Epikeratopiasty

Iris Claw Phakic Intraocular Lens for High Myopia

BACKGROUND

The implantation of a Worst-Fechner iris claw intraocular lens (IOL) is one of the surgical procedures used for the correction of high myopia. This technique reduces myopia with stable refractive results; however, its potential long-term risks have not been evaluated. We report results in 94 eyes with a minimum follow-up of 3 years.

METHODS

We studied 94 eyes of 62 patients with myopia > or = -7.00 diopters (D) who underwent Worst-Fechner IOL implantation. Lens decentration, permeability of the blood-aqueous barrier by iris angiography, and changes in corneal endothelial density were analyzed.

RESULTS

Mean follow-up time was 48.9 months (range 36 to 72 mo). Three years after surgery, 58 eyes (61%) had an uncorrected visual acuity > or = 20/40, and 77 eyes (82%) gained two or more lines of spectacle-corrected visual acuity with respect to the preoperative value; 75 eyes (79%) were within +/- 1.00 D of emmetropia and 46 eyes (48%) were within +/- 0.50 D of emmetropia. The mean endothelial cell loss was 17.9% at 5 years after surgery, while the percentage of hexagonality and the coefficient of cell variation tended toward preoperative levels. No vision threatening complications were seen.

CONCLUSIONS

The implantation of a Worst-Fechner iris claw phakic IOL reduced high myopia with a stable refractive outcome. Endothelial cell damage was within acceptable limits. The absence of major complications makes this procedure an acceptable method for correcting high myopia.

Epikeratophakia for keratoconus. Long-term results using fresh, free-hand made lamellar grafts

Epikeratophakia using fresh, free-hand made corneal grafts was done in 16 patients with keratoconus. The follow-up period averaged 27.8 months (range 13-45 months). A significant improvement of visual acuity was obtained (p = 0.002), and 14 of the 16 eyes (87.5%) achieved a corrected visual acuity greater than or equal to 6/12. The spherical equivalent and the cylindrical refractive error were reduced (p less than 0.05), and a significant flattening of the central corneal curvature was obtained (p less than 0.002). The mean postoperative central corneal astigmatism was 4.25 D. Postoperatively, the mean central corneal thickness was 0.670 mm, and the mean central thickness of the epithelialized graft was 0.336 mm. Six patients reported some postoperative glare or blurring of vision, despite a visual acuity greater than or equal to 6/9 on the Snellen chart. No significant subjective or objective changes were noticed after the 6-month postoperative follow-up visit.

Epikeratophakia for high myopia

A cryo-technique for production of corneal epi-lenses has been developed. During the manufacturing procedure the anterior surface of the tissue is moulded and the posterior surface cut with a microtome. After cutting, the epi-lenses are stored for days to weeks in an organ culture medium. Twelve eyes in 10 patients have been treated with epikeratophakia for high myopia (greater than -7 D). In all eyes, epithelialization was complete within one week, and at follow-up 3-18 months after the operation all epi-lenses were clear. The average refractive change in spherical equivalents was 9.7 +/- 4.4 D. All eyes obtained better uncorrected visual acuity, and no eyes lost more than one line of the best corrected visual acuity. At the time of follow-up, the patients' native cornea had regained normal hydration, whereas the epi-lenses did not thin as much as expected.