CPT® Code 92133

Quick Reference

• Code definition: Reports computerized ophthalmic diagnostic imaging (OCT) of the posterior segment with analysis specifically targeting the optic nerve head (RNFL thickness, cup-to-disc ratio, neuroretinal rim area). Covers one or both eyes under a single unit.
• Key billing rule: MUE is 1 per date of service. "Unilateral or bilateral" means one unit covers both eyes; billing two units for bilateral imaging will exceed the MUE and deny.
• Modifier essentials: Append modifier 26 when the interpreting physician does not own the OCT device; append TC when billing the equipment side only. Use LT or RT when only one eye is imaged. Do not append modifier 50; the bilateral payment adjustment explicitly does not apply (Bilateral Surgery Indicator 2).
• Documentation must-have: A signed, physician-authored interpretation and written report is required. The OCT device printout alone does not satisfy this requirement and is the leading documentation deficiency found on pre-payment review.
• Top confusion point: 92133 and 92134 are not interchangeable. 92133 captures the optic nerve (RNFL, ONH parameters); 92134 captures the retina (macular thickness maps). The clinical report content and device scan protocol must match the code billed.
• Payer alert: In hospital outpatient settings, 92133 is an APC status STV-Packaged code. The facility receives no separate payment; only the professional component (modifier 26) generates a PFS payment to the interpreting physician. Office-based practices billing globally receive full PFS reimbursement.
• TC reduction applies: Multiple Procedures Indicator 7 means the technical component of a lower-valued diagnostic ophthalmology service is subject to a special payment reduction when multiple imaging codes (e.g., 92133 and 92134) are billed on the same date by the same entity.

When to Use This Code

Primary indication is glaucoma diagnosis and structural progression monitoring. OCT of the optic nerve detects retinal nerve fiber layer thinning that frequently precedes measurable visual field loss, making it the core structural imaging tool for glaucoma suspects, ocular hypertension patients, and confirmed glaucoma at any stage. ICD-10-CM codes that support medical necessity include the full H40 glaucoma family, H40.05x (ocular hypertension), and H40.00x (preglaucoma/glaucoma suspect).

Secondary clinical indications include: optic neuritis (H46.xx), ischemic optic neuropathy (H47.011 to H47.013), papilledema (H47.10 to H47.13), optic atrophy (H47.20 to H47.29x), optic disc drusen (H47.321 to H47.329), and pseudopapilledema (H47.331 to H47.333). Any condition requiring quantitative structural assessment of the optic nerve head falls within scope.

Scope boundaries: This code covers the optic nerve head and peripapillary RNFL only. Imaging focused on macular thickness, drusen in the macula, retinal layers, or diabetic macular edema maps is reported with 92134 (retina) or 92137 (retina with OCT angiography). Anterior segment structures (cornea, anterior chamber angle, iris) use 92132. When both optic nerve and retinal protocols are run at the same visit with separate clinical indications, both 92133 and 92134 may be reported (see Billing section).

Provider and setting: Typically reported by ophthalmologists and optometrists in office, clinic, or ASC settings. In split-billing environments (hospital outpatient, independent diagnostic testing facilities), the TC and professional component separate. PC/TC Indicator 1 governs this code, confirming the split is permissible.

Code Differentiation Table

The most critical differentiator is 92133 vs. 92134: the anatomy scanned and the device protocol used must match the code. A macular OCT scan reported as 92133 is a miscoded claim regardless of the diagnosis. Auditors cross-reference the OCT printout protocol header against the billed code; a mismatch is an automatic finding.

flowchart TD
    A[Posterior segment OCT ordered] --> B{Which structure is the focus?}
    B --> C[Optic nerve head / RNFL]
    B --> D[Macula / retinal layers]
    B --> E[Both optic nerve AND retina\nseparate protocols, separate indications]
    C --> F[Bill 92133]
    D --> G{OCT-A vascular\ncomponent included?}
    G --> H[Yes] --> I[Bill 92134... wait\nno — bill 92137]
    G --> J[No] --> K[Bill 92134]
    E --> L[Bill 92133 AND 92134\nwith modifier 59 or XS\nif NCCI PTP edit triggered]

Billing & Modifier Rules

Units: One unit per date of service regardless of laterality. The AMA CPT "unilateral or bilateral" descriptor convention confirms this; the MUE of 1 enforces it at the claim level.

