This document summarizes different types of glaucoma drainage devices (GDD) used to manage refractory glaucoma. It describes the history and evolution of GDDs from early seton implants to modern implants with resistance mechanisms to control aqueous outflow. The key GDD types discussed are Molteno, Baerveldt, Ahmed, and Krupin valves. Complications, indications, success rates, and outcomes are compared between devices. The document also reviews keratoprosthesis procedures used to replace severely damaged corneas.

1. Dr. Neeraj Agarwal
Pg 3rd year

2. GLAUCOMA DRAINAGE DEVICES

3.  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.

4. HISTORY
 1907- 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

5. 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.

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

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

8. GDD
No
resistance
Variable
Resistance
Flow
Restricted

9. GDD with No Resistance
Single 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.

12. 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.

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

17.  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

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

20.  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.

22. FLOW RESTRICTED GDD
 AHMED glaucoma valve- AGV is a silicone
tube connected to a valve of silicone elastomer
membranes, held in polypropylene body.
 End plate 185mm square
 Valve designed to open when IOP is 8 mmhg.

25.  Krupin Slit Valve- silicone tube with a slit valve
attached to a silicone oval end plate.
 Surface area 180 mm square
 Opening prassure of slit valve 11-14mmhg
 Closing pressure 2mmhg.

27. INDICATIONS OF GDD
 • Neovascular glaucoma
 • PKP with glaucoma
 • Retinal detachment surgery with glaucoma
 • ICE syndrome
 • Traumatic glaucoma
 • Uveitic glaucoma

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

29. CONTRAINDICATIONS
 Eyes with severe scleral and or sclerolimbal
thining.
 Extensive fibrosis of conjunctiva
 Ciliary block glaucoma

30. Relative C/I
 Vitreous in anterior chamber
 Intraocular silicone oil- Implant if required is
placed in inferotemporal quadrant

31. POST OP Sequele
 Hypotensive 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).

32.  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.

33.  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 doesn’t respond needling may be indicated.
 A subconjunctival injection of 5-FU in the opposite
quadrant may also be given.

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

35. PostOp C/C-
Hypotony
Low IOP (<5 mm Hg) with a shallow AC in the immediate
postoperative period may due to:
• Overfiltration
• Wound leak
• Choroidal effusions
Hypotony due to overfilteration is seen is 20-30% of the
cases with non valved implants. Modifications like
placement of a suture in the lumen of the tube (ripcord
technique) have been devised to lower its incide

36. Tube obstruction
The obstruction may be caused by blood, fibrin, vitreous, or
iris plug, or it could be related to a tight external ligature
around the tube.
It manifests as an intraocular pressure rise associated with a
deep anterior chamber

37. Managment of tube obstruction
 Blood or fibrin clot: Intracameral injection of 5-10 mg of
tissue plasminogen activator (TPA) in 0.1 mL of BSS.
 Vitreous incarceration- Nd:YAG laser to dissipate the
vitreous strands.
 Iris incarceration- peripheral argon laser iridoplasty
(applied to the base of the plug).
 •Tight external ligature can be cut with argon laser

38. Tube retraction
Retraction of the tube from the anterior
chamber may be managed by placing an
extender sleeve with a larger inner diameter
over the existing tube

39. Diplopia
 Diplopia and strabismus was noted to be significantly
higher (18%) with the Baerveldt implant than with the
AGV (3%) or the Molteno implant (2%).
 This difference is attributed to the unique design of the
Baerveldt implant, because of its large size.
 The placement of the reservoir plate beneath the 2
adjacent rectus muscles and incorporation of the adjacent
recti into the bleb are the incriminating factors.
 Persistent diplopia might require removal of the implant

40. Corneal decompensation
 The 10-20% incidence of corneal decompensation
seen after the GDD implanatation, is a dreaded
complication of this procedure and a significant cause
of poorer long term visual outcome.
 The causative factors are the tube-corneal touch and
chronic low-grade inflammation from the presence of
the silicone tube in the AC leading to endothelial
damage.

41. Tube-corneal touch mandates repositioning of
the tube

42. Graft failure
 GDD surgery appears to be associated with a
high incidence of graft failure (10-51%) in
patients with corneal graft associated with
glaucoma.

43. Tube and end plate exposure
 Cases with end plate exposure may require
conjunctival autograft or pericardial patch graft
sutured to the Tenon capsule.
 Cases with tube exposure may require a scleral or
pericardial patch graft to cover the tube, followed by a
conjunctival autograft

44. Suprachoroidal hemorrhage
 Clinically, pain with increased IOP in the operated eye either
during the operation or in the postoperative period indicates a
possible suprachoroidal hemorrhage.
 Clinical signs include a shallow AC, increased IOP, and
choroidal elevations that appear darker than choroidal
effusions.
 B mode usg is usually helpful in making this diagnosis

45.  The incidence of suprachoroidal hemorrhage among
the different GDDs is similar.
 Management of suprachoroidal hemorrhage includes
supportive therapy, followed by topical and oral
steroids, glaucoma medications, cycloplegic agents,
and painkillers.

