Abstract
Abstract: :
Purpose: To describe a novel glaucoma drainage device (GDD) which drains aqueous humor to the external ocular surface. Methods: The device consists of a Silastic tube with a beveled end lying in the anterior chamber. The tube passes through the limbus and lies on the episcleral surface for 4–7 mm beneath a pericardial patch graft, Tenon’s capsule, and conjunctiva before exiting through conjunctiva into a tolerable component lying on the external ocular surface in the conjunctival cul–de–sac beneath the lid. A micro–pore filter spans the lumen of the tube and is linked to the external component of the device. The micro–pore filter protects against microbial invasion and provides appropriate resistance to set the intraocular pressure (IOP) at the desired postoperative target. An inserting device is designed to properly place the device (with a pre–placed pericardial patch) into the eye through conjunctival and limbal puncture wounds without requiring incisions or sutures. The external component coupled with the micro–pore filter is replaceable and enables postoperative adjustment of IOP as needed. A very early prototype of this GDD was implanted into 1 eye in each of 3 cynomolgus monkeys with laser–induced glaucoma, with follow–up of at least 8 months in each monkey. The contralateral control eyes underwent standard trabeculectomies. Preoperative IOPs were > 25 mmHg in all eyes. Results: Postoperative IOPs were maintained lower than 15 mmHg in all 3 eyes with the GDD, but rose to > 20 mmHg within 1 to 4 weeks in the 3 control eyes. Pseudomonas aeruginosa was repeatedly applied to the external aspect of the GDD in one eye without producing an endophthalmitis, whereas the same strain injected into a rabbit eye produced a fulminant endophthalmitis. Conclusions: This novel GDD enables a simple and quick insertion process, a guaranteed barrier against infection, and a predictable and adjustable postoperative IOP without a bleb or dependence on the vagaries of wound healing. Clinical trials will determine its relative utility in the management of glaucoma.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • intraocular pressure • anterior segment