66180

🌊 CPT Code 66180 - Aqueous Shunt to Extraocular Equatorial Plate Reservoir, External Approach; Without Valve Mechanism

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📋 Code Description

Full Official Description: Aqueous shunt to extraocular equatorial plate reservoir, external approach; without valve mechanism

66180 describes the surgical implantation of a non-valved glaucoma drainage device (GDD) — also referred to as a tube shunt or aqueous shunt — consisting of a silicone tube connected to an extraocular equatorial plate (reservoir) that is sutured to the episclera in the equatorial region of the globe. This procedure is performed via an external (open) approach through a conjunctival peritomy and is among the most technically demanding and clinically significant procedures in glaucoma surgery.

The term “without valve mechanism” in the descriptor distinguishes this code from valved GDD implants. Non-valved devices have no internal flow restriction and require deliberate intraoperative or postoperative tube occlusion strategies to prevent early hypotony during the bleb maturation phase. The two primary non-valved devices in clinical use are:

• Baerveldt Glaucoma Implant (BGI): Single-piece silicone device available in 250 mm² and 350 mm² plate sizes; the larger surface area provides a more robust long-term filtration bleb; the most widely used non-valved GDD in the United States following the TVT (Tube vs. trabeculectomy) and ABC (Ahmed Baerveldt Comparison) trials
• Molteno Implant: The original GDD (developed by Anthony Molteno in the 1960s-70s); available in single-plate (134 mm²) and double-plate (268 mm²) configurations; the double-plate Molteno requires bicanalicular tube routing between the two plates; less commonly used today but remains viable, particularly in resource-limited settings

⚠️ Valved GDD Distinction: Devices with an integrated pressure-sensitive valve mechanism that restricts flow until IOP exceeds a set threshold — primarily the Ahmed Glaucoma Valve (AGV) models FP7, FP8, S2, B3 — are coded differently. Verify current payer and AMA guidance on the appropriate code for valved devices, as coding for Ahmed vs. Baerveldt/Molteno has evolved. Some payers historically accepted 66180 for all extraocular-plate GDDs regardless of valve mechanism; others differentiate. Always verify the device implanted and cross-reference the current CPT descriptor and payer LCD/NCD.

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🔬 Procedure Overview

The implantation of a non-valved GDD involves a multi-stage intraoperative process:

1. Anesthesia:

• Peribulbar or retrobulbar block (adult cases)
• General anesthesia (pediatric cases; congenital/juvenile glaucoma)
• Monitored Anesthesia Care (MAC) with supplemental regional block

2. Conjunctival Peritomy and Exposure:

• A limbus-based or fornix-based conjunctival peritomy in the planned quadrant (most commonly superotemporal, as this quadrant offers the most scleral surface area and best access beneath the rectus muscles)
• Blunt dissection through Tenon’s capsule to expose bare episclera
• Identification and isolation of the adjacent rectus muscles (e.g., superior and lateral recti for superotemporal placement) using muscle hooks for safe plate positioning

3. Equatorial Plate Positioning and Fixation:

• The plate is positioned 8-10 mm posterior to the surgical limbus, straddling the two adjacent rectus muscles with the anteriorly positioned wings of the plate tucked beneath the muscle bellies (Baerveldt design specifically incorporates muscle fenestrations for this purpose)
• The plate is secured to the episclera with two non-absorbable sutures (typically 9-0 or 8-0 nylon or polyester) through the fixation holes on the plate body
• Proper plate positioning is critical — too anterior risks corneal touch by the tube; too posterior risks choroidal effusion or reduced bleb formation

4. Tube Occlusion (Non-Valved — Critical Step):

• Because non-valved devices have no resistance to aqueous outflow prior to bleb encapsulation, unrestricted flow immediately post-implantation would cause severe hypotony (IOP near zero), risking choroidal effusion, suprachoroidal hemorrhage, and hypotony maculopathy
• Several occlusion strategies are used:
  • Intraluminal ligature (vicryl stitch): A 7-0 or 8-0 polyglactin suture is tied tightly around the tube to occlude flow; the absorbable suture dissolves over 4-8 weeks, gradually releasing flow as the bleb matures
  • External ligature + venting slits: Ligature occludes the tube; 1-3 small radial incisions (venting slits) proximal to the ligature allow partial flow during the healing phase
  • 3-piece staged approach (Baerveldt): Tube exteriorized and capped initially; second-stage tube insertion into anterior chamber after bleb maturation (less common today)

5. Anterior Chamber Entry and Tube Placement:

• A 23-gauge or 25-gauge needle track is created through the sclera at the limbus (approximately 0.5-1.0 mm posterior to the surgical limbus), angled to enter the anterior chamber parallel to the iris plane
• The tube is trimmed to appropriate length with a bevel-up cut, ensuring 2-3 mm of tube tip within the anterior chamber, positioned anterior to the iris and well away from the corneal endothelium
• Tube can alternatively be placed in the sulcus (ciliary sulcus) in aphakic or pseudophakic eyes, or via a pars plana approach (requires concurrent vitrectomy — see separately reportable codes)

6. Patch Graft Placement:

• A patch graft of donor preserved sclera, donor cornea, or processed pericardium (e.g., Tutoplast) is placed over the tube at the limbus to prevent tube erosion through the overlying conjunctiva — one of the most common long-term complications of tube shunts
• The patch graft is secured with absorbable or non-absorbable sutures
• This is included in 66180 and is not separately reportable

7. Conjunctival Closure:

• Tenon’s capsule and conjunctiva are closed in one or two layers using absorbable sutures
• A watertight closure is essential to prevent early bleb leak and hypotony

8. Intraoperative Anterior Vitrectomy (if required):

• If vitreous presents in the anterior chamber (aphakic or post-vitrectomy eye), an anterior vitrectomy may be required to prevent tube occlusion — this may be separately reportable (see Excludes section)

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💰 Work RVUs & Payment

Component	Value
wRVU (Facility)	14.61
wRVU (Non-Facility)	14.61
Global Period	090 (ninety days)
Assistant Payable	✅ Yes (indicator: 1)
Co-Surgery	✅ Yes (indicator: 1)
Team Surgery	❌ No (indicator: 0)
Bilateral Surgery	Rare; each eye billed separately
Multiple Procedure Indicator	2 (standard reduction applies)
Laterality Required	✅ RT or LT mandatory

wRVU Context: At 14.61 facility wRVUs, 66180 is among the highest-valued ophthalmologic surgical procedures on the Medicare Physician Fee Schedule — reflecting the technical complexity, prolonged operative time (typically 60-120+ minutes), significant risk profile, and specialized skill set required. It substantially outvalues routine cataract surgery (66984, ~11.01 wRVU) and is broadly comparable to complex anterior segment reconstructions.