46. Indications for drainage of suprachoroidal
hemorrhage-
 Involvement of the macula by the hemorrhage
 Kissing choroids
 Corneo-lenticular touch
 Severe pain.

47. Late failure
 Has been attributed to multiple factors including chronic
lowgrade inflammation causing fibrosis of the bleb,
fibrosis of the valve or the outlet of the nonvalved
implants, extrusion of the end plate or the tube from
conjunctival melt, or infection.

48. Endophthalmitis
 Endophthalmitis following a GDD operation is very
rare- with a reported estimated incidence of less than
2% and is more common through thin-walled blebs or
areas of aqueous leakage, in children and following
needling of the bleb.

49. Loss of vision
Loss of vision by 2 or more lines can occur in 20-40% of
patients following GDD surgery. This may be related to the
various complications
 Suprachoroidal hemorrhage
 Corneal edema
 Endophthalmitis
 Cataracts
 Progression of glaucoma
 Band keratopathy
 Cystoid macular edema

50. comparison
 The overall surgical success rate averaged between 72%
and 79% among the five devices with no statistical
significant difference at the last follow-up (p=0.94).
 All five implants significantly lowered intraocular
pressure.
 There were no statistically significant differences in
either the percentage change in intraocular pressure or
the overall surgical success rate.
 Diplopia was seen more frequently with the use of the
Baerveldt implant.

51.  In conclusion, with advent of newer models of GDD in the
market, although the predictability has increased but is
still far from perfect.
 The venture continues in search for a totally inert
biomaterial that will not attract fibroblast or protein
deposits.
 Also research is directed towards minimizing the fibrous
reaction around the bleb with new drugs that target the
inflammatory factors.

52. keratoprosthesis

53. KERATOPROSTHESIS
 Keratoprosthesis refers to an artificial corneal
device used in patients unsuitable for
keratoplasty
 This is a surgical procedure where a severely
damaged or diseased cornea is replaced with an
artificial cornea to restore useful vision.

54. Indications
 Stevens-Johnson syndrome
 Ocular cicatricial pemphigoid
 Epidermolysis bullosa
 Chemical injury
 Thermal injury
 Trachoma
 Multiple failed penetrating keratoplasties
 Aniridia with severe corneal changes
 Corneal failure after vitrectomy with silicone oil filled
eyes

55. contraindication
 Absent light perception (absolute)
 Age below 17yr
 RD or Posterior segment pathology
 Mentally unstable pt.
 Unavailibility for long term f/u
 Unreasonable cosmotic or visual expectations
 Edentulous pt (for OOKP, absolute)

56. Preop evaluation
 A detailed history to determine the primary diagnosis and
previous surgical interventions is recorded.
 A brisk perception of light and normal B- scan are essential
pre-requisites.
 An inaccurate projection of rays (PR) is not a contraindication,
as a severely disturbed ocular surface may itself lead to
inaccurate PR.
 Electrodiagnostic tests can be done to aid in the assessment of
the visual potential.
 Intraocular pressure is usually assessed by digital tonometry as
other forms of measurement give erroneous readings on a
disturbed ocular surface.

57. TYPES OF
KERATOPROSTHESIS
Based on material used to fix central optic part-
 BOSTON KPro(TYPE 1 AND 2) :-
 The Boston Type I Kpro is the most widely used device.
 The Boston Type II Kpro
 AlphaCor Kpro
 OSTEO-ODONTO KPro(OOKP)

59. BOSTON KPro-
2 Types
 Type 1:- More commonly used. Used in eyes that
have sufficient wetting function to maintain the
corneal tissue in which the Kpro is placed.
 Type 2:- Used in very dry eye with minimal or no
tear production.

60. Type 1
collar button design
 There is a front plate and back
plate sandwiching a fresh
donor corneal graft
Titanium locking ring is used
to secure the front And back
plates and corneal complex to
prevent Any Inadvertent
Unscrewing of the complex.

61. Type 2
 The type 2 device is of a similar design, with an added
anterior cylinder that protrudes through a permanently
closed upper eyelid, and is used in end-stage dry eye
 Back plates holes are important to allow the nutrients to
reach the graft keratocytes from the aqueous

62. ALPHA COR KPRO
 The AlphaCor first being implanted in human eyes in
1998 and receiving FDA approval in 2003.
 Manufactured from a single biocompatible polymer,
poly hydroxyethyl methacrylate (pHEMA)
 two zones, a clear central optical core and an opaque
spongy skirt, made by polymerizing the pHEMA under
conditions of differing water content
 The ability of the outer skirt to be colonized by
invading keratocytes resulting in integration of the
device with surrounding tissues

