Minimallt invasive Glaucoma Surgery

1. Dr. Aditi Singh
Minimally invasive glaucoma surgery
(MIGS)

2. Definition: ( FDA )
 IOP-lowering surgery with the following
characteristics that distinguish it from traditional
glaucoma surgery:
• ‘Minimally traumatic’
• Via an ab-interno conjunctiva-preserving
approach
• High safety profile
• Rapid recovery
• Frequently combined with cataract extraction
• Provides more modest IOP lowering thanCurr Opin Ophthalmol 2012, 23:96–104

3.  Offer more modest results than traditional
glaucoma surgery, but with the benefit of a safer
risk profile.
 These procedures are currently targeted at
patients with mild-to-moderate glaucoma.
 MIGS procedures - indicated for patients with
glaucoma less severe than that requiring
traditional incisional surgery
 MIGS procedures by definition should
preserve the conjunctiva from surgical

4. Types :
 Bypass trabecular meshwork resistance to
aqueous flow with stents into Schlemm’s canal
(iStent, Hydrus).
 Via drainage into the suprachoroidal space
(Cypass, iStent Supra) .
 By excision of TM itself (Trabectome) .
 Endo-cylodiode uses directly observed ablation of
ciliary processes under endoscopic control .

5. i Stent

7. iStent Trabecular Micro-Bypass
Stent (Glaukos)
1 mm x 0.33 mm
Snorkel: 0.25 mm x 120 µm (bore diameter)
Weight: 60 µg
Surgical grade nonferromagnetic titanium
Heparin-coated to promote self-priming and facilitate outflow
iStent® is FDA approved in the U.S., C.E. marked in the E.U., and has Medical Device Approval in Canada
Self-Trephining Tip
Snorkel
0.3 mm
Lumen 120 µm
1 mm x 0.33 mm
Snorkel: 0.25 mm x 120 µm (bore
diameter)
Weight: 60 µg
Surgical grade nonferromagnetic
titanium
Heparin-coated to promote self-
priming and facilitate outflow

8. iStent: Indication
 In conjunction with
cataract surgery
 Mild to moderate open-
angle glaucoma
 Currently treated with
ocular hypotensive
medication

9. iStent: Mechanism
 Designed to improve
aqueous outflow thru
the natural
physiologic pathway
 Creates a bypass
through trabecular
meshwork to
Schlemm’s canal

10. iStent

12. What's in the Pipeline?

13. Ophthalmology. 2011 Mar;118(3):459-67.
At 12 months:
68% of iStent subjects
with IOP ≤ 21 mm Hg
without medication vs.
50% with cataract
surgery alone (p=0.004)
0
20
40
60
80
100
Cataract Surgery iStent
Percent of Eyes With IOP ≤ 21 mm Hg Without Medication Use

14. Ophthalmology. 2011 Mar;118(3):459-67.
At 12 months:
15% of iStent with phaco vs.
35% phaco only group on
medication (p=0.001)
0
50
100
CataractSurgery iStent
PercentofPatientsonOcularHypotensive Medication

16. Mechanism & complications :
 The stent dilates Schlemm canal by approximately 166 mm
along the length of device .
 It is implanted through a clear corneal incision under direct
gonioscopic view.
 It creates a maximum SC dilation of 241 mm or
approximately 4-5 times the natural cross-sectional area of
SC.
 Dilates Schlemm’s canal for approximately three clock hours
in the nasal quadrant, thereby enhancing aqueous outflow.
 Reported complications included two cases of iris damage
and three cases of mild hyphema that resolved within a

17. Surgical technique
manual inserter
through the TM into SC
1 mm inlet of the microstent
remains outside SC
Canal
dilatation
TM bypass,

20. Studies :
 HYDRUS I study :Preliminary1year results - meanIOP
lowering of 20% in patients treated with the Microstent
alone, with a concurrent 69% reduction in use of
glaucoma medications.
 HYDRUS II study: Compared phacoemulsification
alone and phacoemulsification combined with
Microstent . At the two-year follow up period, 73
percent of the treatment group were medication
free compared with 38 percent of the control
group (p value 0.0008)
 HYDRUS III : Compares phacoemulsification
combined with either the Hydrus or the first-
generation iStent.
 HYDRUS IV : is a FoodandDrugAdministration–
approved trial that is currently on going in the United

21. Ophthalmology Volume 122, Number 7, July 2015

22. CyPass :
 CyPass suprachoroidal shunt (Transcend Medical,
Menlo Park, Calif.)
 Implanted from an ab interno approach under
gonioscopic view.
 Conjunctival and scleral dissection is avoided.

23.  The CyPass is 6.35mm long and has a single lumen of
about 300 mm.
 Made of polyimide and designed to be both
biocompatible and non biodegradable.
 Aqueous can enter the distal lumen residing in the
anterior chamber , and pass into the suprachoroidal
space through
multiple fenestrations along the length of the implant.
 Optical coherence tomography has been used to
confirm device placement in the supra- choroidal
space with a surrounding fluid pocket.

24.  Early results have shown that implantation of the
stent at the time of cataract surgery or as a stand
alone procedure leads to a significant decrease in
IOP and/or glaucoma medi- cation use.
 Obstruction and encapsulation are possible
sources of failure.

26. The Trabectome:

27. 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° to ensure complete
viscoelastic removal thereafter.

29. Review of 115 Trabectome patients vs. 102 trab-
MMC patients.
Success rates (IOP<21 mmHg or >20% reduction) at
2 years:
22.4% for trabectome and 76.1% for trab (P=0.001)
Ophthalmology. 2012 Jan;119(1):36-42.

30. Trabectome had 100% hyphema POD #1, plus 4.3%
other complications, compared to 35.3%
complication rate
for trabeculectomy (P=.001) .
Ophthalmology. 2012 Jan;119(1):36-42.

31. Side Effects and Complications :
 Descemet’s injury
 Ciliary body injury
 Reflux bleeding, hyphema
 Zonule injury

32. Excimer Laser Trabeculotomy.
 Energy of a xenon chloride pulsed excimer laser
connected to a quartz fiber optic probe.
 The procedure intends to enhance outflow facility by
creating microperforations in the TM and inner wall
of SC.
 The probe tip is beveled at 65 degrees to aid the
placement against the angle via gonioscopic or
endoscopic guidance .
 Eight to ten laser punctures are spaced over 90
degrees, each pulse
delivering a mean energy of 1.2mJ over 80 ns
duration.

34. EndoscopicCyclophotocoagulation:
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,

35. 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

36. The ICE Procedure
Cataract Extraction
ECPiStent

37. What is ICE?
16.5% IOP
lowering at 3 years
Mansberger. Ophthal. 2012;
119:1826-31.
33% IOP
lowering with
cataract
extraction
Samuelson. Ophthal.
2011;118:459-67.
43% IOP lowering with cataract extraction
Kahook; J Glaucoma. 2007;16:527-30.

38. Mechanisms of ICE?
? Angle widening
? Decreased
aqueous
production
Increased
trabecular
outdlow
Decreased aqueous production