Modifier 26 and TC: When split billing applies, modifier 26 is appended by the interpreting physician's practice; TC is appended by the entity operating the device. Both components together equal the global payment. In HOPPS, the TC is packaged and generates no APC payment to the facility; the professional component 92133-26 is paid separately under the PFS.

Modifier LT / RT: Use when imaging is performed on only one eye to specify laterality. When both eyes are imaged, bill one unit with no laterality modifier.

Modifier 50: Do not use. Bilateral Surgery Indicator 2 explicitly states the 150% bilateral payment adjustment does not apply. Appending modifier 50 is incorrect and will cause processing errors.

Modifier 59 / XS: May be required when 92133 and 92134 are billed on the same date by the same provider to bypass an NCCI PTP edit. Modifier XS (separate structure) is the more precise sub-modifier; 59 is acceptable when XS is not supported by the payer system. Documentation must support distinct clinical indications for each code. Verify current quarterly NCCI PTP tables at CMS for active edit pairs and modifier indicators.

CPT codebook exclusions: The AMA CPT codebook explicitly states that 92133 may not be reported on the same date as 92227, 92228, 92229, or 92250. These are hard excludes, not modifier-bypassable edits.

Multiple Procedures TC reduction (Indicator 7): When 92133 and 92134 are both billed same-day, the TC of the lower-valued service receives a reduced payment under the special diagnostic ophthalmology multiple procedure rules. The professional component (modifier 26) is not subject to this reduction.

Global period: Global Days XXX; the global period concept does not apply. 92133 may be performed and billed at any interval supported by medical necessity, subject to LCD frequency limitations.

Documentation Essentials

Required elements for every claim:

• A distinct, signed physician interpretation separate from the device-generated printout
• Specific OCT findings: RNFL thickness values (global and by quadrant), cup-to-disc ratio, neuroretinal rim area, deviation map interpretation referenced against the normative database
• Comparison to prior studies when available, with notation of stability or progression
• Clinical significance of findings relative to the patient's ocular condition and diagnosis
• Laterality: which eye(s) were imaged and why (or documentation of bilateral imaging)
• ICD-10-CM diagnosis that supports the medical necessity of optic nerve structural assessment

Audit red flags specific to 92133:

• OCT printout in the chart with no separate physician narrative interpretation. This is the most common finding in pre-payment reviews. The device printout is generated by software; a physician clinical interpretation is a separate, required document.
• Diagnosis code that does not support optic nerve imaging (e.g., refractive error, routine exam code) paired with 92133. MACs require a diagnosis from the glaucoma (H40.xx) or optic nerve disorder (H46.xx to H47.xx) families.
• Frequency exceeding LCD limits without documented clinical justification. Stable glaucoma monitored more frequently than the MAC's standard interval requires explicit documentation of the clinical rationale (e.g., suspected rapid progression, recent IOP spike, change in visual field).
• Two units billed for bilateral imaging. A unit count of 2 for 92133 on a single DOS will auto-deny at MUE adjudication.
• 92133 billed when the OCT device log and report show a macular protocol was run, not an optic nerve head protocol. The device scan type must match the code.

Medical necessity: LCD criteria (manual verification at the CMS Medicare Coverage Database required for current article numbers and MAC-specific requirements) generally require a documented glaucoma, glaucoma suspect, ocular hypertension, or optic nerve disorder diagnosis. Ordering 92133 as a reflexive add-on without a supporting diagnosis in the record creates both a coverage and compliance risk.

Medicare, Commercial & Medicaid Payer Rules

Medicare

92133 is covered under Medicare as a diagnostic test (PC/TC Indicator 1, Type of Service 1, BETOS T2D). Payment is made under the PFS; CY2025 and CY2026 RVU values should be verified at the CMS Physician Fee Schedule Search Tool (cms.gov/medicare/physician-fee-schedule/search) for the applicable year and place of service.

MACs have published LCDs governing coverage of posterior segment OCT. LCD documentation requirements, covered diagnoses, and frequency limitations vary by MAC jurisdiction. Coders should identify the applicable MAC for the practice location and review the current LCD at the CMS Medicare Coverage Database (cms.gov/medicare-coverage-database). Common LCD provisions include: coverage for glaucoma, glaucoma suspects, and optic nerve disorders; frequency caps of 2 to 4 studies per year for stable glaucoma (more frequent with documented clinical justification); and a signed interpretation requirement.

In HOPPS, 92133 carries APC status STV-Packaged. The facility does not receive a separate APC payment; the service is packaged into the associated procedure's APC. Physician interpretation (92133-26) continues to receive PFS payment.

