Latest Review Date:  November 2024

POLICY:

Insertion of ab externo aqueous shunts approved by the U.S. Food and Drug Administration (FDA) may be considered medically necessary as a method to reduce intraocular pressure in individuals with glaucoma where medical therapy has failed to adequately control intraocular pressure.

Use of an ab externo aqueous shunt for all other conditions, including in individuals with glaucoma when intraocular pressure is adequately controlled by medications, is considered investigational.

Insertion of ab interno aqueous stents approved by the U.S. Food and Drug Administration (FDA) as a method to reduce intraocular pressure in individuals with glaucoma where medical therapy has failed to adequately control intraocular pressure, may be considered medically necessary.

Implantation of 1 or 2 U.S. Food and Drug Administration (FDA)-approved ab interno stents in conjunction with cataract surgery, may be considered medically necessary in individuals with mild to moderate open-angle glaucoma treated with ocular hypotensive medication.

Use of ab interno stents for all other conditions is considered investigational.

POLICY GUIDELINES:

Shunts and stents are only able to reduce intraocular pressure to the mid-teens and may be inadequate when very low intraocular pressure is needed to reduce glaucoma damage.

DESCRIPTION OF PROCEDURE OR SERVICE:

Glaucoma surgery is intended to reduce intraocular pressure (IOP) when the target IOP cannot be reached using medications. Due to complications with established surgical approaches (e.g., trabeculectomy), a variety of shunts and stents are being evaluated as alternative surgical treatments for individuals with inadequately controlled glaucoma. Microstents are also being evaluated in individuals with mild-to-moderate open-angle glaucoma (OAG) currently treated with ocular hypotensive medication.

Glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide and is characterized by elevated intraocular pressure (IOP). In 2020, glaucoma affected approximately 52.7 million individuals globally, with a projected increase to 79.8 million in 2040. Glaucoma has been reported to be seven times more likely to cause blindness and 15 times more likely to cause visual impairment in Black individuals as compared to White individuals. In the U.S. in 2010, Black individuals had the highest prevalence rate of primary open angle glaucoma at 3.4% compared to 1.7% among White individuals.

In the primary (conventional) outflow pathway from the eye, aqueous humor passes through the trabecular meshwork, enters a space lined with endothelial cells (Schlemm canal), drains into collector channels, and then into the aqueous veins. Increases in resistance in the trabecular meshwork and/or the inner wall of the Schlemm canal can disrupt the balance of aqueous humor inflow and outflow, resulting in an increase in IOP and glaucoma risk.

Treatment

Ocular Medication

First line treatment typically involves pharmacologic therapy. Topical medications either increase aqueous outflow (prostaglandins, alpha adrenergic agonists, cholinergic agonists, rho kinase inhibitors) or decrease aqueous production (alpha adrenergic agonists, beta blockers, carbonic anhydrase inhibitors). Pharmacologic therapy may involve multiple medications, have potential side effects, and may be inconvenient for older adults or incapacitated individuals.

Surgery

Surgical intervention may be indicated in individuals with glaucoma when the target intraocular pressure (IOP) cannot be reached pharmacologically. Surgical procedures for glaucoma aim to reduce IOP from impaired aqueous humor drainage in the trabecular meshwork and/or Schlemm canal. Trabeculectomy (guarded filtration surgery) is the most established surgical procedure for glaucoma, which involves dissecting the conjunctiva, creating a scleral flap and scleral ostomy then suturing down the flap and closing the conjunctiva, allowing aqueous humor to directly enter the sub-conjunctival space. This procedure creates a sub-conjunctival reservoir, which can effectively reduce IOP, but commonly results in filtering “blebs” on the eye, and is associated with numerous complications (e.g., hemorrhage, scarring, hypotony, infection, leaks or bleb-related endophthalmitis) and long-term failure. Other surgical procedures (not addressed in this policy) include trabecular laser ablation, deep sclerectomy, (which removes the outer wall of the Schlemm canal and excises deep sclera and peripheral cornea), and viscocanalostomy, (which removes and dilates the Schlemm canal without penetrating the trabecular meshwork or anterior chamber). Canaloplasty involves dilation and tension of the Schlemm canal with a suture loop between the inner wall of the canal and the trabecular meshwork. This ab externo procedure uses the iTrack™ illuminated micro-catheter (iScience Interventional) to access and dilate the entire length of the Schlemm canal and to pass the suture loop through the canal.

