Richard H. Keates

Clinical Management of Keratoconus: A Multicenter Analysis

The clinical management of 746 eyes in 417 patients referred for keratoconus from January 1984 through January 1988 was retrospectively analyzed. In 357 patients, 554 eyes (74%) did not require surgery and were managed with contact lenses or spectacles, 156 eyes (21%) in 137 patients either underwent penetrating keratoplasty (PK) (140 eyes) or surgery was recommended (16 eyes), and 36 eyes (4%) in 34 patients underwent epikeratoplasty. Comparing baseline and final examination findings, the nonsurgical group showed a significant improvement in average best-corrected visual acuity from 20/30 to 20/25, the PK group from 20/70 to 20/25, and the epikeratoplasty group from 20/40 to 20/30. Average keratometry was unchanged in the nonsurgical group, but decreased by 10.7 diopters (D) for the PK group and 6.5 D for the epikeratoplasty group. Corneal cylinder was unchanged in the nonsurgical group, whereas there was a reduction of the percentage of eyes with indeterminant cylinder from 55 to 2% in the PK group and from 36 to 0% in the epikeratoplasty group. Previous contact lens history, best-corrected visual acuity of 20/50 or worse, and average keratometry of 55 D or greater at baseline were associated with a significant risk for PK. No baseline variables were associated with significant risk for epikeratoplasty, suggesting that this group was similar to the nonsurgical group, except for contact lens intolerance. The nonsurgical management of keratoconus continues to play a predominant role in the management of this disorder in a referral population.

Long-term follow-up of Nd:YAG laser posterior capsulotomy

A Nd:YAG laser developed for ophthalmic surgery was studied for safety and efficacy in secondary discission of the posterior capsule in aphakic and pseudophakic subjects. The study involves 6,800 subjects, 526 of whom had completed the six-month postoperative course by the time the data base was closed for analysis. Of the 526 subjects who were treated with the laser, 87.8% had improved vision, with 82.9% achieving a visual acuity of 20/40 or better. This result compares favorably with results for the surgically treated population in which only 68.4% experienced improved vision, with 80.2% achieving a visual acuity of 20/40 or better. Approximately four times more surgically treated subjects than laser-treated subjects experienced diminished vision (14.8%). Cumulative complication rates in the laser-treated population were very low (CME 2.3%, secondary glaucoma 3.6%, retinal detachment 0.4%, overall rate 4.8%). Persistent complications (present at the six-month postoperative period) were present at an overall incidence of 2.3%, comprised primarily of CME, 0.2%, retinal detachment, 0.2%, and secondary glaucoma, 0.8%. Only 5.7% of subjects experienced an intraocular pressure (IOP) rise to 30 mm Hg or greater. Return to the preoperative IOP level occurred in 89% of subjects in the first 24 hours to one week. Predictors of IOP rise to 30 mm Hg or greater were determined to be preoperative glaucoma and/or preoperative IOP of greater than 20 mm Hg.

Clinical results of the multifocal lens

ABSTRACT The multifocal posterior chamber intraocular lens was implanted in 46 eyes of 38 patients as part of the first clinical trial of this target‐type implant. No major complications were reported. Visual acuity results for distance and near vision were excellent, with best case visual acuities better than 20/40 in over 95% of eyes in the first three months.

The Nationwide Study of Epikeratophakia for Aphakia in Children

In the nationwide study of epikeratophakia, 97 surgeons performed a total of 335 procedures in 314 eyes for the correction of aphakia in children under the age of 8 years 1 month. Fifteen children underwent bilateral surgery. Thirty-six tissue lenses were removed and 21 of these eyes underwent a second epikeratophakia procedure. Overall, the success rate for procedures was 89%, and with repeated surgery it was 95% for eyes. Seventy-three percent of the patients were within 3 diopters of emmetropia after surgery. Visual acuity results in patients able to provide verbal responses to the illiterate E, Allen card, or Snellen line chart testing showed improvement in most cases. The safety of epikeratophakia makes it a desirable option for the correction of aphakia in children who are spectacle or contact-lens intolerant, and the permanence of the correction eliminates the problem of optical noncompliance.

The Nationwide Study of Epikeratophakia for Aphakia in Adults

In the nationwide study of epikeratophakia, 154 ophthalmic surgeons who had attended a training course performed 519 procedures for the correction of aphakia in adults: 310 of the eyes had 30 or more days of follow-up after suture removal. Of 229 eyes, 172 (75%) were within 3 diopters of emmetropia after surgery. Of 259 eyes, 245 (95%) demonstrated improved uncorrected visual acuity; 138 (53%) improved by four or more Snellen lines. Of 265 eyes, 209 (78%) achieved within two lines or improved their best corrected visual acuity. Of the 119 patients who achieved or improved their preoperative best corrected visual acuity, 110 (92%) were within two Snellen lines or better by 30 to 60 days after suture removal. Of the 127 patients with more than three months of follow-up after suture removal, 124 (98%) of those between 18 and 70 years of age but only 13 of 23 (54%) of those between 81 and 87 years of age achieved within two lines or better of their best corrected visual acuity. Corneal astigmatism measured by keratometry changed from a preoperative mean (+/- S.D.) of 2.1 +/- 1.8 diopters to a postoperative mean of 2.7 +/- 2.6 diopters. Of the 519 tissue lenses, 22 (4%) were removed, and one third of these patients underwent a second, successful epikeratophakia procedure.