63. Modified Osteo-Odento
Keratoprosthesis
 The OOKP was first described by Strampelli in 1963.
 Later modified by Falcinelli and Coll.
 It uses the patient’s own tooth root and surrounding alveolar
bone to support a centrally cemented optical cylinder.
 Multi staged procedure, surgery in mouth and eye.
 Use of a wide single rooted tooth with surrounding alveolar
bone acts as carrier for a PMMA optical cylinder, which is
covered by buccal mucous membrane,

64. Stage 1
 Full thickness Mucous Membrane
Graft harvested from the buccal
mucosa.
 Graft is sutured over damaged cornea.
 It has stem cells,high proliferating
Capacity and adapted to high Bacterial
load

65.  Followed by Preparation of the Osteodentalacrylic Lamina
(ODAL)
 A single rooted tooth, preferably the upper canine is chosen
for preparation of the lamina.
 The tooth with the surrounding alveolar bone is extracted.
 Then sliced sagitally and Central hole is drilled
 customized PMMA optical cylinder is cemented
 ODAL is then placed in the subcutaneous pouch in the
orbitozygomatic area for next 3 months to develop
vascularization and to promote the growth of connective
tissue.

66. STAGE 2
 This is performed 3 months after stage 1
 The Graft is dissected off from the subcutaneous pouch
and examined for its integrity.
 The central cornea is trephined according to the posterior
diameter of the cylinder.
 The Graft is placed with the cylinder centered over the
corneal trephination and sutured.
 The Mucous Membrane Graft is finally reflected back on
the lamina with a central trephination through which the
anterior cylinder protrudes out.

67. Post operative Management
 Topical Antibiotics daily for 3-4 weeks.
 Medroxy Progesterone (1%) 4 times a day in 1st month
then 2 times a day to reduce tissue necrosis.
 Sub-Tenons injection of 20-40mg Triamcinalon if eye
shows an inflammatory reaction.
 Systemic Antiglaucoma drugs
 Initially weekly followup, after 6 months once every 2
months.

68. Prognosis
Best:
• Multiple Graft failure in a relatively non-inflamed eye
with intact tear and blink mechanisms (following
dystrophies, infections, etc)
• Aniridia and other limbal stem cell failure cases
Intermediate:
• Chemical burns, HSV
Worst:
• Autoimmune diseases
• Mucous membrane pemphigoid
• Stevens-Johnson syndrome
• Chronic uveitis

69. Complications
 MELTS AND EXTRUSION
 INFECTIOUS ENDOPHTHALMITIS
 GLAUCOMA
 RETRO PROSTHETIC MEMBRANES
 RETINAL DETACHMENT
 OTHERS

70. MELTS AND
EXTRUSION
 Occur at the base of Boston Kpro
 SLE and anterior segment OCT are helpful in detection of
corneal thinning around KPro
 If melts are seen then replace the whole thing with fresh
graft and put new KPro
 In MOOKP, resorption of buccal mucosa can occur,new
graft can be placed
 Resoprtion of osteo odonto lamina can occur,serial CT
scan yearly
 If resorption of dentine has occurred it should be replaced

71. INFECTIOUS ENDOPHTHALMITIS
 Dreadful complication following kpro surgery
 Treatment:- includes leak repair, injection of
antibiotics and topical antibiotics
 if Fungal infection suspected change contact lens and
give topical amphotericin and systemic anti fungals
required

72. GLAUCOMA
 Single most serious complication following surgery
leading to irreversible loss of vision due to chronic low
grade inflammation, progressive angle closure, anterior
displacement of iris have been implicated.
 Topical Treatment is effective in Boston type 1 Kpro.
 Systemic Treatments can be used with Boston type 2 and
MOOKP.
 Tube shunts and endoscopic cyclophotocoagulation have
been successfully used.

73. RETRO PROSTHETIC MEMBRANES
 Most commonly reported
 Occurs in 25-64% of pts in 1 yr follow up
 These fibrous membranes originate from activated
host stromal cornea cells that migrate through gaps in
the posterior graft–host junction
 More prevalent in individual with chronic
inflammation such as autoimmune diseases and
uveitis.

74. t/t of retroprosthetic membrane
 Majority may not require treatment
 Nd yag capsultomy following by steroids in 90% cases
 If membrane thick, leathery and vascularised - Sx
management
 For Boston kpro membranectomy can be performed
 Removal of prosthesis and replacement with new one is
preferred

75. RETINAL DETACHMENT
 Most common posterior segment complication, an
incidence of 16.9 %
 Surgical Rx with buckle or vitrectomy
 Choroidal detachments can also develop in eyes with
Kpro.

76. Recent Advances
 Stanford Keratoprosthesis :-
 Kpro is based on a mechanically enhanced
Hydrogel called Duoptix
 It supports the growth of epithelial cells.
 Surrounding the optic is a microperforated rim
designed to promote peripheral tissue integration
 Collagen Based Keratoprosthesis
 Designed to mimic the extra cellular Matrix of
corneal stroma

77.  Chondro-keratoprosthesis- is fixed with pts own
cartilage.
 Onycho-keratoprosthesis- fixed with pts nail.

78. THANK YOU