CPT code 65850: Trabeculotomy, external approach2026 Medicare rate & RVUs in Maine
Reports glaucoma surgery that opens the trabecular drainage pathway through an external approach to improve aqueous outflow from the eye.
CMS doesn’t publish an office rate for 65850 in Maine.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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What 65850 covers
An ophthalmologist performs an ab externo trabeculotomy by approaching the drainage angle from outside the eye and opening the trabecular meshwork to improve aqueous humor outflow. The procedure is used for glaucoma, including congenital or developmental glaucoma, and is performed in a surgical setting. It differs from an internal angle incision because the surgeon reaches the trabecular meshwork through an external approach.
Report 65850 when the operative documentation supports this external approach and the trabecular incision. Record the treated eye and any other procedures performed during the session. Medicare assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. For multiple procedures in one session, the highest-valued procedure is paid in full and other procedures are paid at 50%. Bilateral reporting with modifier 50 is paid at 150%. Assistant-at-surgery payment is restricted; 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 65850 pays more and less in Maine
| Payment locality | Office | Facility |
|---|---|---|
| Rest of Maine | Unavailable | $677.91 |
| Southern Maine, ME | Unavailable | $700.44 |
How the 65850 rate is calculated
Each of 65850’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 · 65850
RVUs × geographic indexes × conversion factor
Work11.11
11.11 RVUs× 1.000 GPCI
Practice expense9.39
9.39 RVUs× 1.000 GPCI
Malpractice0.88
0.88 RVUs× 1.000 GPCI
Adjusted RVUs
21.3800
Conversion factor
$33.4009
Medicare rate
$714.11
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 65850
65850 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 65850
Trabeculotomy, external approach
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 1 | Not paid (statutory restriction). |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.10/0.70/0.20 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 65850
Trabeculotomy, external approach
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.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 50 · payment effect
With and without the modifier
65850 without 50 · national facility
$714.11
Trabeculotomy, external approach
65850-50 · Bilateral: 150%
$1,071.17
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).
65850 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 65820GoniotomyAngle incision
- Choose 65850 for the external approach to the trabecular meshwork; 65820 describes an internal goniotomy approach.
- 65855Laser trabeculoplastyTrabecular meshwork treatment
- 65855 is laser treatment of the trabecular drainage angle. It does not describe the external incision reported with 65850.
- 66170TrabeculectomyWithout prior scarring
- 66170 describes trabeculectomy, which creates a filtration pathway; 65850 opens the trabecular meshwork through an external approach.
65850 billing questions
How is 65850 different from goniotomy 65820?
65850 describes an external approach to the trabecular meshwork. Goniotomy 65820 approaches and incises the angle internally.
Are related postoperative visits separately reported?
The 90-day global period includes related postoperative care and the day-before preoperative visit.
How should bilateral trabeculotomy be reported?
When the procedure is performed bilaterally, report modifier 50; CMS pays the bilateral procedure at 150%.
What happens when another procedure is performed in the same session?
Under the standard multiple procedure reduction, the highest-valued procedure is paid in full and the other procedure or procedures are paid at 50%.
Can an assistant or co-surgeon be reported?
Assistant-at-surgery payment is restricted. Co-surgeons are paid only with supporting documentation, and 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
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