Surgery in open angle glaucoma
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Surgeries in open angle glaucoma
Presenter: Dr.Aditi Singh
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Indications:
1.Documented visual field and optic nerve damage, despite maximum
tolerated medications and laser therapy.
2. Anticipated progressive damage or intolerably high IOP.
3. Combined with cataract procedure if there is borderline IOP control or advanced damage,.
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:
guarded (trabeculectomy)
Penetrating filterationg surgeries
full-thickness
Nonpenetrating filtration surgery(NPFS)
Glaucoma Drainage Devices (GDD)
Recent advances in glaucoma surgeries
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Full-Thickness Filtration Procedures
1.Thermal sclerostomy (scheie Procedure).
2.Sclerectomy
3.Trephination
4.Iridencleisis
Rarely performed today.
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1.Thermal sclerostomy (scheie Procedure): • Limbal-based conjunctival flap.
• Light cautery applied to the sclera in 1X 5 mm area , behind corneolimbal junction.
• 5 mm limbal scratch incision is made through the cauterized area.
• Cautery is applied to the lips of the incision , until the wound edges separate by atleast 1 mm.
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2. Sclerectomy: Posterior lip sclerectomy:• Ab-externo incision- just behind the point of
reflection (using a limbal-• based flap) of the conjunctiva at the anterior
limbus.• Length - 3–4 mm• Sclerectomy - 1-mm scleral punch • Peripheral iridectomy• Closure
Anterior lip sclerectomy:• Incision - at the corneoscleral sulcus • Excise the 1-mm semicircle of tissue.• Button holing of the conjunctival flap .
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• 3.Trephination:• Corneoscleral trephination, using a 1–2-
mm glaucoma trephine, is a difficult procedure.
• Performed only occasionally.
4.Iridencleisis:• Wedge of iris is incarcerated into the
limbal tissue . The presumed mechanism was a ‘wicking’ of aqueous by the iris tissue.
• However, reports of chronic iritis, infection,
and sympathetic ophthalmia led to other techniques being explored
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Complications:
• Shallow (or flat) anterior chambers:
• Peripheral anterior synichae,
• Corneal decompensation.
• Premature cataract formation,
• and infections.
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Guarded Filtration Procedure: Trabeculectomy :
Introduced by: Cairns in the 1960s. Indications: • Intraocular pressure too high to prevent
further glaucoma damage and• functional visual loss.• Documented progression of glaucoma damage
at current level of intraocular• pressure with treatment.• Presumed rapid rate of progression of
glaucoma damage without intervention.• Poor compliance with medical therapy: cost,
inconvenience, understanding of• disease, refusal.• Intolerance to medical therapy due to side
effects.•
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Anesthesia
• General anesthesia
• Local : Retrobulbar local block, peribulbar block , subtenon’s, or
• Topical anesthesia in selected cases.
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Technique Clear corneal traction suture: • 7-0/ 8-0 vicryl• half thickness • 2 mm anterior to the limbus.
The Conjunctival Flap:
Site: Superior and slightly nasal.
Both limbus and fornix based conjunctival flaps
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Limbus-Based FlapAdvantages:• allows tight wound
closure.• relatively easy to
master.
Disadvantages:• ‘migrates’ towards
the limbus.
• more chances of incapsulated bleb.
Fornix-Based Flap
Advantages: • easier exposure of
the surgical site • reduced handling of
the conjunctival flap.
Disadvantages: • longer operative
time.
• may leak in the postoperative period and fail to retain aqueous, so that the bleb flattens.
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Antimetabolites :
Agents 5-FU inhibits DNA synthesis and RNA
function; usual intraoperative dose is 50 mg/mL.
MMC alkylates DNA and inhibits DNA and RNA synthesis; usual dose is 0.2–0.4 mg/mL.
Prepare sponges: cut to size and then soaked in the antimetabolite
Place sponge under the conjunctival flap (and under scleral flap in resistant cases) for appropriate duration (5 min for 5-FU; 2–4 min for MMC)
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Scleral Flap
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The anterior chamber is entered under the flap, and a block of tissue
approximately 1.5–2.5 mm wide is removed with a Descemet’s punch just
anterior to the scleral spur.
