GLAUCOMA DRAINAGE DEVICES

GLAUCOMA DRAINAGE DEVICES &KERATOPROSTHESISDr. Neeraj AgarwalPg 3rd year

GLAUCOMA DRAINAGE DEVICES

Use for managment of recalcitrant cases of glaucoma.These work by creating an alternate pathway for aqueous outflow by channeling aqueous from the anterior chamber through the long tube of the implant towards subconjuctival space.

HISTORY1907- Rollet implant a horse hair thread connecting the anterior chamber to subconjuctival space near limbus. (Setons).Setons were unsuccessful as they were unable to maintain fistula patency

Molteno introduced 2 concept-1st- in 1969 molteno introduced the concept that large surface area is needed to disperse the aqueous. for this Molteno inserted a short acrylic tube attached to a thin acrylic plate, suturing it to the perilimbal sclera.2nd- in 1973 molteno threw light upon the importance of draining the fluid away from the source to increase the success rate.

Molteno implants however offer no resistance to the outflow and post operative complications like hypotony, flat anterior chambers and choroidal effusions were frequent phenomenon.

In 1976 KRUPIN & in 1993 MARTIN AHMED intoduced unidirectional pressure- sensitive valve that provide resistance to the aqueous flow.

GDD with No ResistanceSingle plate Molteno- silicone tube (0.62mm ext, 0.30mm internal), polypropylene end plate (135mm square) Double plate Molteno- second plate is attached to original end plate to double surface area.

Baerveldt Implant- made of medical grade silicone (barium impregnated) entirely (tube & plate)Episcleral plate have different surface areas- 200, 250, 350, 500 mm square.350 mm square is most preferred size.Plate has 2 fixation holes to allow growth of fibrous tissue and this add in scleral attachment.

Baerveldt Pars Plana Implant- it contains a 7mm long silicone tube connected to an elbow attached to anterior surface of the plate

Schocket Implant- a sialistic tube one end of which is inserted into the AC, and the other end is tucked beneath a No. 20 retinal encircling band.Ex-PRESS R50- single piece, stainless steel, trans limbal implant

GDD with Variable ResistanceThese are modified by incorporation of resistance mechanism dependent on tissue apposition to limit flow.Apposition is unpredictable so these offer variable resistance.

Molteno Dual Ridge Device- it limits drainage area by dividing the top portion of the plate into 2 separate spaces with a thin V-shaped ridge.

Baerveldt Bioseal- contain a flap overhanging the silicone tube at its insertion into the end plate.

FLOW RESTRICTED GDDAHMED glaucoma valve- AGV is a silicone tube connected to a valve of silicone elastomer membranes, held in polypropylene body.End plate 185mm squareValve designed to open when IOP is 8 mmhg.

Krupin Slit Valve- silicone tube with a slit valve attached to a silicone oval end plate.Surface area 180 mm squareOpening prassure of slit valve 11-14mmhgClosing pressure 2mmhg.

INDICATIONS OF GDD Neovascular glaucoma PKP with glaucoma Retinal detachment surgery with glaucoma ICE syndrome Traumatic glaucoma Uveitic glaucoma

Open-angle glaucoma with failed trabeculectomy Epithelial downgrowth Refractory infantile glaucoma Contact lens wearers who need glaucoma filtration surgery. Sturge Weber syndrome

CONTRAINDICATIONSEyes with severe scleral and or sclerolimbal thining. Extensive fibrosis of conjunctiva Ciliary block glaucoma

Relative C/IVitreous in anterior chamber Intraocular silicone oil- Implant if required is placed in inferotemporal quadrant

POST OP SequeleHypotensive phase: From day 1 to 3-4 weeks following the operation.Clinical examination during this phase reveals a diffuse and thick-walled bleb with minimally engorged blood vessels.The IOP is low (i.e., from 2-3 mm Hg to 10-12 mm Hg).

Hypertensive phase starts 3-6 weeks after the operation and lasts for 4-6 months.It is more commonly seen with the Ahmed Glaucoma Valve.This has been attributed to the smaller surface of the AGV. On examination, an inflamed and dome shaped bleb is seen, and increased IOP, at times greater than 30 mm Hg may be noted.

During the hypertensive phase, when the IOP is too high (usually >21 mm Hg), antiglaucoma medications may be initiated, along with digital massage. In case the patient doesnt respond needling may be indicated. A subconjunctival injection of 5-FU in the opposite quadrant may also be given.

Stable phase follows the hypertensive phase and is characterized by stabilization of intraocular pressure usually in the early teens

PostOp C/C-HypotonyLow IOP (