Soft contact lenses in keratoconus.

In forming a special contact lens for use in cases of keratoconus, the centre the curves vary from 7.2 mm (47 dioptres) to 5.6 mm (60 dioptres), and at the periphery the curve is a constant 7.65 mm (44 dioptres) in all lenses. This special lens has the following advantages: (1) It protects the cornea: (2) It exerts a strong analgesic effect; (3) Vision is improved in 26% of cases from 0.03 to 0.6 and in 43% from 0.03 to 0.8. (4) Ophthalmometry gives equal values of about 69% and keratometry equal values of about 19%. The lenses may be made from PMMA, HEMA, CAB, and Polycon. The HEMA lenses did not correct the visual acuity, but those made with CAB and later with Polycon gave highly satisfactory results.