90-Day Global Period: All standard postoperative care — including suture lysis, tube ligature release monitoring, bleb management, needle revision of encapsulated bleb, and IOP management visits — is bundled for 90 days postoperatively. Separately billable services within the global include unrelated E/M encounters (modifier 24), staged procedures (modifier 58), unplanned return to the OR (modifier 78), and services by a different physician (modifiers 54/55).

Assistant at Surgery: The complexity and duration of GDD implantation, combined with the need for meticulous plate positioning, muscle manipulation, and conjunctival closure, supports the use of an assistant surgeon in many cases. 66180 carries an assistant payable indicator of 1 — Medicare and most commercial payers will reimburse an assistant at ~16% of the primary surgeon’s allowable when billed with modifier 80, 81, or AS.

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👁️ Laterality — Mandatory Billing Requirement

⚠️ Laterality modifiers are REQUIRED on every claim line for 66180. Missing laterality is a top cause of claim rejection and audit vulnerability in ophthalmology. The eye modifiers below apply:

Modifier	Description	Usage with 66180
-RT	Right eye	GDD implanted in the right eye
-LT	Left eye	GDD implanted in the left eye
-50	Bilateral	Same-day bilateral implantation (exceedingly rare; each eye billed separately on two lines preferred)

Bilateral GDD: Simultaneous bilateral GDD implantation is clinically very rare but may occur in specific pediatric glaucoma scenarios (bilateral congenital/infantile glaucoma under general anesthesia). When performed bilaterally on the same date, report two separate line items: 66180-RT and 66180-LT. The second eye typically receives a 50% payment reduction under multiple procedure rules.

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✅ What’s Included (Bundled into 66180)

The following services are integral components of 66180 and are not separately reportable:

• Conjunctival peritomy and Tenon’s dissection
• Rectus muscle isolation (hook placement) for plate positioning
• Equatorial plate positioning, measurement, and scleral fixation sutures
• Intraluminal tube ligature (vicryl or similar absorbable suture occlusion)
• Venting slits (if performed as part of tube occlusion strategy)
• Anterior chamber paracentesis (if performed as part of tube placement technique)
• Sclerotomy creation for tube entry
• Tube trimming and beveling
• Anterior chamber tube insertion and positioning
• Patch graft placement over tube at limbus (donor sclera, cornea, or pericardium) — bundled regardless of graft material used
• Conjunctival and Tenon’s layer closure
• Subconjunctival antibiotic and steroid injection at closure (when performed at same operative session)
• Foley/draping and standard operative preparation
• Intraoperative IOP monitoring
• Standard postoperative monitoring within the 90-day global period including:
  • IOP checks
  • Bleb assessment
  • Tube position monitoring
  • Ligature dissolution assessment
  • Patch graft surveillance

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🚫 Excludes / Separately Reportable

Service	Separately Reportable Code	Notes
Revision of aqueous shunt (non-valved)	66184	Repositioning, tube resuturing, plate revision; non-valved device
Revision of aqueous shunt (valved)	66185	Revision of valved GDD
Trabeculectomy (no prior surgery)	66170	Different glaucoma filtering procedure — fistulization
Trabeculectomy (with prior surgery/scarring)	66172	Trabeculectomy with fibrosis/scarring
Anterior segment drainage device, no reservoir	66183	MIGS devices (standalone): iStent, Hydrus, Xen gel stent (standalone)
Pars plana tube insertion with vitrectomy	67036 + 66180	Pars plana approach requires concurrent vitrectomy; 67036 separately reportable; append 59/XU
Anterior vitrectomy required for tube placement	67005	If vitreous in AC requires removal for safe tube placement; append 59 with documentation
Cataract extraction at same session (combined procedure)	66984, 66982, 66985	Phacoemulsification + IOL implantation; commonly performed concurrently; separately reportable with modifier 51 or per payer policy
Gonioscopy at same session	92020	Anterior chamber angle evaluation; separately reportable with documentation
Corneal transplant (combined with GDD)	65730, 65750, 65755	Penetrating keratoplasty or DSAEK combined with GDD in bullous keratopathy + glaucoma
Retrobulbar/peribulbar injection of anesthetic	67500	Only if anesthesia is billed by the surgeon personally; typically billed by anesthesia provider
Suture lysis (laser) within global	Typically included	Laser suture lysis of conjunctival retention sutures is generally within global
Return to OR for tube repositioning	66184 + 78	Unplanned revision within 90-day global
Bleb needling with antimetabolite (outside global)	66250	Needling revision of encapsulated/fibrosed bleb after global period
Application of intraoperative antimetabolite (MMC)	No separate CPT	Intraoperative mitomycin-C application is bundled into 66180 — not separately reportable
Scleral patch graft material (facility charge)	Facility bills separately	Patch graft material (donor tissue/pericardium) is a facility supply charge; professional service of placing it is bundled
E/M visit same day (if separately identifiable)	Appropriate E/M + 25	Must be significant, separately documented, and beyond pre-operative assessment
Diagnostic imaging — OCT, visual fields	92134, 92083	Separately reportable with documentation; not bundled into surgical code

🔴 Combined Phacoemulsification + GDD (Triple Procedure)

A very common clinical scenario is the combined procedure of:

• 66984 (or 66982) - Phacoemulsification with IOL (cataract extraction)
• 66180 - Aqueous shunt implantation (GDD)
• Sometimes + corneal transplant (65755) for triple procedure (DSAEK + cataract + GDD)

When both 66184 and 66180 are performed at the same session:

• Report both codes with appropriate laterality modifiers
• Append modifier -51 (multiple procedures) to the lower-valued code per standard multiple procedure rules — however, CMS automatically applies multiple procedure reductions; verify payer-specific rules
• Alternatively, some payers prefer the procedures listed in descending value order with the secondary code carrying modifier -51
• Document the combined surgical indication clearly: “concurrent cataract and medically refractory glaucoma requiring surgical intervention”

