Do scleral flap dimensions influence reliability of intraocular pressure control in experimental trabeculectomy?
AIM: To compare the effect on intraocular pressure (IOP) of large vs small scleral flap size during trabeculectomy using adjustable sutures. METHODS: Trabeculectomy operations were performed on nine donor human eyes connected to a constant flow infusion with real-time IOP monitoring. Large scleral flaps (4 x 4 mm, 16 mm(2), n=12) or small scleral flaps (3 x 2 mm, 6 mm(2), n=9) were constructed over 0.76 mm(2) sclerostomies. For each procedure, equilibrium IOP was measured following tight closure with two four-throw adjustable 10-0 nylon sutures. RESULTS: Five scleral flaps were thin or poorly constructed; four of these were in the initial seven procedures, implying learning effect. These had a mean absolute IOP of 7.6 mmHg (range 2.7-12.4 mmHg) and mean relative IOP of 28.3% of baseline (range 10-45.8%) after closure. In the remaining 16 good quality procedures, mean IOP was 1.3 mmHg (range 0-3.4 mmHg) after sclerostomy, confirming minimal outflow resistance before closure. Following f
