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Billing code 66184: Shunt revisionMedicare rate & RVUs

Revision of an existing glaucoma drainage shunt without a graft, reported when the surgeon corrects a shunt problem rather than placing a new device.

CMS RVU26DEffective Oct 1, 2026109 payment localities890 Medicare services in 2024

Medicare pays $686.72 for 66184 nationally in a facility.

Medicare rate · 66184

Shunt revision

Work RVUs
9.34
Total RVUs
20.56
Global days
090

National rate · 2026

$686.72

Facility setting, before claim adjustments.

See every locality for 66184 →Billed by an NP, PA or therapist? →

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

On this page 10 sections
  1. Medicare rate
  2. What 66184 covers
  3. By payment locality
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Similar codes
  8. Related codes
  9. Billing questions
  10. Sources

What 66184 covers

An ophthalmic surgeon, often a glaucoma specialist, revises an existing aqueous shunt used to control intraocular pressure. The work may address a tube or reservoir problem, such as obstruction or malposition, to restore drainage or improve shunt function. This code distinguishes revision without a graft from revision that includes graft material, which is reported with 66185.

Select the code from the operative report’s description of the revision and whether graft material was used; do not use it for initial shunt placement. Documentation should identify the existing device, the problem addressed, the revision performed, and graft use or nonuse. Medicare assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and others at 50%. Bilateral reporting with modifier 50 is paid at 150%. An assistant at surgery may be paid; co-surgeons and team surgery are not permitted.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 66184 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

66184 office and facility rates by payment locality
Payment localityOfficeFacility
AlabamaUnavailable$632.14
Alaska*Unavailable$854.19
ArizonaUnavailable$672.27
ArkansasUnavailable$625.26
AtlantaUnavailable$698.29
AustinUnavailable$704.77
BakersfieldUnavailable$716.43
Baltimore/Surr. CntysUnavailable$723.18
BeaumontUnavailable$653.47
BrazoriaUnavailable$680.56

66184 rates by state

Office rate range in each state. Select a state to see its payment localities.

MEWIVTNHMTNDMNMINYMARIWAIDWYSDIAILINOHPANJCTORNVUTCONEMOKYWVVAMDDECAAZNMKSOKARTNNCSCDCTXLAMSALGAFLAKHI

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Local rates. Clear comparisons.

Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.

View every state and territory as a table
66184 office rate range by state
State / territoryOffice rate rangeLocalities
AKNo published base rate1
ALNo published base rate1
ARNo published base rate1
AZNo published base rate1
CANo published base rate29
CONo published base rate1
CTNo published base rate1
DCNo published base rate1
DENo published base rate1
FLNo published base rate3
GANo published base rate2
GUNo published base rate1
HINo published base rate1
IANo published base rate1
IDNo published base rate1
ILNo published base rate4
INNo published base rate1
KSNo published base rate1
KYNo published base rate1
LANo published base rate2
MANo published base rate2
MDNo published base rate3
MENo published base rate2
MINo published base rate2
MNNo published base rate1
MONo published base rate3
MSNo published base rate1
MTNo published base rate1
NCNo published base rate1
NDNo published base rate1
NENo published base rate1
NHNo published base rate1
NJNo published base rate2
NMNo published base rate1
NVNo published base rate1
NYNo published base rate5
OHNo published base rate1
OKNo published base rate1
ORNo published base rate2
PANo published base rate2
PRNo published base rate1
RINo published base rate1
SCNo published base rate1
SDNo published base rate1
TNNo published base rate1
TXNo published base rate8
UTNo published base rate1
VANo published base rate2
VINo published base rate1
VTNo published base rate1
WANo published base rate2
WINo published base rate1
WVNo published base rate1
WYNo published base rate1

How the 66184 rate is calculated

Each of 66184’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

How the rate is built · 66184

RVUs × geographic indexes × conversion factor

Work9.34

9.34 RVUs× 1.000 GPCI

Practice expense10.47

10.47 RVUs× 1.000 GPCI

Malpractice0.75

0.75 RVUs× 1.000 GPCI

Adjusted RVUs

20.5600

Conversion factor

$33.4009

Medicare rate

$686.72

Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.

