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Billing code 66174: CanaloplastyMedicare rate & RVUs

Reports internal dilation of the eye’s aqueous drainage canal for glaucoma when the surgeon leaves no stent or other device in place.

CMS RVU26DEffective Oct 1, 2026109 payment localities37.3K Medicare services in 2024

Medicare pays $540.43 for 66174 nationally in a facility.

Medicare rate · 66174

Canaloplasty

Swap in your local Medicare rate.

Work RVUs
7.43
Total RVUs
16.18
Global days
090

National rate · 2026

$540.43

Facility setting, before claim adjustments.

See every locality for 66174 → · 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 66174 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 66174 covers

An ophthalmologist reaches the drainage angle from inside the eye and enlarges Schlemm canal to improve aqueous outflow, leaving no implant or stent behind. The procedure is used to lower intraocular pressure in glaucoma and is typically performed in an operating room with gonioscopic visualization by an ophthalmologist, often one with glaucoma surgical expertise.

Report 66174 when the canal is dilated without a retained device; use 66175 when a device or stent remains. The operative report should identify the treated eye, the canal-dilation work, and whether an implant was left in place. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. In a same-session multiple-procedure claim, the highest-valued procedure is paid in full and other procedures at 50%. Modifier 50 bilateral payment is 150%. An assistant at surgery may be paid; co-surgeons require supporting documentation, and team surgery is 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 66174 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

66174 office and facility rates by payment locality
Payment localityOfficeFacility
AlabamaUnavailable$497.91
Alaska*Unavailable$673.55
ArizonaUnavailable$529.18
ArkansasUnavailable$492.55
AtlantaUnavailable$549.43
AustinUnavailable$554.54
BakersfieldUnavailable$563.76
Baltimore/Surr. CntysUnavailable$568.91
BeaumontUnavailable$514.49
BrazoriaUnavailable$535.69

66174 rates by state

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

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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
66174 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 66174 rate is calculated

Each of 66174’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 · 66174

RVUs × geographic indexes × conversion factor

Swap in your local Medicare rate.

Work 7.43Practice expense 8.17Malpractice 0.58

16.1800 adjusted RVUs×$33.4009 conversion factor=$540.43

All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.

Payment rules and modifiers for 66174

66174 has a 90-day global period: related visits in that window are included in the surgery payment.

CMS payment indicators · 66174

Canaloplasty

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)1Permitted with supporting documentation.
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 · 66174

Canaloplasty

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.

  • 24 Unrelated E/M visit by the same physician
  • 79 Unrelated procedure (starts its own global period)
  • 58 Staged, more extensive, or therapy procedure that was planned
  • 78 Unplanned 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

66174 without 50 · national facility

$540.43

Canaloplasty

66174-50 · Bilateral: 150%

$810.64

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

66174 compared with similar codes

Compare codes

66174 vs 66175 vs 66179 vs 66183 vs 66170: national Medicare rates

Swap in your local Medicare rate.

  • 66174
    Canaloplasty · 7.43 wRVU
    —
  • 66175
    Canal dilation · 9.11 wRVU
    —
  • 66179
    Glaucoma shunt · 13.65 wRVU
    —
  • 66183
    Drainage device · 12.87 wRVU
    —
  • 66170
    Trabeculectomy · 13.59 wRVU
    —

How to choose

66175Canal dilation
Both describe internal canal-based glaucoma surgery. Choose 66174 when no device or stent is retained and 66175 when one remains.
66179Glaucoma shunt
66179 describes aqueous shunt surgery without a graft; 66174 dilates the eye’s drainage canal without leaving a device or stent.
66183Drainage device
66183 is for insertion of an anterior-segment drainage device. 66174 is canal dilation without a retained device or stent.
66170Trabeculectomy
66170 represents filtering surgery, while 66174 uses an internal canal-based approach to improve aqueous outflow.

Codes related to 66174

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

Codes related to 66174
CodeHow it relatesNational office range
Same family
66175Canal dilationCanal-based sibling code for dilation when a device or stent is retained.No office rate
Used instead
66179Glaucoma shuntAqueous shunt surgery is a different outflow procedure.No office rate
66180Glaucoma shuntAqueous shunt surgery with a graft is a different outflow procedure.No office rate
66183Drainage deviceDrainage-device insertion is a distinct surgical approach to glaucoma.No office rate
66170TrabeculectomyFiltering surgery is a different operative approach for glaucoma.No office rate
Often billed with
66984Cataract surgeryCataract extraction may be performed during the same session.No office rate

66174 billing questions

How does 66174 differ from 66175?

Use 66174 when the canal is dilated and no device or stent is left in the eye. Use 66175 when a device or stent remains.

Can 66174 be reported with cataract surgery?

It may be performed in the same session as cataract extraction when both services are carried out and documented. CMS applies its same-session multiple-procedure payment reduction.

What documentation supports 66174?

The operative report should describe the internal approach, the canal-dilation work, the eye treated, and whether any device or stent was retained.

How is bilateral 66174 reported?

CMS lists this as a bilateral procedure paid at 150% with modifier 50. The documentation should support treatment of both eyes.

What postoperative care is included?

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

May an assistant or co-surgeon be paid?

An assistant at surgery may be paid. Co-surgeons are paid only with supporting documentation; team surgery is not permitted.

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 66174PPRRVU2026_Oct_nonQPP.csv, line 7,368 (RVU26D)

Open CMS sourceHow we calculate rates

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