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🌿 Code Tree / Family

Eye and Ocular Adnexa - Anterior Segment - Glaucoma Surgery (66150-66250)
│
├── ── TRABECULECTOMY (Filtering Surgery) ──────────────────────────────
│
├── 66150  Fistulization of sclera for glaucoma; trephination with
│              iridectomy
│
├── 66155  Fistulization of sclera for glaucoma; thermocauterization
│              with iridectomy
│
├── 66160  Fistulization of sclera for glaucoma; sclerectomy with
│              punch or scissors, with iridectomy
│
├── 66165  Fistulization of sclera for glaucoma; iridencleisis or
│              iridotasis
│
├── 66170  Fistulization of sclera for glaucoma; trabeculectomy
│              ab externo in absence of previous surgery
│              └── Standard trabeculectomy; no prior ocular surgery
│
├── 66172  Fistulization of sclera for glaucoma; trabeculectomy
│              ab externo with scarring from previous ocular surgery
│              or trauma (includes injection of antifibrotic agents)
│              └── Complex trabeculectomy; prior surgery or trauma
│
├── ── AQUEOUS SHUNT / DRAINAGE DEVICE (GDD) ───────────────────────────
│
├── 66174  Transluminal dilation of aqueous outflow canal; without
│              retention of device or stent
│              └── Canaloplasty / catheter dilation of Schlemm's canal
│
├── 66175  Transluminal dilation of aqueous outflow canal; with
│              retention of device or stent
│              └── With stent (e.g., iTrack with suture tensioning)
│
├── 66179  Aqueous shunt to extraocular equatorial plate reservoir,
│              external approach; without valve mechanism
│              └── See note: verify current AMA CPT descriptor vs. 66180
│                  distinction; may represent a variant or same-family code
│
├── 66180  ◀ YOU ARE HERE
│              Aqueous shunt to extraocular equatorial plate reservoir,
│              external approach; without valve mechanism
│              └── Non-valved GDD: Baerveldt (250mm², 350mm²),
│                  Molteno (single-plate, double-plate)
│              ├── -RT - Right eye
│              ├── -LT - Left eye
│              └── Patch graft, tube ligature: INCLUDED
│
├── 66183  Insertion of anterior segment aqueous drainage device,
│              without extraocular reservoir, external approach
│              └── Standalone MIGS: iStent inject, Hydrus, Xen Gel Stent
│                  (when NOT combined with cataract surgery)
│                  Note: MIGS with cataract → use add-on 66991/66989
│
├── ── REVISION OF AQUEOUS SHUNT ────────────────────────────────────────
│
├── 66184  Revision of aqueous shunt to extraocular equatorial plate
│              reservoir; without valve mechanism
│              └── Surgical revision of Baerveldt, Molteno (tube resuture,
│                  plate repositioning, tube occlusion, externalization)
│
├── 66185  Revision of aqueous shunt to extraocular equatorial plate
│              reservoir; with valve mechanism
│              └── Surgical revision of Ahmed, Krupin (valved GDDs)
│
├── ── OTHER GLAUCOMA PROCEDURES ────────────────────────────────────────
│
├── 66250  Revision or repair of operative wound of anterior segment,
│              any type, early or late, major or minor procedure
│              └── Bleb needling with antimetabolite; wound revision
│
├── 65820  Goniotomy
│              └── For congenital/developmental glaucoma; pediatric
│
└── 65850  Trabeculotomy ab externo
               └── Incisional approach to Schlemm's canal; pediatric
                   and some adult cases

📌 GDD Surgery Comparison Table

Device Type	Valve?	Plate Area	CPT Code	Notes
Baerveldt 250	❌ Non-valved	250 mm²	66180	Smaller plate; pseudophakic, aphakic
Baerveldt 350	❌ Non-valved	350 mm²	66180	Most common; lower long-term IOP
Molteno Single-Plate	❌ Non-valved	134 mm²	66180	Original GDD design
Molteno Double-Plate	❌ Non-valved	268 mm²	66180	Two plates connected by tube
Ahmed FP7 (silicone)	✅ Valved	184 mm²	Verify current code	Polypropylene plate; most common Ahmed
Ahmed S2 (polypropylene)	✅ Valved	184 mm²	Verify current code	Firmer plate material
Ahmed B3 (pars plana)	✅ Valved	184 mm²	Verify current code	Pars plana version
Krupin	✅ Pressure-sensitive valve	Variable	Verify current code	Largely historical

💡 Coding Clarity Note: The AMA CPT codebook language specifies “without valve mechanism” for 66180. Coders should identify the specific device implanted from the operative report and match it to the appropriate CPT code. When the device has an integrated valve (Ahmed), verify whether the current CPT edition has a distinct code or whether the payer’s LCD/coverage determination addresses valved vs. non-valved coding separately. When in doubt, query the operative surgeon and reference the current AMA CPT book and any applicable CMS LCD.

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🏥 ICD-10-CM Commonly Paired Diagnoses

🔴 Primary Open-Angle Glaucoma (POAG)

ICD-10-CM glaucoma codes require laterality AND glaucoma stage (unspecified, mild, moderate, severe, indeterminate). Always code to the maximum specificity documented.

Stage Key:

• 0 = Unspecified stage
• 1 = Mild stage
• 2 = Moderate stage
• 3 = Severe stage
• 4 = Indeterminate stage

ICD-10-CM	Description	HCC	Notes
H40.1110	Primary open-angle glaucoma, right eye, unspecified stage	❌ No HCC	Avoid unspecified when stage documented
H40.1111	Primary open-angle glaucoma, right eye, mild stage	❌ No HCC	Mild POAG, right
H40.1112	Primary open-angle glaucoma, right eye, moderate stage	❌ No HCC	Moderate POAG, right
H40.1113	Primary open-angle glaucoma, right eye, severe stage	❌ No HCC	Severe POAG — most common indication for GDD
H40.1114	Primary open-angle glaucoma, right eye, indeterminate stage	❌ No HCC	Use when staging cannot be determined
H40.1120	Primary open-angle glaucoma, left eye, unspecified stage	❌ No HCC	—
H40.1122	Primary open-angle glaucoma, left eye, moderate stage	❌ No HCC	Moderate POAG, left
H40.1123	Primary open-angle glaucoma, left eye, severe stage	❌ No HCC	Severe POAG, left — primary GDD indication
H40.1130	Primary open-angle glaucoma, bilateral, unspecified stage	❌ No HCC	Bilateral POAG; use if both eyes documented bilaterally
H40.1133	Primary open-angle glaucoma, bilateral, severe stage	❌ No HCC	Bilateral severe POAG

