Abstract:

Objective To observe the efficacy of rigid gas permeable contact lens (RGPCL) on the change of corneal morphology and diopter over time in Chinese keratoconus patients during seven-year follow up. Design Retrospective case series. Participants 62 patients (124 eyes) with clinically evident keratoconus from Tongren Eye Care Center were included. Methods All participants underwent comprehensive examinations including noncontact intraocular pressure (IOP), corneal topography, corrected visual acuity (VA), slit lamp, refraction at initial visit, which were all repeated at every visit once a year in the follow up. Main Outcome Measures Corneal curvature, refraction. Results Mean K-steep and K-flat were 52.37±5.70 D and 51.33±5.49 D, 46.56±4.68 D and 46.48±4.59 D at baseline and last visit, respectively. The changes of K-steep, K-flat and corneal astigmatism were similar, which decreased in the first three years and then increased slowly in the following years. Mean uncorrected VA, spectacle corrected VA and RGP corrected VA at first visit were LogMAR 1.18±0.46, 0.39±0.39 and 0.04±0.09 respectively and LogMAR 1.19±0.16, 0.31±0.28, and 0.04±0.06 at last visit, respectively. RGP correction maintained a good visual acuity, despite the corneal curvature fluctuated a lot during the follow up. Mean sphere and cylinder at first visit was -6.70±3.89 D and -3.63±1.71 D. At last visit, the sphere and cylinder was -8.81±3.93 D and -3.08±1.67 D, respectively. Sphere increased smoothly during the follow up period. Cylinder decreased in the first three years, then got into a plateau. Conclusion  Natural course of keratoconus could be changed by the RGP correction. Patients achieved a sustained good visual quality via a long term wearing. The change of corneal curvature was not linear but parabolic shape. (Ophthalmol CHN, 2018, 27: 358-361)

Key words: keratoconus, corneal curvature, rigid gas permeable contact lens