Surgical Managment Flashcards
Surgery of the AC angle and iris
Laser trabeculoplasty -ALT -ALT laser iridotomy LPI Laser pupilloplasty Iris sphincterotomy Incisional iridectomy Trabeculotomy Cnaaloplasty Cyclodialyss
Laser trabeculoplasty
- laser treatment targeting TM
- reduces IOP by improving the facility of outflow
- can have IOP spikes post op (within 24 hour). Treat with A2 agonist 1 hour before and immediately after procedure to reduce risk. Eyes with higher pretreatment IOPs tend to have a greater decrease in IOP, except if IOP was greater than 30mmHg
- common comoplcaitions: iritis, peripheral anterior synechiae
Types of laser trabeculoplasty
Argon laser trabeculoplasty (ALT)
Selective laser trabeculoplasty (SLT)
Argon laser trabeculoplasty (ALT)
- treat 180 degrees first treatment
- causes scarring-cannot repeat treatment in same area
- IOP reduction: 6-9hhMhg; may occur weeks later
- most successfully in POAG, XF, pigmentary glaucoma
Selective laser trabeculoplasty (SLT)
- targets pigment TM cells (melanin) without causing structural damage to nonpigemtned cells
- IOP reduction: 3-18mmHg; may occur weeks later
- 64.4% success rare of 4.4mmHg pressure drop in 180 degree treatment
Laser iridotomy
- creates a hole in peripheral iris with an argon or Nd:YAG laser
- creates equalization of pressure between posterior and anterior chambers, deepens AC, opens AC chamber angle
- procedure of choice for angle closure glaucoma
- Abraham contact lens is helpful to: keep lids separated, minimizes corneal epitheliual burns by acting as a heat sink, provides some control of eye movement
- complications: transient IOP spike, mild anterior uveitis, hyphema, corneal damage, cataract, retinal burn, monocular blurring, closure of iridotomy (first few weeks, argon, from accumulation of pigment granules and debris)
Laser peripheral iridoplasty (gonioplasty or peripheral iris retraction)
-Argonne laser to create contraction burns or peripheral iris-opening up angle. Tightening of the peripheral iris, pulls it posteriorly from TM
Indications of laser peripheral iridoplasty (gonioplasty or peripheral iris retraction)
Patent iridotomy fails (possible in microophthalmic or nanophthlamic eye), swelling or forward rotation of CB (plateau iris syndrome) or presence of peripheral anterior synechiae
Complications of laser pioperhal iridoplasty (gonioplasty or peripheral iris retraction)
IOP elevation, mild transient iritis
Laser pupilloplasty
Partially dilates pupil by applying contraction burns near the pupillary portion of the iris
Indications of laser pupilloplasty
Alternative method for pupillary block when laser iridotomy not possible (cloudy cornea); pupillary block glaucoma in aphakia or pseudophakia
Complications of laser pupilloplasty
IOP rise, transient iritis
Iris sphinctoerotomy
Pupil is enlarged, reshaped, or repositioned by making a linear cut across the iris with an argon laser, allowing the intrinsic tension of the iris to spread the cut apart
Incisional iridectomy
A procedure in which a small section of peripheral iris is excised through limbal incision
Studies show: incision vs laser have similar efficacy and safety
Incision vs laser iridectomy
Have similar efficacy and safety
Acute angle closure and incisional iridectomy
Filtering surgery more likely required after laser than incisional
Complications of incisional iridectomy
Hemes from iris or CB if accidentally cut, incomplete iridectomy (cutting only stroma, leaving pigment epithelium intact), injury to the lens, endophthalmitis
Trabeculotomy
- create an eopning in the TM to establish a direct communication between the AC and schlemms canal
- laser or incisional techniques
Complications of trabeculotomy
If schlemms canal is not properly identified, a false passage may be created into either the AC or the supraciliary space: create of a cyclodialysis and possible hyphema
Trabectome
Probe is inserted through TM and into schlemms canal: thermal ablation is used to remove TM and internal wall of schlemms canal for 60-140 degrees
Canaloplasty
-utilizes a microcatheter or tube placed in the schlemms canal to enlarge the drainage canal, relieving pressure inside the eye
Indications of canaloplasty
Open angle glaucoma, especially patients at high rusk for infection or bleeding; patients who have had complications in the other eye from trabeculectomy; patients who wear contact lenses may also be good candidates for this procedure
Cyclodialysis
Separation of the ciliary body from the scleral spur (using a cyclodialysis spatula): creates direct communication between AC and suprachoroidal space
What does cyclodialysis do
Increases uveoscleral outflow and reduces aqueous production (from changing ciliary body anatomy)
Indications of cyclodialysis
Alternative to filtering surgery, especially in aphakic eye or in combination with cataract extraction
Complications of cyclodialysis
Heme, damage to descemets membrane, corneal damage, tearing ciliary body or iris, lens injury, vitreous loss
MOA of drainage fistula
Creation of an opening/fistula at the limbus which allwosa for direct communication between AC and subconjunctival space