🔴 Low-Tension / Normal-Tension Glaucoma (NTG)

ICD-10-CM	Description	HCC	Notes
H40.1210	Low-tension glaucoma, right eye, unspecified stage	❌ No HCC	NTG — progressive despite normal IOP
H40.1212	Low-tension glaucoma, right eye, moderate stage	❌ No HCC	Moderate NTG, right
H40.1213	Low-tension glaucoma, right eye, severe stage	❌ No HCC	Severe NTG, right
H40.1223	Low-tension glaucoma, left eye, severe stage	❌ No HCC	Severe NTG, left

🔴 Pseudoexfoliative Glaucoma (Capsular Glaucoma)

ICD-10-CM	Description	HCC	Notes
H40.1410	Capsular glaucoma with pseudoexfoliation of lens, right eye, unspecified stage	❌ No HCC	PXF glaucoma — often aggressive; high GDD indication rate
H40.1412	Capsular glaucoma with pseudoexfoliation of lens, right eye, moderate stage	❌ No HCC	Moderate PXF glaucoma, right
H40.1413	Capsular glaucoma with pseudoexfoliation of lens, right eye, severe stage	❌ No HCC	Severe PXF glaucoma — high surgical rate
H40.1423	Capsular glaucoma with pseudoexfoliation of lens, left eye, severe stage	❌ No HCC	Severe PXF, left

🔴 Pigmentary Glaucoma

ICD-10-CM	Description	HCC	Notes
H40.1310	Pigmentary glaucoma, right eye, unspecified stage	❌ No HCC	Pigment dispersion syndrome with elevated IOP
H40.1313	Pigmentary glaucoma, right eye, severe stage	❌ No HCC	Severe; progressive; younger patients
H40.1323	Pigmentary glaucoma, left eye, severe stage	❌ No HCC	Severe pigmentary glaucoma, left

🔴 Primary Angle-Closure Glaucoma (PACG)

ICD-10-CM	Description	HCC	Notes
H40.2010	Unspecified primary angle-closure glaucoma, unspecified eye, unspecified stage	❌ No HCC	Use specific laterality/stage codes when documented
H40.2013	Unspecified primary angle-closure glaucoma, unspecified eye, severe stage	❌ No HCC	Severe PACG — may progress to requiring GDD
H40.2113	Acute angle-closure glaucoma, right eye, severe stage	❌ No HCC	Acute ACG — GDD may be needed if trabeculectomy not viable
H40.2213	Chronic angle-closure glaucoma, right eye, severe stage	❌ No HCC	Chronic ACG, severe; GDD often preferred over trabeculectomy
H40.2223	Chronic angle-closure glaucoma, left eye, severe stage	❌ No HCC	Chronic ACG, left, severe

🔴 Secondary Glaucoma — Trauma

ICD-10-CM	Description	HCC	Notes
H40.30X0	Glaucoma secondary to eye trauma, unspecified eye, unspecified stage	❌ No HCC	Post-traumatic glaucoma; GDD often preferred given conjunctival scarring
H40.31X3	Glaucoma secondary to eye trauma, right eye, severe stage	❌ No HCC	Severe post-traumatic glaucoma, right
H40.32X3	Glaucoma secondary to eye trauma, left eye, severe stage	❌ No HCC	Severe post-traumatic glaucoma, left

🔴 Secondary Glaucoma — Inflammation (Uveitic Glaucoma)

ICD-10-CM	Description	HCC	Notes
H40.40X0	Glaucoma secondary to eye inflammation, unspecified eye, unspecified stage	❌ No HCC	Uveitic glaucoma — GDD preferred when trabeculectomy risky due to inflammation
H40.41X3	Glaucoma secondary to eye inflammation, right eye, severe stage	❌ No HCC	Severe uveitic glaucoma, right
H40.42X3	Glaucoma secondary to eye inflammation, left eye, severe stage	❌ No HCC	Severe uveitic glaucoma, left

🔴 Secondary Glaucoma — Other Eye Disorders (Neovascular, Iridocorneal, Lens-Induced)

ICD-10-CM	Description	HCC	Notes
H40.50X0	Glaucoma secondary to other eye disorders, unspecified eye, unspecified stage	❌ No HCC	Broad category; use more specific code when available
H40.51X3	Glaucoma secondary to other eye disorders, right eye, severe stage	❌ No HCC	Neovascular glaucoma (NVG), iridocorneal endothelial syndrome (ICE), etc.
H40.52X3	Glaucoma secondary to other eye disorders, left eye, severe stage	❌ No HCC	Severe secondary glaucoma, left

💡 Neovascular Glaucoma (NVG): One of the most common and clinically challenging indications for 66180. NVG is caused by iris and angle neovascularization secondary to:

• Proliferative diabetic retinopathy (E11.3511 / E11.3512) — code the diabetic retinopathy combination code as a secondary diagnosis
• Central retinal vein occlusion (H34.11 / H34.12)
• Ocular ischemic syndrome
• In NVG, trabeculectomy has a low success rate due to aggressive fibrovascular proliferation; GDD is the preferred surgical approach after pan-retinal photocoagulation (PRP) and anti-VEGF treatment

🔴 Drug-Induced Glaucoma

ICD-10-CM	Description	HCC	Notes
H40.60X0	Glaucoma secondary to drugs, unspecified eye, unspecified stage	❌ No HCC	Steroid-induced glaucoma — common; requires adverse effect coding
H40.61X3	Glaucoma secondary to drugs, right eye, severe stage	❌ No HCC	Severe steroid glaucoma, right
H40.62X3	Glaucoma secondary to drugs, left eye, severe stage	❌ No HCC	Severe steroid glaucoma, left
T38.0X5A	Adverse effect of glucocorticoids and synthetic analogues, initial encounter	❌ No HCC	Required when coding steroid-induced glaucoma per adverse effect guidelines