Removal of the trabeculectomy block too posterior to the scleral spur offers no
advantage and increases the risk of hemorrhage
Peripheral iridectomy.
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Flap Suturing
The scleral flap is reapproximated with 9-0 or 10-0 nylon sutures .
Releasable suture
Peng Khaw’s adjustable suture technique allows a titrated outflow
A careful running suture in two layers, first closing Tenon’s and then its overlying conjunctiva at the limbus.
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Postoperative lasering, adjustment, or release of sutures :Argon green, argon blue-green, diode, YAG
laser or krypton red laser. Four-mirror Zeiss gonioprism or with the
Hoskins laser suture lens .
High-magnification suture lysis contact
lenses are commercially available (e.g., Mandlekorn lens or Blumenthal lens )
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Complications and management:
Complications
Intra-operative Post-operative
Early Late
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Intraoperative Complications
Conjunctival button hole
Scleral flap damage
Vitreous loss
Flat anterior chamber:choroidal hemorrhage , choroidal
expansion,aqueous misdirection
Bleeding:Conjunctiva, sclera,iris or
suprachoroidal
Prevention: non toothed forceps
Management: small : spontaneous healing (with hold steroid drops)focal (1-2mm) : closure with 10-0 nylon
Before or after sclerostomy
Management: Before sclerostomy: new siteAfter sclerostomy : Minor : suturing with 10-0 nylonSevere : scleral patch graft , tenon’s capsule , fascia lata
Causes: thin sclera( buphthalmic eye), aphakia, post trauma, lens dislocation.
Management : anterior vitrectomy
Preoperatively:Identify the risk factors.
Discontinuation of anticoagulants.
Intraoperatively:Topical apraclonidine 1 % or adrenaline
Minimal handling of tissues
Maintain intraoperative IOP.
Management :All wounds should be promptly closed
Reformation of the anterior chamber
SCH extensive: drainage of blood by
emergency
pars plana sclerostomy
• Choroidal expansion: secure the wound; Perform posterior sclerotomy that does not perforate choroid , administer atropine.• Suprachoroidal hemorrhage:Recognize vitreous loss; secure the wound; perform posterior sclerotomy over choroidal elevation area to drain blood; administer atropine
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Postoperative complications
Early
Shallow AC
High IOP
Low IOP
Infection
Blebitis Endophthalmitis
Wipe out phenomenon
Early
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Shallow AC
Low IOP
Formed Bleb
Flat Bleb
Over filtration
Causes:• Antimetabolites • Loose sceral flap sutures• Full thickness procedures
Management :• Cycloplegics • +/- aqueous suppressants• Decrease steroids• Pressure patching• Simmons shell, SCL
Flat AC:• Reformation :• Visoelastics / BSS• Large choroidal effusions may need drainage
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Shallow AC
Low IOP
Flat Bleb
Wound LeakPressure patch Temporary tapering of
topical steroids Large diameter SCL Cyanoacrylate Glue Injection of autologous
bloodSurgical repair (larger
holes)Conjunctival autograft
Indian J Ophthalmol. 2011 January; 59
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Shallow AC
Low IOP
Serous choroidal detachment
• Due to Hypotony
• Prolongs the hypotony
• Vicious cycle
Management :• Cycloplegics , topical steroids• Surgery :• Kissing choroidals• Flat AC , compromised cornea• Eyes with chronic angle closure glaucoma with extremely shallow AC, after trabeculectomyDellaporta Technique
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Low IOP
CB Shutdown
• Excessive inflammation Steroids Atropine• Avoid beta blockers, CAI
inhibitors
Cyclodialysis cleft
• Identify with gonio or UBM• Atropine, decrease steroids• Argon laser with Goldmann
lens• Treat the scleral region of
the cleft• For large cleft, definitive
management is surgical repair
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Shallow AC
High IOP
Pupillary block Suprachoroi
dal heamorrhag
e
Malignant glauma
• Non patent PI
• Management:
Laser PI
Mydriasis
Topical steroids
• Dark choroidal swelling
• Typical symptoms:
• sudden loss of visionpainnausea and/or
vomiting
• Diagnosis• Indirect • B-scan
• Management• Aqueous
suppressants,• Hyperosmotics ,
Pain relief,• Drainage
• Very shallow or flat central AC
• Look for patent iridotomy
• Aqueous suppressants
• Cycloplegics, topical steroids
• YAG anterior vitreous face (aphakic/pseudophakic)
• Pars plana vitrectomy
• Vigorous surveillance
• Attention to the fellow eye.
