.