Insertion of shunts from outside the eye (ab externo) is another surgical option to lower IOP. Examples of ab externo devices cleared by the U.S. Food and Drug Administration (FDA) include the Ahmed, Baerveldt, Molteno, and EX-PRESS mini-shunt, which shunt aqueous humor between the anterior chamber and the supra-choroidal space. These devices differ by explant surface areas, shape, plate thickness, presence or absence of a valve, and details of surgical installation. Generally, the risk of hypotony (low pressure) is reduced with aqueous shunts compared with trabeculectomy, but IOP outcomes are worse than after standard guarded filtration surgery. The risk of postoperative infection is lower with shunts than with trabeculectomy, and failure rates are similar (»10% of devices fail annually). The primary indication for aqueous shunts is for failed medical or surgical therapy, although some ophthalmologists have advocated their use as a primary surgical intervention, particularly for selected conditions such as congenital glaucoma, trauma, chemical burn, or pemphigoid.

Minimally Invasive Glaucoma Surgeries

Minimally invasive glaucoma surgeries (MIGS) are alternative, less invasive techniques that are being developed and evaluated. MIGS which use microscopic-sized equipment and smaller incisions, involves less surgical manipulation of the sclera and the conjunctiva compared with other surgical techniques. There are several categories of MIGS: miniaturized trabeculectomy, trabecular bypass, milder laser photocoagulation, and totally internal or suprachoroidal stents. Shunts and stents can be administered through an external flap of the conjunctiva and sclera (ab externo) or in a small incision in the cornea with the devices inserted through the anterior chamber of the eye (ab interno). Some ab interno micro stents may be inserted with injectors. 

Examples of ab interno devices either approved or given marketing clearance by U.S. Food and Drug Administration (FDA) include the iStent®, which is a one mm long stent inserted into the end of the Schlemm canal through the cornea and anterior chamber, iStent inject®, iStent infinite® and XEN® gelatin stent.

Because aqueous humor outflow is pressure dependent, the pressure in the reservoir and venous system are critical for reaching the target intraocular pressure (IOP). Therefore, some devices may be unable to reduce IOP below the pressure of the distal outflow system used, (e.g., < 15 mm Hg) and are not indicated for individuals for whom very low IOP is desired (e.g., those with advanced glaucoma). It has been proposed that stents such as the iStent®, iStent inject®, and Hydrus® Microstent may be useful to lower IOP in individuals with early-stage glaucoma to reduce the burden of medications and problems with compliance. One area of investigation are individuals with glaucoma who require cataract surgery. An advantage of ab interno stents is that they may be inserted into the same incision and at the same time as cataract surgery. In addition, most devices do not preclude subsequent trabeculectomy if needed. It is possible to insert more than one stent to achieve the desired IOP.

KEY POINTS:

The most recent literature review was updated through  September 25, 2024.

Summary of Evidence

For individuals who have refractory open-angle glaucoma (OAG) who receive ab externo aqueous shunts, the evidence includes randomized controlled trials (RCTs), retrospective studies, and systematic reviews. Relevant outcomes are a change in disease status, functional outcomes, medication use, and treatment-related morbidity. RCTs assessing U.S. Food and Drug Administration (FDA)-approved shunts have shown the use of large externally placed shunts reduces intraocular pressure (IOP) to slightly less than standard filtering surgery (trabeculectomy). Reported shunt success rates show that these devices are non-inferior to trabeculectomy in the long-term. The FDA-approved shunts have different adverse event profiles and avoid some of the most problematic complications of trabeculectomy. Two trials have compared the Ahmed and Baerveldt shunts. Both found that eyes treated with the Baerveldt shunt had slightly lower average IOP at five years than eyes treated with the Ahmed but the Baerveldt also had a higher rate of serious hypotony-related complications. The evidence is sufficient to determine that the technology results in an improvement in the net health outcome.

For individuals who have refractory OAG who receive ab interno aqueous stents, the evidence includes systematic reviews, a randomized controlled trial (RCT), nonrandomized comparative studies and single-arm study. Relevant outcomes are a change in disease status, functional outcomes, medication use, and treatment-related morbidity. The RCT found XEN45 to be noninferior to trabeculectomy.  The nonrandomized comparative studies reported that individuals receiving the stent experienced similar reductions in intraocular pressure (IOP) and medication use as individuals undergoing trabeculectomy. The single-arm study, with 12-month follow-up results, consistently showed that individuals receiving the stents experienced reductions in IOP and medication use reductions as seen with ab externo shunts.  Clearance for the stent was based on a review in which the FDA concluded that while there were technical differences between the stent and predicate devices (shunts), the differences did not affect safety and effectiveness in lowering IOP and medication use. The evidence is sufficient to determine that the technology results in an improvement in the net health outcome.

