Five-year results of radial keratotomy

We present 5-year findings on 198 consecutive radial keratotomy surgeries. Follow-up was obtained on 134 (68%) of these eyes. Mean spherical equivalent (SE) was -4.3 diopters before surgery, average keratometry was 44.11 D, and 75% of eyes had uncorrected distance acuity of 20/400 or worse. Average SE was -0.52 D for eyes seen at 5 years, which compares with -0.78 D for eyes examined at 18 months. Seventeen percent of eyes show at least a 1-D change in refraction from 18 months to 5 years compared with 13% between 18 months and 3 years. Fifty-six percent of eyes are within 1 D of emmetropia at 5 years, compared with 66% at 18 months. Uncorrected visual acuity was at least 20/40 in 62% of eyes seen at 5 years and in 73% of eyes seen at 18 months. Ten percent of eyes have lost at least two lines of best-corrected visual acuity from before surgery to 5 years later. Factors are identified that relate to loss of uncorrected and best corrected acuity over 5 years. Average keratometry at 5 years is 40.7 D, as compared with 41.2 D at 18 months. Long-term keratometric results appear less stable than refractive results and a theory for this instability is presented. The results indicate radial keratotomy to be safe and effective for the vast majority of patients in this series for 5 years postoperatively.