SURGICAL TECHNIQUE

The KDB tip enters the anterior chamber through a temporal peripheral clear corneal incision and advanced to the nasal TM under direct gonioscopic visualization. The instrument’s sharp tip then engages TM, fashioning an opening through which heel at the base of footplate is seated in schlemm’s canal. Then, the tip is advanced within the canal along with TM, which is elevated onto the ramp and stretched as it is guided to two cutting blades that remove an intact TM strip. The strip is removed from the eye with KDB or with forceps. This elevation and stretching of the TM before excision maximizes the width of excised strip and protects adjacent structures from collateral injury.

STUDY POPULATION: Patients diagnosed with mild to moderate stage open angle glaucoma undergoing KDB goniotomy as a standalone or combined with phacoemulsification visiting the Glaucoma department of Nethradhama Super speciality Eye Hospital, Jayanagar, Karnataka willing to participate in the study.

 METHODOLOGY

The study will be conducted after approval by the institutional review board of Nethradhama Superspeciality Eye Hospital, Bangalore and will adhere to the tenets of declaration of Helsinki.

Procedure:

After obtaining informed consent from the patients enrolled in the study, baseline data including glaucoma type and severity, preoperative IOP, number of antiglaucoma medication [AGM] will be recorded. All surgeries will be performed by a single surgeon. Operative details will be noted. Patients will be followed up at 1 day, 1 week, 1, 3 and 6 months postoperatively. Safety will be assessed in terms of complications of the procedure. Success criteria are defined based on 20% IOP reduction or >/= 1 AGM reduction.

Excisional goniotomy is generally a safe procedure without significant sight-threatening complications. Transient bleeding from the TM excision site is common and typical of most angle based surgeries. The most common complications associated with excisional goniotomy are elevated intraocular pressure [3-32%], posterior capsule opacification [combined surgery][ 9%], transient pain [8%].

Unlike other glaucoma procedures, it does not require the implantation of a device, obviating secondary surgical procedures for device-related complications, and does not create a bleb, precluding the need for suture lysis, needling, and other postoperative bleb management procedures. Reoperation rate due to surgical failure is 2-22%, higher rates in patients with more severe glaucoma and/or higher baseline IOP.