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• Filtration failure:• Obstruction of the sclerostomy and scleral
flap may be internal (incarceration of iris, ciliary processes, or vitreous), scleral (fibrin, blood),
• or external (overly tight scleral flap sutures). • Consider bleb massage, removal of
releasable suture(s), loosening of adjustable suture(s), and argon laser lysis of fixed suture(s).
• Visual loss: • Wipe-out of the remaining field may occur in
the presence of a vulnerable optic nerve (associated with increased IOP or hypotony) or
• Hypotonous changes may lead to reduced acuity (e.g., from maculopathy).
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Infection
Blebitis: - a painful red eye, possibly with mucus discharge and photophobia.
The bleb is milky with loculations of pus,
conjunctival injection (especially around thebleb), and increasing IOP.
Identify organism with culture/swab of bleb. Treat with intensive topical antibiotics and systemic
antibiotics.
Consider addition of topical steroids after 24 hours and add mydriatic if AC activity is present.
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Endophthalmitis:
Clinical features are the same as for blebitis but are more severe, with decreased VA and vitritis. Investigate and treat as for other postoperative endophthalmitis.
However, endophthalmitis occurring after trabeculectomy tends to run a more aggressive course with a worse prognosis than after cataract surgery.
c
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Late postoperative complications
a)Leaking bleb: antimetabolite-associated or nonguarded filtration surgery
Small leaks : often resolvesOtherwise, : consider bandage contact lens,
autologous blood injection, compression sutures, or refashioning of bleb.
b)Infection:(blebitis/endophthalmitis). c)Visual loss: Cataract .There can also be
induced astigmatism, maculopathy, and glaucomatous progression.
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Failure of the Filtering Bleb:Early Failure of Filtering Bleb:Presentation: high IOP, deep anterior chamber,
and low and hyperemic bleb.
Preventive measures:
Postoperative topical steroids are routinely used. The use of antifibrotic agents.
Manoeuvres to improve bleb function:Digital ocular compression and focal compression Laser suture lysis or removal of an externalized
releasable suture
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Late Failure of Filtering Bleb:
Most common cause : subconjunctival-episcleral fibrosis .
Factors accelerating fibrosis are: black race, childhood, postoperative
subconjunctival hemorrhage, the presence of reactive sutures, and inflammation.
“Warning signs” - increased bleb vascularization, bleb inflammation, and/or bleb thickening, high IOP.
Treatment : In cases of subconjunctival-episcleral fibrosis
- an external revision or blebneedling can be tried along with
antimetabolites.
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Encapsulated Blebs:Localized, elevated, and tense filtering blebs,
with vascular engorgement of the overlying conjunctiva and a thick connective tissue
Tenon’s cystSecond to fourth postoperative week as a
tense, “tight-appearing”bleb.
Temporary IOP reduction : aqueous suppressants .
Bleb needling with antimetabolites is an option in case of sustained raised IOP.
Failing all measures, a surgical bleb revision (partial/ complete cyst excision) or repeat trabeculectomy may be required, especially in cases of multiloculated cysts.
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Other bleb related complications:
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Complications….Cataract: flat anterior chamber
reformation of the anterior chamber with air lens trauma inflammation the use of – steroids , intraoperative
MMC
Ptosis : superior rectus bridle suture MMC damage to superior rectus.
Astigmatism: large scleral flaps. radial flap sutures.
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Glaucoma Drainage Devices
Indications:• Failed trabeculectomy• Extensive conjunctival scarring• Likely failure of trabeculectomy, including - • Neovascular glaucoma• Uveitic glaucoma• Glaucoma associated with penetrating
keratoplasty• ICE syndrome• Epithelial downgrowth• Refractory pediatric glaucoma
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Valved
• Only drains fluid at a certain IOP.
