AIM:To investigate the effect of the Hiline rigid gas permeable contact lens(Hiline RGPCL)for keratoconus in clinical practice and the predictors for RGPCL fitting.

METHODS:Fifty-seven eyes in 36 patients with keratoconus fitted with Hiline RGPCL were divided into three groups, mild(n=10), moderate(n=24)and advanced(n=23)group. After fitting evaluation, visual acuity measurements were taken to compare the best corrected visual acuity wearing spectacle lenses and Hiline RGPCL. The predictors for RGPCL fitting by the corneal curvature were analyzed.

RESULTS:In all groups, the application of Hiline RGPCL obtained acceptable vision. There was statistically significant improvement in vision with the Hiline RGPCL than that of with spectacle lenses in mild group(t=-2.968,P=0.016), moderate group(t=-6.293,P<0.01)and advanced group(t=-12.792,P<0.01). The mean base curve of the lens was 6.8±0.75mm. The base curve of RGPCL correlated with corneal curvature. In mild group, the base curve of RGPCL correlated with Sim K steep(r=0.715,P=0.02). In moderate group, the base curve of RGPCL correlated with average K as well as 0.2mm steeper average K(r=0.495,P=0.014). In advanced group, the base curve of RGPCL correlated with every indicator, especially the corneal curvature in central area(r=0.802,P<0.01).

CONCLUSION:Guiding by corneal topography, improvement of visual acuity is successfully achieved by fitting with Hiline RGPCL. Selecting different predictors in different grades can reduce the complexity and improve the usefulness of the Hiline RGPCL in clinical practice.