[Radial keratotomy: analysis of undercorrected patients, based on 200 successive operations]

The authors present the results of a series of 200 radial keratotomies. there were two anatomical complications, neither of which caused any clinical damage. 83% of patients obtained 5/10 distant visual acuity or more without correction. The overcorrection rate was 1.5%. The incidence of induced astigmatism was 3.0%. The real failure of the method lay in an undercorrection rate of 13%. These cases are analysed here. Correction proved easier as patients were older: 0.64 diopters per decade. There was a 0.30 diopter gain in men over women. With corneal curvature of more than 43.5 diopters, the benefit was 0.15 diopters per diopter of keratotomy. Limbus to optical zone incisions provided 1.60 diopters as compared with optical zone to limbus incisions, while redeepening incisions provided only 0.27 diopters. Emphasis is placed upon practical matters, such as quality of measurement, instruments and the dexterity of the surgeon. We limit surgical indications to within the range of -1.50 diopters to -4.50 diopters of myopia. The undercorrection rate within this myopia range was 6.3%, increasing to 39.0% over the range.