• Valve opens and fluid is drained into a reservoir where it is absorbed by surrounding tissues(e.g., Krupin or Ahmed valves).
Non- Valved
• Nonvalved implants or open tube drainage devices provide little resistance to aqueous flow during the early postoperative period until a fibrous capsule forms around the plate.(e.g., Molteno or Baerveldt implants).
Two main classifications of implants
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RESERVOIR PLACEMENT
• The scleral bed is exposed with a fornix-based conjunctival flap.
• Superior quadrant (supero temporal quadrant) is preferred.
• All plates have eyelets on the anterior edge for securing the
implant to the sclera with a non-absorbable (suture#6-0 Mersilene ).
• The plate should be positioned posterior to the insertion of the rectus muscles; 8–10 mm is measured with calipers from the limbus to the central plate edge.
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TUBE ENTRY.
The tube is trimmed so that there is a bevel facing anteriorly and 2 to 3 mm will appear within the anterior chamber .
• After scrutiny for the ideal tube entry site, a 23-gauge needle is passed through the limbus to create a tight entry site. The tube tip should not be touching either the cornea or lens.
• Tube is secured to sclera using 9-0/10-0 nylon suture.
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Some surgeons construct a scleral tunnel to cover the tube.
Usually the tube is covered with some sterile biodegradable tissue, such as donor sclera, pericardium, or dura, all of which seem to be equally efficacious.
The conjunctiva is repositioned to carefully cover the tube and overlying patch graft.
WOUND CLOSURE
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Modifications
• To avoid overfiltration and hypotony in the early postoperative period, a two-stage implantation or temporary ligation of the tube may be utilized.
• Two-stage implantation: • Tube is folded back and placed under the patch graft
or beneath an adjacent rectus muscle and can be attached to the episclera with a nylon or silk suture to facilitate identification.
• In the second stage, the tube is inserted 4–6 weeks later after a fibrous capsule (pseudocyst) has formed around the plate.
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Modifications…….
• Transient flow restriction techniques :• Aqueous flow can be limited in the early
postoperative period by internal and external occlusion techniques.
Rip-cord suture
Prolene suture ligature at tip of tube
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Complications
Excessive drainage : leakage around or down the tube if the occluding suture is loose and results in hypotony and a shallow anterior chamber.
Malposition : endothelial or lenticular touch .
Tube erosion : through the sclera and conjunctiva .
Early drainage failure : blockage of the end of the tube by vitreous, blood or iris tissue .
Late drainage failure : Excessively thick fibrous capsule.
Indian J Ophthalmol. 2011 January; 59
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Complications………….
Diplopia: mechanical involvement of the superior oblique muscle if the implant impinges on the superonasal quadrant, or to the elevated space-occupying bleb that can form over the plate, causing restriction and muscular limitation.
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NONPENETRATING GLAUMA SURGERY(NPGS)
Indications1.All open-angle glaucomas (especially if): Early surgical intervention required.Monocular patient.Large diurnal fluctuations .2.High risk of choroidal effusions or
hemorrhages. 3.High risk of postoperative hypotony. 4.Uveitic glaucoma without extensive PAS.5.Congenital glaucoma.
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NPGS
Deep Sclerectomy Viscocanalostomy
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Deep sclerectomy:
The sclera is exposed and a superficial scleralflap measuring 5 5 mm is dissected, including one-third of the scleral thickness
The superficial scleral flap is one-third of the scleral thickness and is dissected 1--1.5 mm into clear cornea.
The deep sclerectomy measures 4 4 mm and the sclera isdissected, leaving about 5% of sclera over the choroidand ciliary body.
The Schlemm’s canal is identified.The sclerocorneal dissection is prolonged anteriorly 1--1.5 mm using a ruby blade or a crescent knife, in order to remove the sclerocorneal tissue behind the anterior trabeculum and Descemet’s membrane.
When the anterior dissection is completed, thedeep scleral flap is removed by cutting anteriorly first with the diamond blade.
The inner wall of the Sclemm’s canal and the juxtacanalicular trabeculum are peeled off using fineforceps.
A collagen implant is sutured in the scleral bed.