🔴 Aqueous Misdirection / Malignant Glaucoma

ICD-10-CM	Description	HCC	Notes
H40.83X0	Aqueous misdirection, unspecified eye	❌ No HCC	Malignant glaucoma / ciliary block glaucoma
H40.831	Aqueous misdirection, right eye	❌ No HCC	Rare; may require GDD after failure of medical and laser management
H40.832	Aqueous misdirection, left eye	❌ No HCC	Left eye; extremely challenging surgical management

🔴 Congenital and Developmental Glaucoma (Pediatric)

ICD-10-CM	Description	HCC	Notes
Q15.0	Congenital glaucoma	❌ No HCC	Primary congenital/infantile glaucoma — GDD commonly used when goniotomy/trabeculotomy fails; surgery under general anesthesia
H40.031	Anatomical narrow angle, right eye	❌ No HCC	Pre-glaucoma narrow angle
H40.032	Anatomical narrow angle, left eye	❌ No HCC	Pre-glaucoma
H40.051	Ocular hypertension, right eye	❌ No HCC	Elevated IOP without optic nerve damage — rarely indicates GDD
H40.052	Ocular hypertension, left eye	❌ No HCC	—

🔴 Refractory Glaucoma After Prior Surgery

ICD-10-CM	Description	HCC	Notes
H40.1113	Primary open-angle glaucoma, right eye, severe stage	❌ No HCC	Most GDD cases involve failed prior therapy (medications, SLT, trabeculectomy)
Z96.89	Presence of other specified functional implants	❌ No HCC	Prior tube shunt or drainage implant documented; relevant for revision context
Z98.89	Other specified postprocedural states	❌ No HCC	History of prior glaucoma surgery (trabeculectomy, cyclophotocoagulation)
H59.311	Postprocedural bleb associated endophthalmitis, right eye	❌ No HCC	Prior bleb infection — increases GDD over repeat trabeculectomy preference
H59.312	Postprocedural bleb associated endophthalmitis, left eye	❌ No HCC	Failed bleb, left

🔴 Systemic Conditions Frequently Documented as Secondary

ICD-10-CM	Description	HCC	Notes
E11.9	Type 2 diabetes mellitus without complications	✅ HCC 19	Common comorbidity; may be cause of NVG; use combination code if ocular complication present
E11.3511	Type 2 DM with proliferative DR, right eye, with macular edema	✅ HCC 18	When NVG driven by PDR — document the underlying diabetic retinopathy
I10	Essential (primary) hypertension	❌ No HCC	Cardiovascular risk documentation
I25.10	Atherosclerotic heart disease of native coronary artery without angina	❌ No HCC	Relevant for surgical risk stratification
Z96.1	Presence of intraocular lens	❌ No HCC	Pseudophakic eye — affects tube placement (sulcus vs. AC); note affects pars plana consideration
Z89.51	Acquired absence of eye	❌ No HCC	Contralateral eye absence — documents urgency of vision preservation in operative eye

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💡 HCC Details

E11.9 / E10.9 → HCC 19 | Combination Codes E11.3x → HCC 18

Field	Detail
HCC 19	Diabetes Without Complication — RAF ~0.105
HCC 18	Diabetes with Chronic Complications — RAF ~0.302
Clinical Context	Diabetic patients are disproportionately represented in GDD surgery due to NVG from PDR and DME; when NVG is the surgical indication, the underlying diabetic retinopathy combination code (E11.3511, etc.) captures HCC 18 and documents the causal chain
Coding Guidance	Do NOT separately code E11.9 + H40.51X3 when the glaucoma is directly caused by diabetic retinopathy — the chain is: diabetes → PDR → NVG; code the combination code for the PDR and then H40.51X3 for the glaucoma secondary to the eye disorder
HCC Compounding	A patient with E11.3511 (HCC 18) + NVG + GDD surgery represents an extremely high-complexity beneficiary; ensure all diabetic complications (nephropathy E11.65, neuropathy E11.40, peripheral vascular disease E11.51) are captured for complete risk adjustment

Note on Glaucoma HCC Status:

Glaucoma itself — including severe POAG, NVG, uveitic glaucoma, and congenital glaucoma — does not currently map to an HCC category in the CMS-HCC v28 model. However, the underlying systemic causes (diabetic retinopathy, vascular occlusion) and comorbidities (diabetes, cardiovascular disease) frequently carry HCC designations that should be captured for accurate risk adjustment.

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🔧 Applicable Modifiers

Modifier	Description	Application to 66180
-RT	Right eye	✅ Required — always append for right eye GDD
-LT	Left eye	✅ Required — always append for left eye GDD
-50	Bilateral procedure	Simultaneous bilateral GDD (rare); prefer two separate lines RT + LT
-80	Assistant Surgeon	MD/DO primary assistant; common for complex GDD cases; reimbursed ~16% of primary surgeon allowable
-81	Minimum Assistant Surgeon	Limited assistant role; less common
-AS	PA/NP/CNS as Assistant at Surgery	Non-physician assistant; ~85% of assistant allowable (≈13.6% of primary)
-62	Two Surgeons	Separate surgeon for concurrent procedure (e.g., retinal surgeon performing concurrent vitrectomy + glaucoma surgeon performing GDD); each surgeon bills their respective code with 62
-22	Increased Procedural Services	Exceptional complexity: prior multiple failed glaucoma surgeries with dense conjunctival scarring, pars plana approach requiring vitrectomy, combined with penetrating keratoplasty, severe NVG with friable iris neovascularization, pediatric patient under GA with poor visualization; requires detailed operative note documentation + cover letter
-51	Multiple Procedures	When 66180 performed with cataract surgery (66984) or other concurrent ocular procedure at the same session; append to the lower-valued procedure
-52	Reduced Services	Procedure substantially less than described (e.g., plate positioned and sutured but tube not placed due to intraoperative complication); document thoroughly
-53	Discontinued Procedure	Procedure halted prior to meaningful completion due to medical emergency (e.g., suprachoroidal hemorrhage, cardiac event)
[-[54]]	Surgical Care Only	Implanting surgeon provides only intraoperative care; another provider assumes postoperative management (e.g., patient transferring care to home glaucoma specialist after out-of-town surgery)
-55	Postoperative Management Only	Receiving glaucoma specialist assumes global period care from the operating surgeon
-58	Staged Procedure	Planned related staged procedure within 90-day global (e.g., second-stage tube insertion after initial Baerveldt plate placement in a staged approach; planned corneal transplant after GDD stabilizes IOP)
-78	Unplanned Return to OR	Return for complication within global period (tube erosion through patch graft, tube malposition, choroidal effusion drainage, suprachoroidal hemorrhage evacuation)
-79	Unrelated Procedure During Global	Completely unrelated surgery within 90-day global period
-24	Unrelated E/M During Global	Office visit for condition unrelated to GDD surgery during global period; must document unrelated diagnosis
-25	Significant Separately Identifiable E/M	Same-day E/M with minor procedure; rare in this surgical context but may apply in pre-operative evaluation context
-32	Mandated Service	Workers’ comp or regulatory mandate
-47	Anesthesia by Surgeon	Surgeon personally administers anesthesia; extremely rare

