Attendance for the investigation and evaluation of a patient for the fitting of contact lenses, with keratometry and testing with trial lenses and the issue of a prescription-one service in any period of 36 months-patient with irregular astigmatism in either eye, being a condition the existence of which has been confirmed by keratometric observation, if the maximum visual acuity obtainable with spectacle correction is worse than 0.3 logMAR (6/12) and if that corrected acuity would be improved by an additional 0.1 logMAR by the use of a contact lens