Mechanical reinforcement of the cornea with an intrastromal in‐situ photo‐polymerised implant.

Abstract

AbstractPurpose A photo‐polymerisable hydrophilic material (PEG/Irg) has been previously evaluated in terms of biocompatibility and toxicity in a series of laboratory animals. It was the purpose of this study to evaluate the bio‐mechanical effect of lamellar implants created from PEG/Irg in porcine cadaver eyes.Methods Twenty porcine corneas where removed along with a 3 mm corneoscleral rim, de‐epithelialised and mounted on an artificial anterior chamber. The pressure was maintained at 22 mmHg hydrostatically. In each cornea, a circular lamellar pocket (7mm diameter) was created manually. Thirty microliters of PEG/Irg in liquid form were injected in each pocket. A rigid contact lens was pressed on top of the cornea and the excessive quantity of PEG/Irg was leaked out of the pocket. The cornea was then irradiated with UV light (390nm, 4mW/cm2) and the PEG/Irg underwent a polymerization and the associated phase transition to form a rigid film. Mechanical measurements were performed by means of a purposely‐developed device featuring a stepping motor and a load cell. By keeping the pressure constant the role of corneal stiffness is isolated. The force as a function of indentation was recorded for each specimen before and after the in‐situ creation of the PEG/Irg film.Results The mean slope of force versus indentation for the reinforced group was 166.72 (±74.14) and the mean slope for the non‐reinforced group was 116.94 (±21.16). The two‐tailed P value equals 0.0033, equally meaning that the difference between those two groups was statistically different.Conclusion According to the results, there was a significant biomechanical reinforcement of the cornea following the in‐situ creation of the polymer film.