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🏨 MS-DRG (Inpatient)

66180 is predominantly performed in an outpatient or ASC setting for adult patients. However, inpatient admission may occur in the following scenarios:

• Pediatric patients requiring general anesthesia for congenital/infantile/juvenile glaucoma (Q15.0) — overnight observation after GA is common
• Complex systemic comorbidities (e.g., severe cardiovascular disease, anticoagulation management, poorly controlled diabetes with NVG) requiring perioperative monitoring
• Emergency presentations — acute angle-closure glaucoma with elevated IOP refractory to medical management requiring urgent GDD
• Concurrent inpatient procedures — GDD combined with penetrating keratoplasty, vitrectomy, or silicone oil removal in a multi-procedure case
• Postoperative complications requiring inpatient monitoring (choroidal effusion, suprachoroidal hemorrhage, severe hypotony)

For inpatient admissions, the ICD-10-PCS code is reported on the UB-04.

ICD-10-PCS Equivalents

ICD-10-PCS	Description	Notes
08H13YZ	Insertion of Other Device into Right Eye, Percutaneous Approach	Right eye GDD — percutaneous (preferred for external approach)
08H23YZ	Insertion of Other Device into Left Eye, Percutaneous Approach	Left eye GDD
08HX3YZ	Insertion of Other Device into Left Conjunctiva, Percutaneous	If the dominant body part is coded to conjunctiva; facility/coder discretion
08H03YZ	Insertion of Other Device into Right Eye, External Approach	If coded as external approach; verify approach character with coder advisor

PCS Root Operation: Insertion (H) — putting in a nonbiological appliance that monitors, assists, performs, or prevents a physiological function but does not physically take the place of a body part. The GDD tube and plate system is an implanted device but does not replace the eye; therefore Insertion is the correct root operation.

PCS Approach: The external approach (X) involves procedures performed on the skin or mucous membrane directly; the percutaneous approach (3) involves entry into the body by puncture or minor incision through the skin. For GDD, which requires a conjunctival incision and scleral puncture, percutaneous (3) is most often the appropriate approach character — verify with your facility’s coding compliance guidance and applicable AHA Coding Clinic advice.

PCS Device Character: Y = Other Device (used for implanted devices not captured by a more specific device character in the eye body system table)

MS-DRG Assignment

MS-DRG	Description	Type	Typical Scenario
116	Intraocular Procedures with CC/MCC	Surgical	GDD + CC (e.g., E11.9, I10, D62) or MCC (N17.9, J96.00)
117	Intraocular Procedures without CC/MCC	Surgical	GDD implantation, no significant comorbidities
113	Orbital Procedures with CC/MCC	Surgical	If procedure grouped to orbital DRG (verify with grouper)
114	Orbital Procedures without CC/MCC	Surgical	Orbital grouping, no CCs/MCCs
124	Other Disorders of the Eye with MCC	Medical	When GDD does not drive a surgical DRG (non-OR designation)
125	Other Disorders of the Eye without MCC	Medical	Medical eye disorders without surgical DRG trigger

DRG Relative Weights (Approximate — FY2025)

MS-DRG	Relative Weight	Geometric Mean LOS
116	~1.87	~2.8 days
117	~0.98	~1.5 days
113	~1.79	~2.5 days
114	~0.92	~1.3 days

🏥 Inpatient Coder Notes — 66180 DRG Optimization:

• Verify whether the GDD ICD-10-PCS code (08H13YZ/08H23YZ) is designated as an OR procedure in your facility’s grouper — this determination drives whether the case groups to a surgical DRG (116/117) or a medical DRG (124/125). In most grouper versions, GDD implantation IS an OR procedure, grouping to DRG 116/117
• E11.3511 / E11.3512 (PDR with DME → HCC 18) function as CC in most grouper configurations — document and code underlying diabetic retinopathy when NVG is the surgical indication
• N17.9 (Acute Kidney Injury) = MCC — perioperative AKI in elderly diabetic GDD patients is not uncommon; review post-op creatinine trends; query treating physicians if AKI is documented in the chart but absent from the discharge summary
• D62 (Acute posthemorrhagic anemia) = CC — GDD procedures can involve significant bleeding, particularly in NVG with iris neovascularization; if transfusion is administered, code D62 with supporting documentation
• Pediatric patients (Q15.0 — congenital glaucoma): Pediatric DRG assignment may differ from adult; verify your grouper’s pediatric age splits and whether congenital diagnosis codes modify DRG assignment
• For combined procedures (GDD + cataract + corneal transplant), the highest-weighted procedure typically drives DRG grouping — ensure all procedures are coded in PCS to allow the grouper to assign the most appropriate DRG

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📝 Coding Examples

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🟢 Example 1 - Primary Baerveldt 350 GDD Implantation, Severe POAG, Right Eye

Clinical Scenario: A 71-year-old male with severe primary open-angle glaucoma, right eye, on maximum tolerated medical therapy (three topical agents). Selective laser trabeculoplasty (SLT) performed 18 months ago with initial response but subsequent IOP elevation. Decision made to proceed with Baerveldt 350 mm² GDD implantation, superotemporal quadrant, right eye. Intraluminal vicryl ligature placed; venting slits × 2 made proximal to ligature. Donor scleral patch graft placed over tube. Estimated blood loss minimal. No intraoperative complications.

