Visual, refractive, and keratometric results of radial keratotomy. Five-year follow-up.

This article presents five-year findings on the first 156 radial keratotomies in our series. Results are compared with findings on these same eyes at one and three years and with results from other studies. Follow-up at five years was on 123 eyes (79%). Before surgery, the mean spherical equivalent was -5.0 diopters (D). Five years after surgery, the mean change in the spherical equivalent was 5.17 D, and 53% of eyes were within 1 D of emmetropia. Uncorrected visual acuity was 20/200 or worse in 96% of eyes before surgery. At five years, 36% had 20/20 acuity or better, and 75% were 20/40 or better. Best corrected acuity was at least 20/20 in 90% of eyes before surgery. At five years, 85% retained at least 20/20 best corrected acuity. Although some patients still have shown refractive and visual acuity changes through five years after surgery, the overall group has been stable.

Histopathology of traumatic corneal rupture after radial keratotomy.

Two patients (three eyes) had previously undergone technically successful radial keratotomy procedures and subsequently sustained blunt injury to the eyes in motor vehicle accidents one and two years after surgery, respectively, with rupture of the cornea along the keratotomy scars. One case subsequently required penetrating keratoplasty to recover 20/50 visual acuity. The second patient died, but had he survived, the extensive ocular injuries would have required significant surgical and medical care to restore vision. Histologic and ultrastructural studies demonstrated incomplete wound healing in the three corneas. Individuals who have had radial keratotomy, like those who have had penetrating keratoplasty, are at increased risk of corneal rupture after direct ocular trauma.

Corneal sensitivity after radial keratotomy.

Corneal sensitivity was tested in 76 eyes of 40 patients who underwent radial keratotomy for the correction of myopia, and radial keratotomy plus transverse incisions for the correction of myopia and astigmatism. There was a decrease in corneal sensitivity in 30.9 and 9.5% of patients undergoing radial keratotomy after 6 and 12 months, respectively. Approximately 70% of patients in this group had a recovery of lost sensitivity after 6 months. There was a similar decrease in sensitivity in 79.4 and 47.0% of patients undergoing radial keratotomy with the addition of transverse incisions for astigmatism at 6 and 12 months, respectively. The recovery rate in this group was 40.7%. The most significant loss of corneal sensation was in the areas central to the transverse incisions. The depth of the transverse incision, as well as the preoperative astigmatism, appeared to be factors in the loss of corneal sensation as well as in the recovery of the corneal sensitivity. There were no complications noted in this study as a result of decreased corneal sensitivity.

Contact lenses in the treatment of patients with overcorrected radial keratotomy.

Thirty-two eyes of 28 patients who underwent radial keratotomy had a hyperopic overcorrection after the surgical procedure. Anisometropia, with associated aniseikonia and depth perception problems were present in many of these patients. The patients were subsequently fit with contact lenses. Conventional methods of fitting contact lenses in these patients were unsuccessful. A trial lens technique is used with the initial lens having a base curve equal to the preoperative keratometry measurements and the power equal to the preoperative spherical equivalent. Superficial neovascularization developed within the radial incisions in 33% of the eyes fitted with soft contact lenses. Gas permeable contact lenses offered patients the best-corrected visual acuity as well as minimal complications. In addition, the anisometropia was minimized, and fluctuating vision was eliminated in cases in which it was a problem.

Visual, refractive, and keratometric results of radial keratotomy. A two-year follow-up.

We report two-year follow-up findings on 142 (91%) of the first 156 radial keratotomies performed. The results are contrasted with our earlier six-month and one-year results and with findings from other studies. Mean spherical equivalent before surgery was -5.0 diopters and two years after surgery was -0.10 D; 51% of the eyes were within 1 D of emmetropia. Uncorrected distance acuity was 20/200 or worse in 96% of the eyes before surgery. At two years, 39% had 20/20 acuity or better and 76% had 20/40 or better. At one year, 49% had 20/20 acuity and 76% had 20/40 acuity or better. Refractive results between one and two years showed an overall increase in mean spherical equivalent of 0.23 D. Our results indicate radial keratotomy to be relatively safe and effective two years after surgery.