The nationwide study of epikeratophakia for myopia

In the nationwide study of epikeratophakia, 116 ophthalmic surgeons performed 352 procedures for the correction of myopia; 256 of the eyes had 30 or more days of follow-up after suture removal. Of 204 eyes, 153 (75%) were within 30% of emmetropia after surgery. Of 208 eyes, 202 (97%) had postoperative best corrected visual acuity within two Snellen lines or better of their preoperative visual acuity. All but one patient improved uncorrected visual acuity. Of the 120 patients who equaled or improved their preoperative best corrected visual acuity, 116 (97%) were within two Snellen lines of their preoperative measurement between 30 and 60 days after suture removal. Corneal astigmatism changed from a preoperative mean (+/- S.D.) of 1.4 +/- 0.8 diopters to a postoperative mean of 2.6 +/- 2.1 diopters. Of 352 tissue lenses, 36 (10%) were removed, largely as a result of inaccurate power, decay, or failure to reepithelialize, and 17 of these eyes underwent a second successful epikeratophakia procedure.

Epidermal growth factor and insulin use in corneal preservation : results of a multi-center trial

Purpose: The ability of DexSol medium, supplemented with two growth factors, human epidermal growth factor (hEGF) and human insulin, to improve long-term endothelial survival after penetrating keratoplasty was evaluated in a multi-center, randomized, prospective, double-masked clinical trial. Methods: Donor cornea pairs, one stored in DexSol and the other in DexSol with hEGF (10 μg/ml) and human insulin (10 pug/ml) (ProCell), were transplanted into 105 pairs of recipients matched by diagnosis and procedure and followed postoperatively for graft and endothelial survival. Results: No primary donor failures occurred in either group. Graft clarity did not differ between the ProCell and DexSol groups at all postoperative periods: 3 months (98% versus 99%), 6 months (94% versus 98%), and 1 year (95% versus 97%), respectively. Postoperative complications (e.g., glaucoma, rejection) occurred with comparable frequencies in both groups. Mean endothelial cell loss did not significantly differ between the ProCell and DexSol groups at 3 months (5.7% versus 5.1%), 6 months (8.1 % versus 10.1 %), and 1 year (12.3% versus 15.6%), respectively. Similarly, there were no clinically and statistically significant differences in other endothelial morphometric parameters. Conclusions: The use of corneas stored in DexSol medium with added hEGF and insulin in corneal transplantation resulted in a safety and efficacy profile comparable with that observed in patients receiving DexSol-stored corneas; however, there were no clinically and statistically significant differences in postoperative endothelial morphometric parameters.

Effect of the Nd:YAG laser on polymethylmethacrylate, HEMA copolymer, and silicone intraocular materials

ABSTRACT Recent trends of cataract extraction feature both small surgical wounds and preservation of posterior capsules. The development of safe, reliable, and flexible implant materials that can withstand near impact with a Nd:YAG laser during secondary posterior capsule discissions are required. An in vitro experiment was performed to analyze the effects of Nd:YAG laser irradiation on polvmethyl methacrviate (PMMA), hydroxyethylinethacrylate (HEMA), hydroxyethylhydroxymethyl methacrylate (HEMA‐MEMA) copolymer com bination, and a silicone compound. The HEMA and HEMA‐MEMA compounds were the least susceptible to Nd:YAG laser damage in this laboratory setting.

The Nationwide Study of Epikeratophakia for Aphakia in Older Children

A nationwide study of epikeratophakia for aphakia in older children was conducted from March 1984 to March 1986. Sixty-three patients, 8 to 18 years of age, underwent this procedure in 65 eyes. Twenty-eight patients had congenital cataracts and 35 had traumatic cataracts. Fifty-one of the 65 eyes were aphakic at the time of surgery (secondary procedures). All surgeries were successful; no tissue lenses were lost or removed. Postoperatively, 73% of the patients were within 3 diopters (D) of emmetropia. The patients with congenital cataracts gained an average of one Snellen line of best-corrected visual acuity; patients with traumatic cataracts lost an average of one Snellen line of best-corrected visual acuity. In older pediatric patients, epikeratophakia appears to be a safe and effective procedure for the correction of aphakia.

Ultraviolet Light Transmission of the Lens Capsule

A Cary, Model 118, spectrophotometer was used to measure spectral absorbence by the human lens capsule of wavelengths 200 nm to 400 nm. The lens capsule transmits greater than 90% of the incident UV light, and thus does not appear to provide significant protection for the retina from UV radiation. This suggests that the lower incidence of aphakic cystoid macula edema in the eye with an intact posterior capsule is not related to UV light absorption by the lens capsule.