Payment rules and modifiers for 66184

66184 has a 90-day global period: related visits in that window are included in the surgery payment.

CMS payment indicators · 66184

Shunt revision

RuleCMS valueWhat it means
Global period090Major surgery: the day before, the day of, and 90 days after are included.
Multiple procedures2Standard reduction: highest-valued procedure at 100%, others at 50%.
Bilateral (modifier 50)1Bilateral with modifier 50 pays 150% of the fee schedule amount.
Assistant at surgery (80/81/82/AS)2Paid.
Co-surgeons (62)0Not permitted.
Team surgery (66)0Not permitted.
Professional/technical0Physician service: no professional/technical split.
Split (54/55/56)0.10/0.70/0.20Share of the payment for pre-op, the procedure itself, and post-op care.

Global surgery period · 66184

Shunt revision

90-day global period ends

Dec 30, 2026

Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).

Visit on Oct 31, 2026

Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.

  • 24Unrelated E/M visit by the same physician
  • 79Unrelated procedure (starts its own global period)
  • 58Staged, more extensive, or therapy procedure that was planned
  • 78Unplanned return to the operating room for a related complication
SurgeryVisit
Sep 23, 2026Jan 10, 2027

Pre-op dayGlobal period

What modifiers do to the payment

Modifier 50 · payment effect

With and without the modifier

66184 without 50 · national facility

$686.72

Shunt revision

66184-50 · Bilateral: 150%

$1,030.08

Both sides on one line with modifier 50 are paid at 150% of the fee schedule amount (subject to multiple-procedure rules with other procedures).

When to use modifier 50

66184 compared with similar codes

Compare codes · National

4 codes, side by side

  • 66184

    Shunt revision9.34 wRVU

    Not priced

  • 66185

    Shunt revision10.32 wRVU

    Not priced

  • 66179

    Glaucoma shunt13.65 wRVU

    Not priced

  • 66180

    Glaucoma shunt14.63 wRVU

    Not priced

How to choose

66185Shunt revision
Use 66185 when graft material is part of the aqueous shunt revision; 66184 is the revision without a graft.
66179Glaucoma shunt
66179 represents initial aqueous shunt placement without a graft. Use 66184 when the surgeon revises an existing shunt without a graft.
66180Glaucoma shunt
66180 represents initial aqueous shunt placement with a graft; it is not the code for revising an existing shunt.

Codes related to 66184

Related codes aren’t interchangeable: bill the code that matches the service performed.

Codes related to 66184
CodeHow it relatesNational office range
Same family
66185Shunt revisionRevision of an aqueous shunt when graft material is used.No office rate
Used instead
66179Glaucoma shuntInitial aqueous shunt placement without a graft, rather than revision.No office rate
66180Glaucoma shuntInitial aqueous shunt placement with a graft, rather than revision.No office rate
66183Drainage deviceInsertion of an anterior drainage device, rather than revision of an existing shunt.No office rate

66184 billing questions

How is 66184 distinguished from 66185?

66184 is for aqueous shunt revision without a graft. Report 66185 when the revision includes a graft.

Can 66184 be reported for initial shunt placement?

No. It describes revision of an existing shunt; initial placement is represented by an insertion code such as 66179, 66180, or 66183, depending on the procedure.

What should the operative report document?

The report should identify the existing shunt, the problem being corrected, the revision performed, and whether graft material was used.

How is bilateral 66184 reported?

For bilateral surgery, report modifier 50. CMS pays the bilateral procedure at 150%.

What postoperative care is included?

The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care.

Can an assistant surgeon be reported?

Assistant-at-surgery payment may be made. CMS does not permit co-surgeons or team surgery for this code.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Show the CMS file lines behind this rate
RVUs for 66184PPRRVU2026_Oct_nonQPP.csv, line 7,373 (RVU26D)

Open CMS sourceHow we calculate rates

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