The authors describe and present results of a conjunctival-sparing, sutureless, ab interno glaucoma procedure that uses a gonoiscopically controlled 360-degree trabeculotomy. The procedure was safe and found to be effective in 68 to 90 percent of eyes in a variety of clinical settings.
The technique, which they call gonioscopy-assisted transluminal trabeculotomy (GATT), consists of placing a catheter or suture into Schlemm’s canal by way of a goniscopically controlled internal approach. The suture is placed into the canal with micro-forceps from within the anterior chamber, thereby resulting in a 360-degree trabeculotomy. The procedure requires an open angle allowing good visualization of the trabecular meshwork and scleral spur.
This approach certainly has many distinct advantages but requires excellent gonioscopic skills and would appear to have a definitive learning curve. Its main advantage is the sparing of the conjunctival tissue. It also eliminates the the possibility of external bleb fibrosis.
The authors used the procedure in 85 patients with uncontrolled open-angle glaucoma. All patients had at least six months’ follow up.
In the 57 patients with primary open-angle glaucoma, IOP decreased by 7.7 mm Hg, with an average decrease in glaucoma medications of 0.9 at six months. At 12 months, IOP decreased by 11.1 mm Hg with 1.1 fewer glaucoma medications.
In the secondary glaucoma group of 28 patients, IOP decreased by 17.2 mm Hg with an average of 2.2 fewer glaucoma medications at six months. At 12 months, IOP decreased by 19.9 mm Hg with an average of 1.9 fewer medications.
Treatment was considered to have failed in 9 percent of patients because of the need for further glaucoma surgery. The cumulative proportion of failure at one year ranged from 0.1 to 0.32, depending on the group. The most common complication was transient hyphema, seen in 30 percent of patients at the one-week visit.