CPT Codes:

• 66180 - RT - Aqueous shunt to extraocular equatorial plate reservoir, without valve mechanism, right eye

ICD-10-CM:

• H40.1113 - Primary open-angle glaucoma, right eye, severe stage

Inpatient UB-04 (if admitted — ICD-10-PCS):

• Principal Dx: H40.1113
• Procedure: 08H13YZ - Insertion of Other Device into Right Eye, Percutaneous Approach

MS-DRG: 117 (no CCs/MCCs) or 116 if comorbidities documented

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🟢 Example 2 - GDD for Neovascular Glaucoma Secondary to Proliferative Diabetic Retinopathy

Clinical Scenario: A 58-year-old female with Type 2 diabetes mellitus, proliferative diabetic retinopathy right eye with prior pan-retinal photocoagulation, now developing neovascular glaucoma right eye with IOP 48 mmHg despite maximum drops and recent intravitreal anti-VEGF injection. Decision made for Baerveldt 350 GDD superotemporal placement, right eye. Iris rubeosis present; careful tube placement above iris plane. Patch graft secured. Tube ligated with 7-0 vicryl.

CPT Codes:

• 66180 - RT - Non-valved aqueous shunt, right eye

ICD-10-CM:

• H40.51X3 - Glaucoma secondary to other eye disorders, right eye, severe stage (NVG = glaucoma secondary to eye disorder — iris neovascularization)
• E11.3591 - Type 2 DM with proliferative DR, right eye, without macular edema (underlying cause of NVG) ← HCC 18

Inpatient UB-04:

• Principal Dx: H40.51X3
• Secondary Dx: E11.3591 (HCC 18; functions as CC — shifts DRG toward 116)
• Procedure: 08H13YZ - Insertion of Other Device into Right Eye, Percutaneous

MS-DRG: 116 — E11.3591 functions as CC, moving case from DRG 117 → 116

💡 Coder Note: Neovascular glaucoma should never be coded as H40.1113 (POAG) — it is a secondary glaucoma driven by iris/angle neovascularization, properly coded under H40.51X3. Additionally, documenting and coding the underlying PDR (E11.3591) is critical not only for HCC capture but for establishing the causal chain and medical necessity for the GDD over less invasive procedures.

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🟢 Example 3 - Combined Phacoemulsification + Baerveldt GDD, Left Eye

Clinical Scenario: A 74-year-old male with visually significant cataract, left eye, AND severe primary open-angle glaucoma, left eye, on maximum medical therapy. Decision made for combined phacoemulsification with IOL + Baerveldt 350 GDD, left eye. Cataract removed via temporal clear cornea incision; single-piece acrylic IOL implanted in the bag. Separately, superotemporal conjunctival peritomy; Baerveldt 350 plate positioned and sutured; tube ligated; patch graft placed; conjunctiva closed. Total operative time 110 minutes.

CPT Codes:

• 66984 - LT - Phacoemulsification with posterior chamber IOL, without endoscopic cyclophotocoagulation, left eye
• 66180 - LT - 51 - Aqueous shunt to extraocular equatorial plate reservoir, without valve mechanism, left eye (lower-valued code carries modifier 51)

ICD-10-CM:

• H40.1123 - Primary open-angle glaucoma, left eye, severe stage (primary indication for GDD)
• H26.012 - Infantile and juvenile cortical, lamellar, or zonular cataract, left eye (or appropriate acquired cataract code — use H26.012 for juvenile, H25.012 for age-related nuclear, etc. per documentation)

💡 Billing Note: Both 66984 and 66180 are separately payable when performed as distinct procedures during the same operative session. The higher-valued procedure (66180, wRVU 14.61) is listed first; 66984 (wRVU ~11.01) carries modifier 51 as the secondary procedure. Under Medicare multiple procedure rules, the second procedure receives a 50% payment reduction on the professional fee. Some payers have alternative policies — verify pre-submission.

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🟢 Example 4 - Pars Plana GDD with Concurrent Vitrectomy (Complex Secondary Glaucoma)

Clinical Scenario: A 63-year-old aphakic male, vitrectomized, with silicone oil-dependent eye and refractory secondary glaucoma, left eye. Prior failed trabeculectomy. Decision: Baerveldt 350 GDD with pars plana tube insertion. Anterior vitrectomy performed first to clear vitreous strands from planned tube insertion site at pars plana (3.5 mm from limbus). GDD plate positioned, sutured; tube inserted through pars plana sclerotomy; patch graft placed; conjunctiva closed.

CPT Codes:

• 66180 - -LT - Non-valved GDD, left eye
• 67005 - -LT - -59 - Partial removal of vitreous, anterior approach (anterior vitrectomy required for safe pars plana tube placement; distinct from GDD itself; append -59 to overcome potential bundling)

ICD-10-CM:

• H40.52X3 - Glaucoma secondary to other eye disorders, left eye, severe stage
• Z96.89 - Presence of other specified functional implants (prior failed trabeculectomy/ocular implant history)
• H44.51 - Hemophthalmos, right eye (if applicable; document silicon oil status separately)

⚠️ Modifier -59 Rationale: The anterior vitrectomy (67005) is not routinely performed as part of a standard GDD implantation — it was required due to the pars plana approach in a vitrectomized aphakic eye to prevent vitreous prolapse around the tube. This represents a distinct procedural service beyond the standard GDD, justifying modifier -59 (or -XU) to override any NCCI bundling edit. Documentation in the operative report must clearly state the indication for the vitrectomy as separate from the shunt implantation.

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🟢 Example 5 - Congenital Glaucoma, Bilateral, Under General Anesthesia (Pediatric)

Clinical Scenario: A 14-month-old male with bilateral primary congenital glaucoma. IOP elevated bilaterally despite prior bilateral goniotomies. Decision made for bilateral Baerveldt 250 mm² GDD implantation under general anesthesia. Both eyes performed sequentially in the same anesthetic session. Right eye superotemporal; left eye superotemporal. Patch grafts placed bilaterally. Admitted overnight for post-GA monitoring.