Delayed keratitis after radial keratotomy.

A number of serious complications have been reported after radial keratotomy. In this article, we describe three episodes in two cases of delayed keratitis after radial keratotomy. The keratitis was noted nine months, 35 months, and 40 months after radial keratotomy. Delayed wound healing and epithelial inclusion cysts are likely causes. To our knowledge, this is the first report in the literature of delayed keratitis occurring as a late complication after radial keratotomy.

Evaluating the predictability of radial keratotomy.

The predictability of radial keratotomy surgery for both the steel and diamond knife cases is evaluated in a long-term prospective study. Over 500 cases are used to build predictability models for both types of knives at 1, 3, 6, and 12 months after surgery. A predictability model is also presented at 24 months after surgery for the steel knife. R2 values range from 54 to 80% for the various models. Over 75% of cases are predicted within 2 D of their obtained result for the steel knife at all time periods and over 78% for diamond knife cases. Each model is also evaluated for how well it predicts future cases.

Visual, refractive, and keratometric results of radial keratotomy. One-year follow-up.

Ongoing prospective evaluation of radial keratotomy was conducted on 156 eyes of the first 101 consecutive patients. We did a one-year follow-up and compared previously reported six-month findings. All eyes were examined both six months and one year after surgery. Findings obtained by an independent examiner both before and after surgery correlated highly with findings obtained in the surgeon's office. One year after surgery, mean change in spherical equivalent was +4.7 diopters; overall uncorrected distance acuity was 20/20 in 49% of cases and at least 20/40 in 76% of cases. Fifty-eight percent of eyes were within 1.0 D of emmetropia. Visual results showed slight general improvement between six and 12 months; refractive results were stable, except that excessive overcorrection was found to decrease. In this series, radial keratotomy seemed safe and effective one year after surgery.

Psychosocial findings in radial keratotomy patients two years after surgery.

In a psychosocial study of patients who participated in an evaluation of the visual, refractive and keratometric results of radial keratotomy, respondents stated that their primary reasons for electing the operation related to anticipated changes in vision. Improving appearance was not reported as a primary reason for seeking radial keratotomy by these patients. When asked two years after surgery if their vision had improved, remained the same, or worsened, 94.3% reported improvement over preoperative vision. About 40% still wear corrective lens, 26% full time and 14% only part of the time. Most patients (84.1%) reported overall satisfaction with the surgical outcome. Patient satisfaction was strongly related to perceived improvement of vision after surgery, and not to patient self-esteem, to changes in appearance or lifestyle brought about by the operation, or to having a particular physician perform the surgery.

Visual, refractive, and keratometric results of radial keratotomy.

Prospective evaluation of radial keratotomy was conducted on 156 consecutive eyes of 101 patients. Before surgery, mean spherical equivalent (SE) was -5.0 diopters and uncorrected distance acuity was 20/200 or worse in 96% of eyes. All eyes were examined six months after surgery. Overall six-month postoperative distance acuity was 20/20 in 43% and 20/40 or better in 73% of eyes; 51% of eyes were within 1.0 D of emmetropia; mean change in SE was +4.8 D. When preoperative myopia was less than 6.0 D, six-month uncorrected acuity was 20/20 in 53% and 20/40 or better in 84% of eyes; 63% were within 1.0 D of emmetropia. Visual, refractive, and keratometric findings appeared stable at six months. Predictability appeared best when preoperative myopia was less than 6 D. Complications were few, none resulted in reduced best-corrected acuity, and most were transient and/or well tolerated. In this series, radial keratotomy appeared safe short-term. Ongoing evaluation is being conducted to determine long-term safety and efficacy.