Jackie Tan, Leslie John Ray Foster, Frank James Lovicu, Stephanie Louise Watson

Purpose: To investigate whether laser irradiation, used to activate an adhesive for sealing penetrating corneal incisions, causes any ophthalmoscopically or histologi- cally visible retinal changes.

Methods: Baseline fundus assessment was conducted prior to laser irradiation of eyes of pigmented Dutch- belted rabbits. Treatment group consisted of 18 eyes with the corneal adhesive activated in situ by a near infrared laser (125 mW for 45 seconds). A positive control group of 18 eyes were irradiated for 60 seconds with the same laser at 375, 500, 625 and 750 mW at different retinal locations. Unexposed regions of the retina were used as negative internal control. Ophthalmoscopic assessment was conducted immediately after laser exposure and prior to euthanasia. Retinas were histologically assessed at 0, 3, 72 and 168 hours after treatment.

Results: There were no ophthalmoscopically or histologically visible retinal changes observed in the treatment group immediately, nor up to 168 hours after laser irradiation. In the positive control group, the incidences of ophthalmoscopically visible retinal lesions increased with irradiation power: 5.6% at 375 mW, 16.7% at 500 mW, 44.4% at 625 mW and 50% at 750 mW. Histologically, retinal dam- age in the form of coagulative necrosis in all layers of the neural retina, including the retinal pigment epithelium, was observed, corresponding to the ophthalmoscopic findings.

Conclusion: The laser irradiation process used in the corneal adhesive technology did not cause any ophthalmoscopically or histologically visible retinal changes in the in vivo pigmented rabbit model. Prolonged exposure with this laser and at higher power can cause coagulative necrosis to the retina.