Surv Ophthalmol 53 (6) November--December 2008
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After excision of the deep tissue containing a portion of Schlemm’s canal, the remainder of Schlemm’s canal can be accessed by insertinga fine-tipped cannula into the exposed ostia of Schlemm’s canal.
Injection of viscoelastic material into Schlemm’s .
Repeated 6-7 times.
Injection of viscoelastic beneath the superficial scleral flap.
Suture the superficial scleral flap tightly.
Viscocanalostomy
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Advantages Disadvantages
No sudden decompression of anterior chamber
Suprachoroidal hemorrhage less likely
Serous choroidal detachment less likely
Reduced risk of prolonged hypotony
Less likely to get filtering bleb
Less chance of bleb leak – early or late
Less chance of blebitis, endophthalmitis
Contact lens wear less likely to be problematic
Bleb dysthesia rareLess intraocular
inflammationLess chance of intraocular
bleedingMore rapid visual
rehabilitation postoperatively
Technically more difficult.Takes longer in the operating
roomRequires some specialized
instrumentation.About 10% have actual
perforation into anterior chamber requiring iridectomy.
Intraocular pressure less likely to be lowered sufficiently in advanced glaucoma.
Pressure lowering may not last as long
It is important to remember that these procedures are in evolution and refinements are necessary.
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Complications of deep sclerectomy
Conversion to trabeculectomy because of penetration through trabecular meshwork.
Scleral ectasia.Iris incarceration, prolapse or peripheral
anterior synechiae.Descemet’s detachment.Hypotony.Hyphema.Serous choroidal detachment.Vitreous hemorrhage.Late anterior chamber bleeding during
gonioscopy.
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Contraindications:
1.Trabecular meshwork obstructed:• Extensive synicheal angle closure.• Neovascular glaucoma.• Occludable angle.
2.Altered anatomy:• Thin sclera.• Significant limbal scarring.
3. Post laser trabeculoplasty.
4.Angle recession glaucoma.
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I. The Ex-Press mini glaucoma shunt
II.Nonpenetrating Ab Externo Schlemm’s Canaloplasty
III. Ab Interno Devices: The Trabectome and Micro-bypass Stent
IV.The Gold Microshunt: A Suprachoroidal Device
Recent advances in glaucoma surgeries
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The Ex-Press mini glaucoma shunt
Originally developed to be implanted subconjunctivally through the limbusRedesigned - trabeculectomy style scleral flap.
Long term success – yet to be established.
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Canaloplasty
Nonpenetrating Ab Externo Schlemm’s Canaloplasty
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A superficial parabolic flap of approximately 250- to 300-2m thickness, 4.5 _ 4.5 mm, is made.
Deeper scleral flap is created with slightly smaller dimensions than that of the superficial flap.
Schlemm’s canal is exposed with a crescent blade
the trabeculodescemet window (TDW) can be seen.
Once the entire circumference of the canal has been cannulated with the iScience microcatheter, the device is primed with ophthalmic viscosurgical device, which can be seen emerging from the tip of the device on the right.
A 10–0 Prolene suture is tied around the end of the deviceprior to its retraction.
Once the suture has been delivered and cut away from the microcatheter, the two cut ends must be matched and tied together.
• The superficial scleral flap is then placed back into position and sutured interrupted 10–0 nylon sutures.
• High viscosity sodium hyaluronate is then injected under the superficial scleral flap using the viscocanalostomy cannula in order to maintain the scleral lake – the space where aqueous humor that has percolated through the TDW accumulates and is then absorbed into episcleral, scleral, and choroidal circulation.
• The conjunctiva is then closed with a 10–0 Vicryl suture.
Techniques in Ophthalmology 5(3):102–106, 2007
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Advantages: Drawbacks:
• Absence of vision-threatening
complications such as:
• Choroidal detachments,
• Shallow or collapsed anterior chambers, and
• Prolonged hypotensive
periods.
Descemet’s tear.
Elevated postoperative pressure
( possible inflammatory changes in the canalicular structures).
Difficult procedure, which needs an experienced deep sclerectomy or viscocanalostomy surgeon.
