Correction of hyperopia with intracorneal implants.

PURPOSE

To evaluate the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia.

SETTING

Al-Azhar University, Cairo, Egypt, and Louisiana State University Eye Center, New Orleans, Louisiana, USA.

METHODS

PermaVision lenses (Anamed Inc.) were implanted in the left eye of 20 albino rabbits that were followed for 6 months by confocal microscopy. The lenses are made of a highly permeable hydrogel with 70% water content and a refractive index close to that of corneal tissue (1.376). The Carriazo-Barraquer microkeratome (Moria) was used to create a 150 microm corneal flap with a diameter of 8.5 mm or larger. The intracorneal lens was placed under the flap after minimal interface irrigation.

RESULTS

At 3 days, confocal microscopy showed interface edema that resolved after 1 week. No flap melting or excursion of the lens was noted. In 1 eye, a deep lamellar keratitis was seen. At 6 months, the edge of the lens showed excellent compatibility, with no keratocytic activity or intrastromal fibrosis.

CONCLUSIONS

Intracorneal hydrogel lenses were well tolerated by stromal tissue in rabbits. They are potentially safe and can be considered as an alternative for the correction of hyperopia. Further clinical studies are required to confirm their safety in humans.