For individuals who have mild-to-moderate OAG who are undergoing cataract surgery who receive aqueous microstents, the evidence includes RCTs and meta-analyses of RCTs. Relevant outcomes are a change in disease status, functional outcomes, medication use, and treatment-related morbidity. Implantation of one or two microstents has received FDA approval for use in conjunction with cataract surgery for reduction of IOP in adults with mild-to-moderate OAG currently treated with ocular hypotensive medication. When compared to cataract surgery alone, the studies showed modest but statistically significant decreases in IOP and medication use through the first two years when stents were implanted in conjunction with cataract surgery. A decrease in topical medication application is an important outcome for individuals and reduces the problem of non-compliance that can affect visual outcomes. The evidence is sufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with mild-to-moderate OAG who are not undergoing cataract surgery who receive aqueous microstents as a stand-alone procedure, the evidence includes a nonrandomized trial, RCTs and a systematic review of three heterogeneous RCTs. Relevant outcomes are a change in disease status, functional outcomes, medication use, and treatment-related morbidity. Several RCTs have evaluated the use of multiple microstents, but comparators differed. Two RCTs indicate that implantation of a microstent can reduce IOP at a level similar to ocular medications at 12 month follow-up. Reduction in medications is an important outcome for individuals with glaucoma. Whether microstents remain patent after 12 months is uncertain, and whether additional stents can subsequently be safely implanted is unknown. Some evidence on longer-term outcomes is provided by an RCT that compared implantation of a single iStent® to implantation of multiple iStents. At longer-term (42 month) follow-up, the need for additional medication increased in eyes implanted with a single microstent but not with multiple microstents. The durability of multiple iStents is unknown. A fourth RCT compared implantation of the Hydrus® Microstent to two iStents. Outcomes from the Hydrus® Microstent were significantly better than two iStents, both statistically and clinically, for all outcome measures. The primary limitation of this study is that the duration of follow-up in the publication is limited to 12 months. Longer-term follow-up from this study is continuing and will answer important questions on the durability of the procedure. Corroboration in an independent study and comparison with a medical therapy control group would also increase confidence in the results. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Practice Guidelines and Position Statements

American Academy of Ophthalmology (AAO)

The American Academy of Ophthalmology (AAO, 2008) published a technology assessment on commercially available aqueous shunts, including the Ahmed, Baerveldt, Krupin, and Molteno devices, which was last reviewed for currency in 2014. The assessment indicated that, in general, IOP would settle at higher levels (approximately 18 mm Hg) with shunts than after standard trabeculectomy (14 to 16 mm Hg). Five-year success rates of 50% have been found for the two procedures, indicating that aqueous shunts are comparable with trabeculectomy for IOP control and duration of benefit (based on Level I evidence; well-designed randomized controlled trials). The assessment indicated that although aqueous shunts have been generally reserved for intractable glaucoma when prior medical or surgical therapy has failed, indications for shunts have broadened (based on Level III evidence; case series, case reports, and poor-quality case-control or cohort studies). The AAO concluded that, based on Level I evidence, aqueous shunts offer a valuable alternative to standard filtering surgery or to cyclodestructive therapy for many individuals with refractory glaucoma.

In 2020, the AAO updated its preferred practice pattern on primary open-angle glaucoma (POAG). The document notes that aqueous shunts have traditionally been used to manage medically uncontrolled glaucoma when trabeculectomy has failed to control IOP or is deemed unlikely to succeed; however, the indications for using aqueous shunts have been broadening, and these devices are being increasingly used in the surgical management of glaucoma. The preferred practice pattern notes that "several studies have compared aqueous shunts with trabeculectomy" and that the "selection of aqueous shunts or trabeculectomy should be left to the discretion of the treating ophthalmologist, in consultation with the individual patient."

American Glaucoma Society

In 2020, the American Glaucoma Society published a position paper on micro invasive glaucoma surgery. The Society supports efforts that facilitate patient access to these procedures, including more flexible regulatory pathways for new devices, expansion of the indications for already approved devices, and greater availability of information obtained by regulatory authorities.

