Photochemical Cross-Linking for Penetrating Corneal Wound Closure in Enucleated Porcine Eyes.

PURPOSE: To compare the efficacy of photochemical-induced tissue cross-linking (PCL), utilizing Rose Bengal (RB) and 532 nm green light irradiation (RB-PCL), with standard sutures for closure of penetrating corneal incision in porcine cadaver eyes.

METHODS: A full-thickness penetrating incision, 3 mm in length parallel to the limbus and perpendicular to the corneal surface, was made in the enucleated porcine cornea. Photochemical cross-linking was performed with tropical RB application and irradiation of 532 nm green light (0.6 W/cm2 ) for 200, 250, and 300 seconds at laser fluences of 120, 150, and 180 J/cm2 , respectively, which was compared with the standard 10-0 nylon suture group. Following treatment, intraocular pressure to the point where wound leakage occurred (IOPL ) was measured. Corneal central thickness and surface temperature before and after PCL treatment were recorded. Optical coherence tomography (OCT) and scanning electron microscopy (SEM) were utilized to evaluate wound closure.

RESULTS: The mean corneal central thickness was increased from 812.0 ± 47.0 to 838.0 ± 45.6 µm after the incision as a result of cornea aqueous humor infiltration. RB penetrated approximately 140 μm into the porcine corneal stroma. The mean IOPL for untreated blank group after incision was 4.27 ± 0.36 mmHg. Increased laser fluences produced increased IOPL of 27.02 ± 3.01 (PCL120 ), 31.60 ± 3.67 (PCL150 ) and 36.73 ± 3.25 mmHg (PCL180 ), which were statistically different from the control intact group. The mean IOPL in the sutured cornea was 57.30 ± 4.59 mmHg. The average surface temperature difference before and after PCL treatment was 2.03 ± 0.45-2.47 ± 0.79°C. OCT demonstrated not only complete but also improved closure in comparison with disorganized collagen fibers after conventional suturing, which is further confirmed by SEM.

CONCLUSIONS: Complete and clinically relevant seal of full-thickness porcine corneal incision was achieved using PCL method ex vivo, which provides potential application of this technique in ocular wound closure.