Alloplastic implants for the correction of refractive errors.

Convex-shaped, hydrophilic lenticles of various water content were implanted into microkeratome-dissected corneal pockets in a baboon model. Freshly trephined, cryolathed, and factory-lathed hydrogels were evaluated for periods exceeding 15 months, documenting clinical response, corneal curvature shifts, and morphologic features. Previously implanted hydrogels were subsequently removed, documenting the reversibility of the procedure while allowing the corneas to return to their preoperative condition. Various alloplastic materials were then reimplanted into the same intrastromal pockets. Medium and high water content lenses produced good results without affecting the recipient cornea, whereas thick or low water content materials extruded or produced severe anterior segment inflammation. The use of medium and high water content, convex-shaped lenticles for the correction of aphakia is possible using current techniques.