National Institute for Health and Care Excellence

The National Institute for Health and Care Excellence (2017) updated guidance on trabecular stent by-pass microsurgery for open-angle glaucoma (OAG). The guidance stated that “Current evidence on trabecular stent bypass microsurgery for open-angle glaucoma raises no major safety concerns. Evidence of efficacy is adequate in quality and quantity.

The National Institute for Health and Care Excellence (2018) published a guidance entitled "Micro invasive Sub-conjunctival Insertion of a Trans-scleral Gelatin Stent for POAG". The guidance states that evidence is limited in quantity and quality and therefore, the procedure should only be used with special arrangements and that individuals should be informed of the uncertainty of the procedure.

U.S. Preventative Services Task Force Recommendations

Not applicable.

KEY WORDS:

Eyepass, Hydrus® Microstent, iStent®, trabecular shunt, Trabectome, Solx gold shunt®, SOLX® Gold Shunt, Ex-PRESS®, AquaFlow™, Ahmed™, Baerveldt®, Krupin, Molteno®, iStent supra, Cy Pass®, aqueous shunt, trabecular stent, micro-stent, iStent® Trabecular Micro-Bypass Stent, XEN® Gel stent, XEN® ab interno, ab externo, XEN injector, Hydrus, iStent inject®, iStent infinite®, Beacon Aqueous Microshunt

APPROVED BY GOVERNING BODIES:

The regulatory status of the various aqueous shunts and micro stents is summarized in the table below.

The first-generation Ahmed™ (New World Medical), Baerveldt® (Advanced Medial Optics), Krupin (Eagle Vision), and Molteno® (Molteno Ophthalmic) ab externo aqueous shunts were cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process between 1989 and 1993; modified Ahmed and Molteno devices were most recently cleared in 2006. Their indication for use is “in individuals with intractable glaucoma to reduce intraocular pressure where medical and conventional surgical treatments have failed.” The AquaFlow™ Collagen Glaucoma Drainage Device (STARR Surgical) was approved by FDA through the premarket approval process for the maintenance of the subscleral space following non-penetrating deep sclerectomy. In 2003, the ab externo EX-PRESS® Mini Glaucoma Shunt was cleared for marketing by FDA through the 510(k) process.

In 2016, the Xen® Glaucoma Treatment System (Allergan), which consists of the XEN45 Gel Stent preloaded into the XEN Injector, was cleared for marketing by FDA through the 510(k) process as an ab interno aqueous stent for management of refractory glaucoma. The approval was for individuals with refractory glaucoma who failed previous surgical treatment or for individuals with primary open-angle glaucoma unresponsive to maximum tolerated medical therapy. The FDA determined that this device was substantially equivalent to existing devices, specifically the Ahmed™ Glaucoma Valve and the EX-PRESS® Glaucoma Filtration Device.

In 2018, the first micro stent, the iStent® Trabecular Micro-Bypass Stent preloaded into the iStent® inject device (Glaukos) was approved by FDA through the 515(d) process for use in conjunction with cataract surgery for the reduction of IOP in adults with mild-to-moderate open-angle glaucoma currently treated with ocular hypotensive medication. In 2022, iStent infinite® was FDA-approved for primary OAG when medical and surgical treatment failed. Notably, this device is not required to be performed in conjunction with cataract surgery and contains 3 stents preloaded into an injector system.

In August 2018, Alcon announced an immediate voluntary recall of the CyPass micro stent, which had been approved by the FDA in 2016 for use in conjunction with cataract surgery in adults with mild to moderate open angle glaucoma (OAG). The recall was based on five-year post-surgery data from the COMPASS- XT long-term safety study. Results showed a statistically significant increase in endothelial cell loss among individuals receiving the CyPass micro stent compared with individuals receiving cataract surgery alone.

In September 2023, a randomized controlled trial (NCT01881425) reported two-year follow-up outcomes comparing the PRESERFLO MicroShunt (Santen) to trabeculectomy in individuals with mild to severe primary OAG inadequately controlled by maximum tolerated medical therapy. As of October 2024, FDA approval of the device is still pending.