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Shunts into
schlemm’s canal
The Trabecto
me
Micro- bypass Stent
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Ab Interno Devices: The Trabectome and Micro- bypass Stent
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Trans Am Ophthalmol Soc v.104; Dec 2006
Microelectrocautery handpiece designed to ablate trabecular meshwork and Schlemm’s canal inner wall tissue over an area of several clock hours..The device is a disposable handpiece that is activated by foot pedal control connected to a console that allows the surgeon to adjust infusion, aspiration, and dissipated electrosurgical energy.
• A clear corneal near-limbal 1.6-mm keratome incision is made. Viscoelastic may or may not be necessary to allow safe insertion of the instrument tip to allow infusion flow and anterior chamber stability.
• Surgical tip is advanced under gonioscopic control to engage nasal meshwork before activating aspiration and ablation by progressively depressing the foot pedal and rotating the tip parallel to the iris just anterior to the scleral spur.
• Ablation with continual infusion and aspiration is performed along an arc of 30 ° to 60°.
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Two functions: 1. providing direct access of aqueous into the schlemm’s from the anterior chamber (the snorkel effect) and 2. pushing the anterior trabecular meshwork away from the posterior wall of Schlemm’s canal.
Click icon to add picture
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The Gold Microshunt: A Suprachoroidal Device
Click icon to add picture
Arch Ophthalmol. 2009;127(3):264-269.
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Postoperative clinical image of a patient after Gold Micro Shunt implantation. Note the good position of the shunt in the anterior chamber (A), with no shunt-corneal or shunt-iris touching, as seen in the gonioscopic view (B).
Arch Ophthalmol. 2009;127(3):264-269.
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Endoscopic Cyclophotocoagulation:
Indications:•In cases of refractory glaucoma•Patients on maximum medical therapy showing continued progression of disease were often considered as appropriate candidates.•Patients who had failed filtration surgery or were considered at high risk for failure or complications post-traditional filtration procedures.
•Better visualization of the tissue being treated •Less destructive method of applying the laser,
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ECP employs - 810-nm diode laser,
allows the surgeon to precisely
aim and deploy the laser to cause
effective cycloablation while
avoiding damage to adjacent
structures.
Extensive contraction of the ciliary processes was observed as well as changes to the ciliary body epithelium.
There was much less destruction (if any) to the ciliary body muscle
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Procedures of historical importance:
Cyclodialysis was once a mainstay in the management of aphakic glaucoma. Its principle was to mechanically disrupt the iris root at its scleral spur attachment so that a cleft was created between the anterior chamber and suprachoroidal space.
Significant hemorrhage was almost unavoidable, as was hypotony resulting from an overfunctioning cleft, which if spontaneously healed would lead to a precipitous rise in IOP.
Other common complications included cataract and stripping of Descemet’s membrane. With so many more physiologic options for surgical control of the IOP, this procedure is now of historical relevance only.
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References1.Becker-Shaffer's Diagnosis and Therapy of the Glaucomas, 8e
Robert L. Stamper MD , Marc F. Lieberman MD , Michael V. Drake MD
2. Shields Textbook of Glaucoma (Allingham, Shields' Textbook of Glaucoma) Karim F. Damji , Sharon Freedman , Sayoko E. Moroi (Editor), M. Bruce Shields.
3. Kanski's Clinical Opthalmology: A Systematic Approach 6th Ed .Mohd Zafrullan Zamberi Ophthalmology.
4. Oxford American Handbook of Ophthalmology. James C. Tsai, MD, MBA.
5. The glaucomas: concepts and fundamentals.Tarek M. Eid ,George L. Spaeth.
6. The Glaucoma Book A Practical, Evidence-Based Approach to Patient Care Editors
Paul N. Schacknow , John R. Samples
7. Yanoff & Duker: Ophthalmology, 3rd
8. The role of artificial drainage devices in glaucoma surgery(Indian Journal of Ophtahlmology.)1998(46):1,41-46.R Thomas, A Braganza, G Chandrasekhar, S Honavar, AK Mandal, R Ramakrishnan, BS Rao, R Sihota, NN Sood, B Shantha, L Vijaya .Christian Medical College, Vellore, Chennai, India.
9. Nonpenetrating Glaucoma Surgery.Efstratios Mendrinos, Andre´ Mermoud, and Tarek Shaarawy, Surv Ophthalmol 53:592--630, 2008.