Penetrating Keratoplasty vs. Epikeratoplasty for the Surgical Treatment of Keratoconus

PURPOSE

Penetrating keratoplasty and epikeratoplasty have been utilized in the surgical treatment of keratoconus. Comparison of the relative efficacy of each procedure in achieving visual outcomes has not been achieved due to limited numbers of cases and follow-up in previous series.

METHODS

All patients who underwent either penetrating keratoplasty or epikeratoplasty for keratoconus between January 1987 and December 1997, and for whom at least 24 months of postoperative follow-up data for visual acuity was documented in the medical record, were included in this retrospective, nonrandomized, sequential comparative trial. The sole criteria for outcome in each group, as well as for comparison of the two groups, was Snellen visual acuity measured at the time of each follow-up with the presenting optical aid.

RESULTS

Inclusion criteria were met for 443 eyes treated with penetrating keratoplasty and 161 eyes treated with epikeratoplasty. Mean follow-up was 4.3 years for penetrating keratoplasty and 4.5 years for epikeratoplasty. In each group, approximately 50% of the patients chose rehabilitation with optical correction with either spectacles or contact lenses and 50% chose no optical correction. Final median logMAR visual acuity for all patients, irrespective of means of visual rehabilitation, was 0.30 (20/40) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). In 209 penetrating keratoplasty and 77 epikeratoplasty eyes with optical correction, the final median logMAR visual acuity was 0.18 (20/30) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). The final median logMAR visual acuity in 234 penetrating keratoplasty and 84 epikeratoplasty eyes without optical correction was 0.48 (20/60) in both groups (P-value was not statistically significant).

CONCLUSIONS

Although penetrating keratoplasty was statistically superior to epikeratoplasty with respect to visual outcome, results with epikeratoplasty were adequate to recommend its use as a surgical alternative in cases when it is not desirable to perform penetrating keratoplasty.

Corneal transplant for keratoconus: results in early and late disease

PURPOSE

To evaluate the results and complications rates associated with corneal transplantation for keratoconus and assess the prospects of using penetrating keratoplasty at a much earlier stage.

SETTING

Buzard Eye Institute, Las Vegas, Nevada, USA.

METHODS

In this prospective clinical study, 104 eyes of 76 patients had corneal transplantation for keratoconus identified by corneal topography, keratometry, pachymetry, and/or retinoscopy. Sutures were removed at a mean of 15 months; mean follow-up was 42 months. All surgeries were performed by one surgeon using a torque-antitorque suture method. Eyes were grouped according to severity of the disease: early (n = 24); moderate (n = 47); high (n = 33). Preoperative keratometry was 40.00 to 49.00, 50.00 to 59.00, and 60.00 to 90.00 diopters (D), respectively. The criteria for corneal transplant were a best spectacle-corrected visual acuity of 20/40 or worse and keratoconus clearly identified by one of the above methods. Secondary procedures included repair of wound dehiscence (33 eyes, 31%), relaxing incisions (33 eyes, 31%), wedge resections (5 eyes, 5%), and automated lamellar keratoplasty (4 eyes, 4%).

RESULTS

Mean postoperative uncorrected visual acuity at last follow-up was 0.43 +/- 0.3 (20/50), with 46 eyes (44%) achieving 20/40 or better. Mean best corrected visual acuity (BCVA) at last follow-up was 0.83 +/- 0.2 (20/25). Sixty eyes (58%) achieved 20/40 or better BCVA at 1 month and 92 eyes (88%), at 3 months. At last follow-up, mean average keratometric astigmatism was 3.10 +/- 1.70 D, mean keratometry was 43.30 +/- 2.20 D, and mean spherical equivalent was -1.70 +/- 3.00 D. Complications included 21 graft rejections (20%); 19 were successfully treated with topical and oral steroids. No expulsive hemorrhage or endophthalmitis occurred.

CONCLUSIONS

The risk-benefit for corneal transplantation has been significantly altered by improved surgical and postoperative techniques. The improved results, low complication rate, and postoperative enhancement management indicate that corneal transplantation is a viable option early in the clinical course of keratoconus.

Management of perforations during epikeratoplasty for keratoconus

Epikeratoplasty (EKP) in keratoconus generally has few intraoperative complications. Perforations during EKP are rare but may force the surgeon to abandon the procedure. We developed a special suture technique to manage this problem. Several deep mattress sutures are placed by taking shallow bites of the central corneal rim and deep bites of the peripheral corneal rim. This leaves the peripheral corneal rim projecting forward by approximately one third the corneal thickness. Slight stretching of this peripheral corneal rim allows adaptation of the epilenticule to form a smooth tissue plane. This method was used in two patients with significant corneal scarring and led to satisfactory visual results.

Wedge resection in the cone after failed refractive surgery in a patient with keratoconus

A 30-year-old man with keratoconus in the right eye had radial keratotomy in the left eye. Two pairs of corneal relaxing incisions (CRIs) were made in the right eye to flatten the central cornea and reduce high astigmatism. The right eye required an enhancement, and two additional arcuate CRIs were made. A corneal ulcer developed in the right eye, with infiltrates in the incision and corneal thinning. Although the second set of CRIs resulted in more regular astigmatism, the corneal thinning and ulcer caused regression at two months postoperatively. A wedge resection was performed to even the irregular astigmatism. The results are presented.