Table 1. Regulatory Status of Aqueous Shunts and Stents

Device	Manufacturer	Type	FDA Status	Date
AquaFlow™	STAAR Surgical	Drainage device	PMA	2001
Ahmed ™	New World Medical	Aqueous glaucoma shunt; ab externo	510(k)	<1993
Baerveldt®	Advanced Medical Optics	Aqueous glaucoma shunt; ab externo	510(k)	<1993
Krupin	Eagle Vision	Aqueous glaucoma shunt; ab externo	510(K)	<1993
Molteno®	Molento Ophthalmic	Aqueous glaucoma shunt; ab externo	510(k)	<1993
EX-PRESS®	Alcon	Mini-glaucoma shunt; ab externo	510(k)	2003
XEN® Gel Stent; XEN injector	AqueSys/Allergan	Aqueous glaucoma stent, ab interno	510(k)	2016
iStent®; iStent inject®	Glaukos	Micro sent, ab interno	515(d) in conjunction with cataract surgery	2018
iStent supra®	Glaukos	Suprachoroidal stent	Not Approved; in clinical trial
CyPass®	Alcon	Suprachoroidal stent, ab interno	Company voluntarily recalled	2018
Hydrus® Microstent	Ivantis	Micro stent, ab interno	PMA approval, in conjunction with cataract surgery	2018
Beacon Aqueous Microshunt	MicroOptx	Micro-Shunt, ab externo	Not approved; in clinical trial
PRESERFLO™ Microshunt (previously InFocus)	Santan	Micro-Shunt, ab externo	Not approved; in clinical trial
iStent Infinite®	Glaukos	Micro stent, ab interno	510(k)	2022

FDA: Food and Drug Administration; PMA: premarket approval.

BENEFIT APPLICATION:

Coverage is subject to member’s specific benefits. Group-specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply

FEP contracts: Special benefit consideration may apply.  Refer to member’s benefit plan.

CURRENT CODING:

CPT Codes:

66183	Insertion of anterior segment aqueous drainage device, without extraocular reservoir, external approach
66989	Complex extracapsular cataract removal with insertion of intraocular lens prosthesis requiring devices or techniques not generally used in routine cataract surgery or performed on individuals in the amblyogenic developmental stage; including drainage device insertion, one or more
66991	Extracapsular cataract removal with insertion of intraocular lens prosthesis with drainage device insertion, one or more
0253T	Insertion of anterior segment aqueous drainage device, without extraocular reservoir; internal approach, into the suprachoroidal space
0449T	Insertion of aqueous drainage device, without extraocular reservoir, internal approach, into the sub-conjunctival space; initial device
0450T	each additional device
0474T	Insertion of anterior segment aqueous drainage device, with creation of intraocular reservoir, internal approach, into the supraciliary space
0671T	Insertion of anterior segment aqueous drainage device into the trabecular meshwork, without external reservoir, and without concomitant cataract removal, one or more

HCPCS Codes:

