Erbium: YAG Laser Sclerostomy in Rabbits

The present study investigates the effects of the new Erbium:YAG(yttrium aluminum garnet) laser sclerostomy in eight rabbits eyes. The energy was set at 10mJ per pulse with the frequeny of 10Hz, and the total energy for the full thickness sclerostomy procedure was rated at 90 to 150ml. Following the procedure, the mean intraocualar pressure was significantly reduced for up to 7 days, and the histopathological observation at day 7 revealed clearly demarcated wound margins at the resected sites. The sesults suggest that te Erbium:YAG laser sclerostomy may be a good supportive procedures to conventional treatment of glaucoma.

Aqueous and Vitreous Concentration of Mitomycin C Administered Topically after Holmium Laser Sclerostomy in Rabbits

Mitomycin C is an antibiotic isolated from the broth of Streptomyces caespitosus which has been used as the adjunctive drug to reduce the fibroblast proliferation. Holmium laser sclerostomy can minimize conjunctival damage. We examined pharmacokinetics of mitomycin C following topical administration. Holmium laser sclerostomy was performed on one eye of each 15 rabbits and the other eye was served as a control. Next day, mitomycin C solution(0.4mg/ml) was administered by topical drops in both eyes of each rabbit. The concentrations of mitomycin C in the aqueous and the vitreous compartments of operated and control eyes were determined by HPLC at 0.5, 1, 2, 3, 6 hours after topical administration. The peak aqueous concentration was 0.07 microgram/ml in operated eyes and 0.06 microgram/ml in control eyes. The peak vitreous concentration was 0.10 microgram/ml in operated eyes and 0.09 microgram/ml in control eyes. The levels of detected mitomycin C at all time intervals were higher than the IC50(0.002 microgram/ml) for the inhibition of conjunctival fibroblast proliferation. These results suggest that topical mitomycin C easily crosses the intact and minimally damaged conjunctiva and therefore increases the success rate of Holmium laser sclerostomy.

Diode Laser Ab Externo Sclerostomy in Rabbits

Sclerostomy is preferable full-thickness filtration surgery, if very low pressure are desired or if guard filtration surgery had failed. Laser sclerostomy can be performed in a less invasive manner than standard procedure, so it reduces scar formation and minimizes postoperative complications. The objective of this investigation was to determine the feasibility and parameters of laser sclerostomy using a diode laser. The diode laser with a fiberoptic delivery system is lightweight, portable and utilizes a 100 Volt outlet. Eighteen eyes of pigmented rabbits underwent a diode laser ab externo sclerostomy with energy 2 W, duration 1-2 seconds by applying endolaser probe, 0.5 mm from the limbus. Gross and histopathologic examination were done at 1 hour and 7 days after treatment. A patent fistula with formation of filtering bleb was achieved in all cases. There was a flattening of the filtration bleb at 3.3 postoperative days.