Hydrogel keratophakia: a freehand pocket dissection in the monkey model

Area of Science:

• Ophthalmology
• Biomaterials Science
• Corneal Surgery

Background:

• High water content hydrogels exhibit water and solute permeabilities similar to the corneal stroma.
• These hydrogels are biocompatible with corneal tissue.
• Effective intrastromal implants for refractive keratoplasty require alteration of the anterior corneal curvature.

Purpose of the Study:

• To investigate the efficacy of hydrogel lenticules as intrastromal implants for refractive keratoplasty.
• To assess the refractive and keratometric changes induced by implanted hydrogel lenticules.
• To determine the relationship between hydrogel lenticule parameters and corneal refractive alteration.

Main Methods:

• Hydrogel lenticules were implanted via free-hand pocket dissection in primate eyes (Macaca mulatta and Macaca nemestrina).
• Pre- and postoperative keratometry, subjective retinoscopy, and biomicroscopy were performed.
• Corneal refractive power changes were calculated based on lenticule parameters.

Main Results:

• The overall corneal refractive change was +3 +/- 27% (SD).
• The central keratometric change was +6 +/- 16% (SD).
• Implantation of hydrogel lenticules did not result in significant steepening of the anterior corneal surface.

Conclusions:

• Hydrogel lenticules implanted in a free-hand intrastromal pocket did not induce significant refractive changes.
• The current hydrogel lenticule design and implantation method are insufficient for effective refractive correction via corneal curvature alteration.
• Further research is needed to optimize hydrogel properties and implantation techniques for refractive keratoplasty.