L8612

Aqueous Shunt

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50. Myers JS, Masood I, Hornbeak DM, et al. Prospective evaluation of two iStent((R)) Trabecular Stents, one iStent Supra((R)) Suprachoroidal Stent, and postoperative prostaglandin in refractory glaucoma: 4-year outcomes. Adv Ther. Mar 2018; 35(3):395-407.
51. National Institute for Health and Care Excellence (NICE). Trabecular stent bypass microsurgery for open-angle glaucoma [IPG575]. 2017; www.nice.org.uk/guidance/ipg575.
52. National Institute for Health and Care Excellence. Micro invasive subconjunctival insertion of a trans-sceral gelatin stent for primary open-angle glaucoma. [IPG612]. 2018; www.nice.org.uk/guidance/ipg612/chapter/1-Recommendations.
53. Netland PA, Sarkisian SR, Jr., Moster MR, et al. Randomized, prospective, comparative trial of EX-PRESS glaucoma filtration device versus trabeculectomy (XVT study). Am J Ophthalmol. Feb 2014; 157(2):433-440 e433.
54. Neuhann TH, Hornbeak DM, Neuhann RT et al. Long-term effectiveness and safety of trabecular microbypass stent implantation with cataract surgery in patients with glaucoma or ocular hypertension: Five-year outcomes.. J Cataract Refract Surg, 2019 Mar 11; 45(3).
55. Omatsu S, Hirooka K, Nitta E, Ukegawa K. Changes in corneal endothelial cells after trabeculectomy and EX-PRESS shunt: 2-year follow-up. BMC Ophthalmol. Sep 10 2018; 18(1):243.
56. Otarola F, Virgili G, Shah A, et al. Ab interno trabecular bypass surgery with Schlemms canal micro stent (Hydrus) for open angle glaucoma. Cochrane Database Syst Rev. Mar 09 2020.
57. Ozal SA, Kaplaner O, Basar BB, et al. An innovation in glaucoma surgery: XEN45 gel stent implantation. Arq Bras Oftalmol. Nov-Dec 2017; 80(6):382-385.
58. Pahlitzsch M, Klamann MK, Pahlitzsch ML et al. Is there a change in the quality of life comparing the micro-invasive glaucoma surgery (MIGS) and the filtration technique trabeculectomy in glaucoma patients?. Graefes Arch. Clin. Exp. Ophthalmol., 2016 Nov 17;255(2)
59. Paletta Guedes RA, Gravina DM, Paletta Guedes VM, Chaoubah A. Standalone Implantation of 2-3 Trabecular Micro-Bypass Stents (iStent inject ± iStent) as an Alternative to Trabeculectomy for Moderate-to-Severe Glaucoma. Ophthalmol Ther. 2022 Feb;11(1):271-292. 
60. Panarelli JF, Moster MR, Garcia-Feijoo J, et al. Ab-Externo MicroShunt versus Trabeculectomy in Primary Open-AngleGlaucoma: Two-Year Results from a Randomized, Multicenter Study. Ophthalmology. Mar 2024; 131(3): 266-276.
61. Park J, Rittiphairoj T, Wang X, et al. Device-modified trabeculectomy for glaucoma. Cochrane Database Syst Rev. Mar 13 2023; 3(3): CD010472.
62. Perez-Torregrosa VT, Olate-Perez A, Cerda-Ibanez M, et al. Combined phacoemulsification and XEN45 surgery from a temporal approach and 2 incisions. Arch Soc Esp Oftalmol. Sep 2016; 91(9):415-421.
63. Pfeiffer N, Garcia-Feijoo J, Martinez-de-la-Casa JM, et al. A Randomized Trial of a Schlemm’s Canal Micro stent with Phacoemulsification for Reducing Intraocular Pressure in Open-Angle Glaucoma. Ophthalmology. Jul 2015; 122(7):1283-1293.
64. Prum BE Jr, Rosenberg LF, Gedde SJ, Mansberger SL, Stein JD, Moroi SE, Herndon LW Jr, Lim MC, Williams RD. Primary Open-Angle Glaucoma Preferred Practice Pattern(®) Guidelines. Ophthalmology. 2016 Jan; 123(1):P41-P111.
65. Ramdas WD, Pals J, Rothova A, et al. Efficacy of glaucoma drainage devices in uveitic glaucoma and a meta-analysis of the literature. Graefes Arch. Clin. Exp. Ophthalmol., 2018 Oct 13; 257(1).
66. Salimi A, Kassem R, Santhakumaran S, et al. Three-Year Outcomes of a Schlemm Canal Microstent (Hydrus Microstent) with Concomitant Phacoemulsification in Open-Angle Glaucoma. Ophthalmol Glaucoma. 2023; 6(2): 137-146.
67. Salimi A, Watt H, Harasymowycz P. Three-Year Outcomes of Second-generation Trabecular Micro-bypass Stents (iStent inject) With Phacoemulsification in Various Glaucoma Subtypes and Severities. J Glaucoma. Mar 01 2021; 30(3): 266-275.
68. Samuelson TW, Chang DF, Marquis R, et al. A Schlemm Canal Micro stent for Intraocular Pressure Reduction in Primary Open-Angle Glaucoma and Cataract: The HORIZON Study. Ophthalmology. Jan 2019; 126(1): 29-37.
69. Samuelson TW, Sarkisian SR, Lubeck DM et al. Prospective, Randomized, Controlled Pivotal Trial of an Ab Interno Implanted Trabecular MicroBypass in Primary Open-Angle Glaucoma and Cataract: Two-Year Results.. Ophthalmology, 2019 Mar 19; 126(6).
70. Sarkisian SR Jr, Grover DS, Gallardo MJ, Brubaker JW, Giamporcaro JE, Hornbeak DM, Katz LJ, Navratil T; iStent infinite Study Group. Effectiveness and Safety of iStent Infinite Trabecular Micro-Bypass for Uncontrolled Glaucoma. J Glaucoma. 2023 Jan 1;32(1):9-18. 
71. Schlenker MB, Gulamhusein H, Conrad-Hengerer I, et al. Efficacy, safety, and risk factors for failure of standalone ab interno gelatin micro stent implantation versus standalone trabeculectomy. Ophthalmology. Nov 2017; 124(11):1579-1588.
72. Sheybani A, Vera V, Grover DS, et al. Gel Stent Versus Trabeculectomy: The Randomized, Multicenter, Gold-Standard Pathway Study (GPS) of Effectiveness and Safety at 12 Months. Am J Ophthalmol. Aug 2023; 252: 306-325
73. Stoner AM, Capitena Young CE, SooHoo JR, et al. A Comparison of Clinical Outcomes After XEN Gel Stent and EX-PRESS Glaucoma Drainage Device Implantation. J Glaucoma. Jun 01 2021; 30(6): 481-488. 
74. Swaminathan SS, Jammal AA, Kornmann HL, et al. Visual Field Outcomes in the Tube Versus Trabeculectomy Study. Ophthalmology. Sep 2020; 127(9): 1162-1169. 
75. Tanito M, Chihara E. Safety and effectiveness of gold glaucoma micro shunt for reducing intraocular pressure in Japanese patients with open angle glaucoma. Jpn J Ophthalmol. Sep 2017; 61(5):388-394.
76. Tokumo K, Okada N, Onoe H, et al. Ex-PRESS Implantation versus Trabeculectomy for Long-Term Maintenance in Patients with Open-Angle Glaucoma. Clin Ophthalmol. 2023; 17: 2525-2537.
77. Tseng VL, Coleman AL, Chang MY, et al. Aqueous shunts for glaucoma. Cochrane Database Syst Rev. Jul 28 2017; 7(7):CD004918.
78. Vlasov A, Kim WI. The efficacy of two trabecular bypass stents compared to one in the management of open-angle glaucoma. Mil Med. Mar 2017; 182(S1):222-225.
79. Vold S, Ahmed, II, Craven ER, et al. Two-year COMPASS trial results: supraciliary microstenting with phacoemulsification in patients with open-angle glaucoma and cataracts. Ophthalmology. Oct 2016; 123(10):2103-2112.
80. Vold SD, Voskanyan L, Tetz M, et al. Newly diagnosed primary open-angle glaucoma randomized to 2 trabecular bypass stents or prostaglandin: outcomes through 36 months. Ophthalmol Ther. Dec 2016; 5(2):161-172.
81. Wagner FM, Schuster AK, Emmerich J, et al. Efficacy and safety of XEN(R)-Implantation vs. trabeculectomy: Data of a "real-world" setting. PLoS One. 2020; 15(4): e0231614.
82. Wagschal LD, Trope GE, Jinapriya D, et al. Prospective randomized study comparing Ex- PRESS to trabeculectomy: 1-year results. J Glaucoma. Oct-Nov 2015; 24(8):624-629.
83. Wang X, Khan R, Coleman A. Device-modified trabeculectomy for glaucoma. Cochrane Database Syst Rev. Dec 01 2015; (12): CD010472.
84. Yadav KS, Sharma S. Implantable drainage devices in glaucoma: Quo vadis?. Eur J Pharm Sci, 2019 Mar 17; 133:1-7.
85. Yang X, Zhao Y, Zhong Y, et al. The efficacy of XEN gel stent implantation in glaucoma: a systematic review and meta-analysis. BMC Ophthalmol. Jul 15 2022; 22(1): 305.
86. Yook E, Vinod K, and Panarelli. Complications of micro-invasive glaucoma surgery. Curr Opin Opthalmol. 2018;29(2):147-154
87. Zhang X, Wang B, Liu R, et al. The effectiveness of AGV, Ex-PRESS, or trabeculectomy in the treatment of primary and secondary glaucoma: a systematic review and network meta-analysis. Ann Palliat Med. Jan 2022; 11(1): 321-331.

