May 22, 2002
Enzymatic Sclerostomy
Arch Ophthalmol May 2002;120:548-553
The potential of collagenase to act as a "biological knife" to selectively digest collagen inspired researchers to develop a treatment modality for glaucoma "enzymatic sclerostomy". For this purpose, highly purified collagenase (nucleolysine) is used to create deep focal scleral digestion, possibly enabling micropercolation of aqueous humor.
Enzymatic sclerostomy was performed in 15 blind symptomatic eyes of 15 patients with primary open-angle glaucoma under topical or peribulbar anesthesia. A specially designed polymethylmethacrylate enzyme applicator filled with a mean of 123 µg of collagenase was introduced through a 5-mm peritomy, and affixed to the limbus by means of cyanoacrylate tissue glue. After 22 to 24 hours, the applicators were removed and the patients were followed up for 1 year.
| By causing an overall decrease of 43.0% in the IOP immediately after treatment and a sustained lowering effect of 20.0% at 1 year without antiglaucoma medication, enzymatic sclerostomy has demonstrated its potential as a treatment for open-angle glaucoma. |
| Patients were equally comfortable under topical anesthesia or with peribulbar block, suggesting that enzymatic sclerostomy could be performed as an office procedure. |
Controlled thinning of the treated sclera associated with aqueous percolation and shallow filtration bleb was seen in all eyes in the immediate postoperative period. The mean IOP decreased from 43.5 mm Hg (with antiglaucoma medications) preoperatively to 24.8 mm Hg (a 43.0% decrease from baseline with no antiglaucoma medication) on the first postoperative day and to 34.8 mm Hg (a 20.0% decrease from baseline with no antiglaucoma medication) at the end of 1 year. Sustained lowering of the IOP was achieved despite the absence of a detectable filtering bleb in most eyes beyond 1 month and in all eyes beyond 3 months. It is possible that enzymatically induced alterations in the walls of Schlemm canal and the trabecular architecture, could contribute to the IOP–lowering effect. Ophthalmic adverse effects were limited to the treated area and included immediate postoperative transient conjunctival reaction ranging from mild chemosis to conjunctival maceration. No systemic complications were noted. None of the patients reported pain or discomfort during and after the procedure.
In summary, enzymatic sclerostomy has demonstrated its potential as a relatively simple surgical treatment for glaucoma. It demonstrated immediate and sustained IOP reduction and provided symptomatic relief in blind eyes with primary open-angle glaucoma. The procedure, however, needs further technical refinement.
Posted by dastjerdi at May 22, 2002 07:24 AM