CPT Codes:

• 66180 - -RT - Non-valved GDD, right eye
• 66180 - -LT - -51 - Non-valved GDD, left eye (bilateral; second eye with multiple procedure modifier; 50% reduction applies)

ICD-10-CM:

• Q15.0 - Congenital glaucoma (bilateral; single code captures bilateral congenital glaucoma)

Inpatient UB-04 (overnight admission, pediatric):

• Principal Dx: Q15.0
• Procedures:
  • 08H13YZ - Insertion of Other Device into Right Eye, Percutaneous
  • 08H23YZ - Insertion of Other Device into Left Eye, Percutaneous

MS-DRG: 116 or 117 depending on comorbidities; pediatric age may modify DRG in some grouper versions

💡 Pediatric Coding Note: Q15.0 does not carry a stage designation — the ICD-10-CM glaucoma stage codes (H40.1111, H40.1113, etc.) apply only to the acquired glaucoma categories. For congenital glaucoma, Q15.0 alone captures the condition. Use supplemental codes for specific findings if documented (e.g., H52.7 for Haab’s striae, corneal enlargement).

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🟢 Example 6 - Unplanned Return to OR for Tube Erosion Within Global Period

Clinical Scenario: Patient underwent 66180 right eye 6 weeks ago. Now presents with exposed tube through conjunctiva — patch graft melted and conjunctiva eroded over tube at limbus. Return to OR for conjunctival advancement flap repair and patch graft replacement.

CPT Codes (Return to OR):

• 66184 - -RT - -78 - Revision of aqueous shunt to extraocular equatorial plate reservoir, without valve mechanism, right eye; unplanned return to OR within global period

ICD-10-CM:

• T85.390A - Other mechanical complication of ocular prosthetic device, initial encounter (tube erosion = mechanical complication of implanted device)
• H40.1113 - Primary open-angle glaucoma, right eye, severe stage (underlying reason for original implant)

💡 Global Period Note: The 90-day global period from the original 66180 is still running. The revision (66184--78) is billed to the professional claim with modifier -78 to indicate unplanned return to the OR during the global period. CMS pays -78-modified procedures at the full surgical fee but the original global period continues to run from the original surgery date — it does not restart. A new 90-day global period would begin only if the revision was performed after the original global period expired.

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⚠️ Common Coding Pitfalls

• ❌ Do not omit -RT/-LT laterality modifiers — claim will be rejected; laterality is non-negotiable for all eye codes
• ❌ Do not use 66184 (revision) when the primary implantation is being performed — 66184 is exclusively for revision of an existing GDD; initial implantation = 66180
• ❌ Do not separately bill for the patch graft placement — it is bundled into 66180
• ❌ Do not separately bill for intraoperative MMC application — antimetabolite use during GDD surgery is not separately reportable (unlike some other ophthalmic procedures)
• ❌ Do not use 66183 (no reservoir device — MIGS) for Baerveldt or Molteno — 66183 is specifically for devices without an extraocular reservoir (iStent, Hydrus, Xen standalone); the extraocular plate is the defining feature of 66180
• ❌ Do not code glaucoma secondary to diabetic retinopathy as POAG (H40.1113) — use secondary glaucoma code H40.51X3 and separately code the underlying diabetic retinopathy combination code for accurate HCC and medical necessity documentation
• ✅ Always document the specific device name and plate size in the operative report — this supports code selection, device manufacturer documentation requirements, and audit defense
• ✅ Always document the tube occlusion strategy (vicryl ligature, venting slits) — this confirms the “without valve mechanism” descriptor and distinguishes the procedure from valved device implantation
• ✅ Always document the patch graft material (donor sclera, pericardium, cornea) and its placement — supports completeness of the procedure note and facilitates facility billing for graft material
• ✅ When combining 66180 with cataract surgery (66984), verify modifier -51 positioning — list the higher-valued code first (usually 66180 > 66984) and append -51 to the secondary code; some payers automate this but manual claim submission requires correct ordering
• ✅ For pars plana tube placement, identify whether a concurrent vitrectomy was performed — if yes, 67036 or 67005 may be separately reportable with modifier -59 or -62 (if a separate surgeon); document clearly in the operative note
• ✅ Review the glaucoma staging in the ophthalmologist’s note carefully — ICD-10-CM differentiates mild, moderate, severe, and indeterminate stages; “severe” is the most common stage justifying GDD surgery and should be coded when documented, not defaulted to “unspecified”

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📌 Quick Reference Summary

Field	Value
Code	66180
Type	CPT - Major Ophthalmic Surgery
System	Eye and Ocular Adnexa
Body Part	Anterior Chamber / Equatorial Sclera
Approach	External (open conjunctival)
Device	Non-valved extraocular plate reservoir (Baerveldt, Molteno)
Valve Mechanism	❌ Without valve
Patch Graft	✅ Included (bundled)
Tube Ligature	✅ Included (bundled)
Global Period	090 (90 days)
wRVU (Fac/Non-Fac)	14.61
Assistant Payable	✅ Yes — 80, 81, AS
Co-Surgery	✅ Yes — 62
Laterality Required	✅ Mandatory — RT or LT
Modifier 22 Eligible	✅ Yes — with extensive documentation
Modifier 51	Apply to secondary procedure in combined cases
PCS Right Eye	08H13YZ
PCS Left Eye	08H23YZ
Top Diagnoses	H40.1113, H40.1123, H40.51X3, Q15.0
HCC-Triggering DX	E11.3591 → HCC 18; E11.9 → HCC 19 (secondary)
MS-DRG (Surgical)	116 / 117 (intraocular)
MS-DRG (Medical)	124 / 125 (other eye disorders)
Revision Code	66184 (non-valved); 66185 (valved)
MIGS Alternative	66183 (no reservoir); 66991 (with cataract)

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^{AMA CPT Professional Edition 2024 · CMS Physician Fee Schedule Look-Up Tool FY2025 · CMS-HCC Risk Adjustment Model v28 · CMS NCCI Policy Manual for Medicare Services v30 · AHA Coding Clinic for ICD-10-CM/PCS FY2025 · CMS ICD-10-PCS Official Guidelines FY2025 · CMS MS-DRG Grouper v41 · CMS IPPS Final Rule FY2025 · AAO Ophthalmology Coding Resources 2024 · Gedde SJ et al. Tube versus Trabeculectomy Study (TVT) · Barton K et al. Ahmed Baerveldt Comparison Study (ABC) · CMS LCD L35036 Glaucoma Surgery}