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CPT code 66170: Trabeculectomy, without prior scarring2026 Medicare rate & RVUs

Reports an ab externo trabeculectomy to lower intraocular pressure by creating a guarded drainage pathway, without scarring from prior ocular surgery or trauma.

CMS RVU26DEffective Oct 1, 2026109 payment localities7.2K Medicare services in 2024

Medicare pays $938.23 for 66170 nationally in a facility.

Medicare rate · 66170

Trabeculectomy, without prior scarring

Office or facility?

Work RVUs
13.59
Total RVUs
28.09
Global days
090

National rate · 2026

$938.23

Facility setting, before claim adjustments.

See every locality for 66170 →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.

Your location

Medicare pays by the payment locality where the service is performed.

On this page 10 sections
  1. Medicare rate
  2. What 66170 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 66170 covers

An ophthalmic surgeon performs this filtering operation to lower intraocular pressure, commonly for glaucoma that remains inadequately controlled with medication or laser treatment. The surgeon creates a guarded opening through the sclera so aqueous fluid can drain beneath the conjunctiva and form a filtering bleb. This code describes the procedure without scarring from previous ocular surgery or trauma; the presence of such scarring distinguishes the related 66172 service. The procedure is typically performed in an operating room, and the operative report should identify the eye, surgical approach, and relevant prior ocular history.

Report the service for the eye treated. CMS 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 other procedures are subject to the standard 50% multiple-procedure reduction. For bilateral surgery, modifier 50 is paid at 150%. Assistant-at-surgery payment may be made; co-surgeon payment requires 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 66170 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

66170 office and facility rates by payment locality
Payment localityOfficeFacility
AlabamaUnavailable$866.44
AlaskaUnavailable$1,177.96
ArizonaUnavailable$919.10
ArkansasUnavailable$857.42
Atlanta, GAUnavailable$954.08
Austin, TXUnavailable$960.97
Bakersfield, CAUnavailable$975.62
Baltimore area, MDUnavailable$986.82
Beaumont, TXUnavailable$895.33
Brazoria, TXUnavailable$929.82

66170 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
66170 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 66170 rate is calculated

Each of 66170’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 · 66170

RVUs × geographic indexes × conversion factor

Office or facility?

Work13.59

13.59 RVUs× 1.000 GPCI

Practice expense13.41

13.41 RVUs× 1.000 GPCI

Malpractice1.09

1.09 RVUs× 1.000 GPCI

Adjusted RVUs

28.0900

Conversion factor

$33.4009

Medicare rate

$938.23

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

Payment rules and modifiers for 66170

66170 has a 90-day global period: related visits in that window are included in the surgery payment.

CMS payment indicators · 66170

Trabeculectomy, without prior scarring

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 · 66170

Trabeculectomy, without prior scarring

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

66170 without 50 · national facility

$938.23

Trabeculectomy, without prior scarring

66170-50 · Bilateral: 150%

$1,407.35

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

66170 compared with similar codes

Compare codes · National

4 codes, side by side

Office or facility?

  • 66170

    Trabeculectomy, without prior scarring13.59 wRVU

    Not priced

  • 66172

    Glaucoma surgery, prior surgery or trauma scarring14.47 wRVU

    Not priced

  • 66174

    Canaloplasty, without retained stent7.43 wRVU

    Not priced

  • 66180

    Glaucoma shunt, with graft14.63 wRVU

    Not priced

How to choose

66172Glaucoma surgeryPrior surgery or trauma scarring
Choose 66170 for trabeculectomy without the specified prior-surgery or trauma scarring; 66172 is the corresponding service when that scarring is present.
66174CanaloplastyWithout retained stent
66174 describes transluminal dilation of the aqueous outflow canal without a retention device. It is a different approach from creating a trabeculectomy filtration pathway.
66180Glaucoma shuntWith graft
66180 involves aqueous shunt surgery with a graft. 66170 is a trabeculectomy rather than implantation of that shunt.

Codes related to 66170

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

Codes related to 66170
CodeHow it relatesNational office range
Same family
66172Glaucoma surgery, prior surgery or trauma scarringTrabeculectomy distinguished by scarring from prior ocular surgery or trauma.No office rate
Used instead
66150Glaucoma surgery, trephination with iridectomyTrabeculotomy is a different glaucoma operation for lowering intraocular pressure.No office rate
66174Canaloplasty, without retained stentCanal dilation uses a transluminal approach without a retention device.No office rate
66175Canal dilation, with retained stentCanal dilation with a retention device differs from trabeculectomy.No office rate
66180Glaucoma shunt, with graftAqueous shunt surgery uses an implanted drainage pathway with a graft.No office rate

66170 billing questions

When should 66172 be considered instead?

Use 66172 when scarring from previous ocular surgery or trauma is present. The operative documentation should support which condition applies.

How is bilateral trabeculectomy reported?

For bilateral surgery, report modifier 50; CMS pays this code at 150%.

Does the global period include postoperative visits?

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

How does the multiple-procedure reduction work?

When other procedures are performed in the same session, the highest-valued procedure is paid in full and the others are paid at 50%.

Can an assistant or co-surgeon be reported?

Assistant-at-surgery payment may be made. Co-surgeon payment requires supporting documentation; team surgery is not permitted.

What should the operative note establish?

Document the eye treated, the ab externo filtering procedure performed, and whether scarring from prior ocular surgery or trauma is present.

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 66170PPRRVU2026_Oct_nonQPP.csv, line 7,366 (RVU26D)

Open CMS sourceHow we calculate rates

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