- fistula bypasses TM, schlemms canal, and collecting channels
- aqueous is absorbed by surrounding subconjunctival space or crosses conjunctival epithelium and drains with tears through the NLD
MOA of filtering Bleb
Elevation of conjunctiva at the surgical site
- blebs with good IOP control are associated with decreases vascualrity with numberou microcysts in the epithelium and are low and diffuse or more circumscribed and elevated
- functioning blebs have loosely arranges tissue with histological clear spaces
- failed blebs have Dense collagenous CT
- aqueous filters through conjunctiva and mixes with tear film or is absorbed by vascular or perivascualr conjunctival tissue
Basic technique: corneal traction suture
Rectus suture OR corneal suture; to move eye during surgery
Basic technique: limbal stab incision (paracentesis site)
Self healing incision into the AC at the limbus (usually temporally at the horisztonal meridian or IT quadrant) to inject fluid at the end of the procedure
Basic technique: preparation of the conjunctival flap
- critical step: most common cause for failure is scarring of the filtering bled
- flap at 12 o’clock (wider limbus in this area) or one of the superior quadrants
- limbus-based vs fornix-based flap: similar success rates
- to minimize fibroblasts/scarring: preserve tenon capsule by dissecting dessecting between capsule and episcerla when preparing the flap
Basic technique: mitomycin C
An antimetabolite used during the initial stages of a treabeculectomy to prevent excessive post op scarring and thus reduce the risk of failure
Basic technique: viscoelastic agents
- Na hyaluronate, healon
- injected into AC to reduce risk of hypotony, suprachoroidal effusion, minimize intraoperative bleeding
- complications: iris prolapse during surgery, higher early post op IOP
Basic technique: PI
- some surgeons perform and others do not, based on specific surgery
- may occur after fistula created or after, based on specific surgery
Basic technique: closure of conjunctival flap
- suture to close wound
- leaking wound may lead to a persistent flat bleb to anteiror chamber or both
Most critical step in incisional glaucoma surgery
Conjunctival flap
-higher rate of bleb failure if scarring
Post op managment of glaucoma surgery
- topical mydriatic-cycloplegics 2-3 weeks to maintain AC depth
- topical antibiotic 7-10 days
- topical steroids to reduce conjunctival scarring 4-6 weeks. Associated with higher trabeculectomy success rates. Some prefer los does topical steroid indefinitely
Complications of glaucoma surgery
Elevated IOPs and flat AC
-delayed suprachoroidal heme (few days post op, pain, nausea, reduced vision)
Elevated IOP and deep AC
- failing bleb: typically low to flat; heavily vascualriaed with no microcysts
- TX: topical steroids q1-2 hours, lyse scleral flap sutures, digital pressure (apply steady pressure with index finger to inferior sclera through lower lid for 15s)
Other early post op complications
Uveitis
Hyphema
Dellen (local causer like depression in the peripheral cornea)
Loss of central vision
Ocular decompression retinopathy (intraretinal heme immediately after trabeculectomies)
Late post op complications
- late failure of filtration
- leaking filtering bleb (always do Seidel test at exam)
- bleb related infections (blebitis, endopthalmitis)
- cataracts
- overhanging filtering bleb) large bleb may gradually extend down over the cornea, treat iwth argon laser to bled or incisional surgery to lift bleb)
- spontaneous hyphema
- hypotony and ciliochorifal detachment
- corneal changes )reduced endothelial cell count)
- eyelid changes
- sympathetic ophthalmia
Indications of drainage device surgery
- failed trabeculectomy
- young patients: 1 month-13 years old for childhood glaucoma
- NVG
- uveitis glaucoma
- severe conjunctival scarring and previous ocualr surgery
- aniridia
Drainage devices for glaucoma
- device is implanted in the eye, extending from AC to subconjunctival space
- design: silicone tube that extends from AC to a plate/disc/encircling element beneath conjunctiva and tenon capsule. Devices with open tubes are likely to habe early post op hypotony, so requires temporary closure with ligament or stent
- elevated IOPs in first few weeks/months after implantation due to fibrous capsule formation around the implant plate=hypertensive phase. Filtering bleb may fail due to increases thickness of fibrous capsule
Open tube drainage devices
- baerveldt implant: non valves; typically under rectus muscel in ST quadrant
- Molteno implant
- schocket tube shunt: silicone tube is extended from AC to a 360 degree encircling silicone band
Flow restrictive drainage devices
Valve mechanism to decrease hypotony
- Ahmed glaucoma valve
- Krupin implants
Complications of drainage devices
Hypotony
- early post op Tx-injection of dense viscoelastic into AC
- late post op Tx- permanently occlude tube
Elevated IOP Migration, extrusion, erosion of tube Endopthalmitis Visual loss Corneal compensation and graft failure Diplopia and ocualr motility disturbance
