Decorin in Sub Scleral Trabeculectomy

Study design:

This is a prospective, single-center, interventional, randomized controlled study at Kasr Al Aini Teaching Hospital, Cairo University. Patients with medically uncontrolled glaucoma will be enrolled in our study.

Fifty two consecutive eyes with Primary Open-angle Glaucoma indicated for trabeculectomy will be enrolled in the current study and will be then randomly assigned to our interventions. Informed consent will be obtained from all patients before any intervention. Uncontrolled glaucoma was defined as uncontrolled IOP (≥22 mm Hg) measured with a Goldmann applanation tonometer under maximal tolerable medical treatment with visual field defect progression. Exclusion criteria will include patients with history of intraocular surgery within the previous 6 months, patients with history of surgery involving the conjunctiva, angle closure glaucoma, and patient refusal to take part in the study.

Data Collected:

Preoperative:

Preoperative information that will be collected will include the patient's age, sex, previous ocular procedures, number of glaucoma medications, last recorded intraocular pressure (IOP), ocular comorbidity, and best corrected visual acuity (VA).

Adjuvant Decorin:

Recombinant human decorin will be provided by the manufacturing company (R\&D Systems, Inc., Minneapolis, MN, USA) reconstituted in a vial at 0.4% concentration using phosphate-buffered saline as a vehicle.

Surgical Procedure:

In Decorin group: 26 patients will receive subconjunctival injection of 100 µg decorin 15 minutes before surgery. A30-gauge needle was used to inject 100 µL of decorin. The needle was placed at the nasal margin of the superior rectus muscle, so that a visible bleb was formed on the supranasal quadrant.

A corneal traction suture will be taken, followed by fornix-based conjunctival dissection and gentle diathermy.

Mitomycin Group: MMC will then be applied in 26 patients to the sclera at a concentration of 0.3 mg/ml using cellulose sponges, which will be removed after 3 minutes followed by copious irrigation with balanced saline solution (BSS).

A half to three-quarter thickness, rectangular scleral flap will be dissected. Four grooves will be created into clear cornea near the limbus to accommodate the releasable sutures then two preplaced releasable sutures will be taken at the corners of the scleral flap using 10/0 nylon sutures. The corneal traction will then be released and the trabeculectomy ostium will be created using a 0.75 mm Kelly's punch (Katena Products Inc., Denville, NJ) followed by a peripheral iridectomy (PI). The two releasable sutures will be tied, and BSS was used to form the anterior chamber. More releasable sutures will be taken in the middle of the scleral flap until watertight closure is achieved. The conjunctival incision will then be closed by 2 purse string sutures at the sides and one mattress suture at the limbus, using 10/0 nylon sutures.

Topical prednisolone 1% eyedrops will be used every 2 hours for 2 weeks, 6 times daily for 2 weeks, then tapered gradually over the following 2 months. Topical moxifloxacin 0.5% will be given 5 times daily for 2 weeks.

In Decorin group: postoperative days 1, 3, and 7, patients will receive subconjunctival injection of decorin. A30-gauge needle was used to inject 100 µL of decorin at the nasal margin of the superior rectus muscle.

Postoperative:

Patients will be seen after 1 day, 1 week, 1 month, 3 months, 6 months, 9 months and 12 months, with more frequent visits in uncontrolled or complicated cases. IOP and visual acuity measurements will be recorded every visit. Any complications of surgery will be reported.

Primary outcome measure is success of trabeculectomy defined as complete if the IOPis≤ 21 mm Hg without medications and qualified where antiglaucoma therapy is required to maintain it at such a level. Failure will be defined as an IOP> 21 mmHg on medications, need for another glaucoma surgery or loss of light perception.

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