Microkeratome-assisted lamellar keratoplasty for the surgical treatment of keratoconus.

PURPOSE

To evaluate the visual and refractive results of microkeratome-assisted lamellar keratoplasty (LK) performed on keratoconus patients intolerant to spectacles and contact lenses.

DESIGN

Prospective, noncomparative, interventional study.

PARTICIPANTS

A microkeratome-assisted LK procedure was performed on 50 eyes of 50 keratoconus patients. All patients were spectacle and contact lens intolerant.

INTERVENTION

All patients included in this study underwent a standard surgical procedure involving removal of a lamella (9 mm in diameter cut with the 250-microm microkeratome head) from the recipient cornea by means of a hand-driven microkeratome and suturing of a donor lamella (0.5 mm smaller in diameter than the removed corneal lamella, cut with the 350-microm microkeratome head) obtained from a cornea mounted on an artificial anterior chamber. Each patient was examined preoperatively and at different postoperative times (1 and 6 months and 1, 2, 3, and 4 years).

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), 1-year best contact lens-corrected visual acuity (BCLCVA), refraction, and computerized analysis of corneal topography.

RESULTS

After suture removal was completed, both UCVA and best-corrected visual acuity were significantly improved over properative values at all examination times. One year postoperatively, when follow-up was still available for all patients, UCVA was better than 20/200 in 8 of 50 (16%) patients and BSCVA was > or =20/40 in 44 of 50 (88%) patients, whereas BCLCVA was > or =20/40 in all 50 patients. Refractive astigmatism within 4 diopters was seen in 43 of 50 (86%) patients. Corneal topographic patterns were classified as regularly astigmatic in 39 of 50 (78%) patients. The 1-year values did not change substantially at later postoperative examination times. Complications included preparation of donor grafts of poor quality that needed to be discarded (8 cases [16%]), irregular astigmatism of various degrees (11 cases [22%]), high-degree astigmatism requiring secondary intervention (6 cases [12%]), epithelial interface ingrowth (1 case [2%]), and cataract formation (1 case [2%]).

CONCLUSIONS

Microkeratome-assisted LK can be performed on corneas with moderate to advanced keratoconus with a minimal corneal thickness of >380 microm. The procedure is relatively simple, may be standardized in most of its parts, and does not involve time-consuming maneuvers. All complications recorded did not threaten vision and were dealt with successfully. Our results indicate that microkeratome-assisted LK is as efficacious as conventional penetrating keratoplasty for the surgical treatment of keratoconus. However, the time necessary to achieve stable results is considerably shorter.