POLICY HISTORY:

Medical Policy Group, July 2008 (2)

Medical Policy Administration Committee, August 2008 Available for comment August 13-September 26, 2008

Medical Policy Group, July 2010 (1): Policy statement updated, Description, Key Points Medical Policy Administration Committee, June 2010

Available for comment June 18-August 2, 2010, Medical Policy Group, December 2010, Code update Medical Policy Panel, May 2011

Medical Policy Group, May 2011 (2): Policy change, Key Points and References updated Medical Policy Administration Committee, June 2011

Available for comment June 8 – July 25, 2011, Medial Policy Panel, September 2011

Medical Policy Group, September 2011 (2): Policy change, Key Points, References updated Medical Policy Administration Committee, October 2011

Available for comment October 19 through December 5, 2011, Medical Policy Panel, May 2012

Medical Policy Group, June 2012 (2): Name changed from Viscocanaloplasty and Canaloplasty to Aqueous Shunts for Glaucoma, Updated policy, Key words, Key Points, Approved by Governing Bodies, References to reflect name of policy

Medical Policy Group, September (2): Removed all references to iTrack Medical Policy Panel, October 2012

Medical Policy Group, October 2012 (2): Policy updated with literature search through August 2012. The Policy Statement for use of micro-stent is investigational. Title, Key Words, FDA approval, Key Points and References updated to support non-coverage statement for use of micro-stent.

