use of a modified compression shell after subscleral trabeculectomy

ABSTRACT

To determine the influence of a modified compression shell [with a cut out free space for the cornea] in guarded filtration procedures on flat anterior chambers, final intraocular pressure [IOP] reduction, success rate, tenon capsule cyst [TCC] and bleb appearance in patients with primary open angle glaucoma, we randomized in a prospective clinical trial 33 patients divided into two groups Group A, 15 patients in whom the shell was applied immediately postoperatively; and group B, 18 patients without shell. Both groups were similar in age, sex, diagnosis and preoperative IOP. The shell was applied at the end of each surgery and used for three days postoperatively. There was no statistical difference after surgery in the incidence of flat anterior chamber [2/15 in group A and 3/18 in group B]. Also, there was no difference after three months in term of bleb appearance, but there was a tendency of fewer TCC in those receiving the shell [1/15 in group A and 3/18 in group B]. After two years there was no statistical difference in IOP reduction or in success rate in either group [73.5 percent group A and 72.5 percent group B]. Success is defined as 5 mmHg <22, with reduction of medication and no carbonic anhydratse inhibitors