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SCLERAL FLAP ELEVATION BY FILTRATION ENHANCING KNOT IN TRABECULECTOMY
(Papers on this subject presented at Nuremberg Germany, AIOS conference Kolkata)

In trabeculectomy, IOP is lowest on post operative day one & there is a danger of anterior chamber becoming shallow or flat. Target Pressure is achieved only later after healing & scarring takes place. To overcome this problem of flat AC, filtration-enhancing knot can be of great help. We can keep IOP above target pressure in the initial post operative period & filtration can be enhanced thereafter as per requirement, simply by elevating scleral flap, holding the filtration enhancing knot. Patient can be discharged on same day.

Procedure :-
Limbal based conjunctival flap is made (fig. 1). Then routine trabeculectomy surgery is done. Before suturing superficial scleral flap, suture using 8-0 nylon is passed through conjunctiva one mm away from limbus & in the region of center of superficial scleral flap, then through tenons, then partial thickness of scleral flap & out through tenons & conjunctiva (fig. 2). A loose knot is tied on conjunctiva fig. 3. Then trabeculectomy wound closure is done in usual fashion fig. 4 aiming postoperative pressure slightly higher than the target pressure. After 4 days the IOP is measured. If bleb is small then suture passed through the scleral flap is pulled slightly to elevate scleral flap & conjunctiva, which will cause aqueous to leak below conjunctiva & will be visible as bleb.
This should bedone under topical anaesthesia on slit lamp or operating microscope. Every fourth day patient is called till the IOP is blow target pressure & bled is good for consecutive three visits. If it is not, then by pulling the scleral suture & routine suturolysis can be done. Usually the suture taken through superficial scleral flap (8 zero nylon) is removed after one month.