Medical Policy Administration Committee, November 2012 Available of comment November 14 through December 28, 2012, Medical Policy Panel, September 2013

Medical Policy Group, October 2013 (2): Policy updated with literature search through August 2013. Added policy statement that iStent is considered covered in patient’s intolerance of medications when implanted in conjunction with cataract surgery. Description, Key Points, Approved by Governing Bodies, and References updated to reflect findings in literature search and new policy statement.

Medical Policy Administration Committee, October 2013 Available for comment October 16 through November 30, 2013

Medical Policy Group, December 2013 (1): 2014 Coding Update: added new code 66183, effective 01/01/2014; moved deleted code 0192T to Previous Coding section, effective 01/01/2014.

Medical Policy Panel September 2014

Medical Policy Group, September 2014 (1): Update to Description, Key Points and References. No Policy Statement change

Medical Policy Group, November 2014: 2015 Annual Coding update. Added code 0376T to current coding; Changed verbiage on 0191T to read ‘initial insertion’, no change to 0253T Medical Policy Panel, September 2015

Medical Policy Group, September 2015 (6): Updates to Key Points, Key Words, Approved by Governing Bodies and References; no change in policy statement.

Medical Policy Panel, March 2016

Medical Policy Group, March 2016 (6): Updates to Description, Key Points, Approved by Governing Bodies and References: no change to policy statement.

Medical Policy Group, December 2016 (6): Removed Cypass from investigational status in Description of Procedure. FDA approved July 29, 2016, Updated Key Points.

Medical Policy Group, December 2016: 2017 Annual Coding Update. Added new CPT codes 0449T and 0450T to Current Coding.

Medical Policy Group, January 2016 (6): Updates to Key Words and Approved by Governing Bodies to include the XEN glaucoma treatment system.

Medical Policy Panel, March 2017

Medical Policy Group, March 2017 (6): Updates to Description, Key Points, Coding, Practice Guidelines, Governing Bodies and References.

Medical Policy Panel, May 2018

Medical Policy Group, June 2018 (6): Updates to Description, Policy statement updated to distinguish ab interno vs ab externo, Key Points, Governing Bodies, Key words added (Ab interno, ab externo, Hydrus), L8612 added to Coding and References.

Medical Policy Panel, December 2018

Medical Policy Group, January 2019 (6) Updates to Description, Policy statement, Key Points, Practice Guidelines, Governing Bodies, Key Words (iStent inject) and References.

Medical Policy Panel, March 2019

Medical Policy Group, April 2019 (6): Updates to Description, Key Points, Practice Guidelines, Approved by Governing Bodies and References; no change to policy statement.

Medical Policy Panel, September 2019

Medical Policy Group, September 2019 (6): Updates to Description, Key Points, Practice Guidelines and References. No change to policy intent.

Medical Policy Panel, September 2020

Medical Policy Group, September 2020 (9): 2020 Updates to Description, Key Points and References. No change to policy statement.

Medical Policy Panel, September 2021

Medical Policy Group, September 2021 (9): 2021 Updates to Description, Key Points, and References. Policy statement updated to remove “not medically necessary,” no change to policy intent.

Medical Policy Group, November 2021 (9): 2021 Annual Coding Update. Moved CPT from Current coding section. Created Previous Coding section to include codes 0191T and 0376T.  Added CPT codes 0617T, 66989, and 66991 to the Current coding section.

Medical Policy Panel, September 2022

Medical Policy Group, September 2022 (9): 2022 Updates to Description, Key Points, References. Removed “For Dates of Service Prior to January 17, 2019” section from policy statement. Minor editorial refinements to policy statements; no change to policy intent.

Medical Policy Group, November 2022 (9): Updated Regulatory Bodies regarding iStent infinite FDA 510(k) status. 

Medical Policy Group, January 2023 (9): Updated References. No change to policy statement.

Medical Policy Panel, September 2023

Medical Policy Group, October 2023 (9): Update to Description, Key Points, Key Words, Benefit Application and References; no change to policy statement.

Medical Policy Panel, November 2024

Medical Policy Group, November 2024(9): Update to Key Points, Key Words, Governing Bodies, (removed previous coding section) and References; no change to policy intent.

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.