Commercial Payers

Most commercial payers follow Medicare coverage logic for 92133 as a medically necessary diagnostic test for glaucoma and optic nerve disease. Prior authorization is not universally required but should be verified for specific plans, particularly for high-frequency monitoring. Some payers impose annual frequency limits aligned with or more restrictive than Medicare LCD criteria. Verify plan-specific policies when performing more than two OCT optic nerve studies per year per eye.

Medicaid

Medicaid coverage for 92133 varies by state and managed care plan. State fee-for-service Medicaid programs often follow Medicare coverage logic with lower fee schedules. Managed Medicaid plans may require prior authorization for diagnostic imaging beyond a defined frequency. Verify state-specific Medicaid rules and any plan-level TAR requirements before high-frequency imaging in this population.

Common Denials & Prevention

Denial: MUE exceeded (units = 2 for bilateral imaging) Units billed as 2 trigger an automatic MUE denial at the MAC. Prevention: Bill 1 unit for all 92133 claims regardless of how many eyes are imaged. If only one eye is imaged, bill 1 unit with LT or RT.

Denial: Insufficient documentation (missing interpretation) The claim pays but is retracted on post-payment audit, or is denied on pre-payment review, because the medical record contains only the OCT device printout with no separate physician interpretation. Prevention: Implement a documentation workflow that requires a distinct signed interpretation note in the EMR before the claim is submitted. The interpretation must reference specific OCT findings and their clinical significance.

Denial: Non-covered diagnosis / medical necessity not established The primary diagnosis on the claim does not meet LCD criteria (e.g., routine screening, refractive error only). Prevention: Confirm the ICD-10-CM code mapped to 92133 belongs to the covered diagnosis categories (H40.xx, H46.xx, H47.xx, or other LCD-specified optic nerve conditions). If multiple diagnoses are present, sequence the condition driving the OCT as the primary diagnosis for the line item.

Denial: Bundled with excluded code 92133 denied when billed same-day as 92227, 92228, 92229, or 92250. These are AMA CPT codebook exclusions and are not modifier-bypassable. Prevention: Implement claim scrubbing rules that flag these combinations before submission. There is no appeal pathway based on medical necessity for codebook-excluded pairs.

Denial: Frequency exceeded without supporting documentation MAC denies a third or fourth 92133 claim within the same benefit period under LCD frequency limits. Prevention: When imaging frequency exceeds the LCD standard interval, ensure the medical record contains explicit documentation of clinical necessity for more frequent monitoring (e.g., "patient shows RNFL progression on serial OCT, requiring quarterly monitoring to assess rate of loss and guide treatment escalation"). Include this rationale in the appeal with the relevant OCT comparison reports.

Coding Scenarios

Scenario 1: A patient with bilateral primary open-angle glaucoma, right eye mild stage (H40.1131) and left eye mild stage (H40.1132), presents for a 6-month structural monitoring visit. OCT of both optic nerves is performed. The physician documents RNFL thickness values for each eye, compares to the prior year study, notes stability, and signs a written interpretation report.

Correct coding: 92133 (1 unit, no modifier, no LT/RT) + H40.1131, H40.1132

Why: One unit covers bilateral imaging per the "unilateral or bilateral" descriptor and MUE of 1. Laterality modifiers are omitted when both eyes are imaged. The written interpretation satisfies the documentation requirement.

Scenario 2: A patient presents with sudden visual field loss, left eye only. OCT of the left optic nerve is performed to evaluate for RNFL thinning consistent with ischemic optic neuropathy. The right eye is not imaged.

Correct coding: 92133-LT (1 unit) + H47.012

Why: Modifier LT specifies that only the left eye was imaged. One unit remains correct for unilateral imaging. H47.012 (ischemic optic neuropathy, left eye) provides the ICD-10-CM medical necessity support for optic nerve analysis.

Scenario 3: A patient has both glaucoma (H40.1130, bilateral, stage unspecified) and diabetic macular edema (E11.311 right eye, E11.312 left eye). At the same visit, the physician performs a full optic nerve OCT (RNFL/ONH protocol) and a separate macular thickness OCT with retinal layer analysis. Two distinct device protocols are run; two separate written interpretations are documented.

Correct coding: 92133 (1 unit) + 92134-59 or 92134-XS (1 unit); link 92133 to H40.1130 and 92134 to E11.311 and E11.312. Verify NCCI PTP edit status and modifier indicator for the current quarter.

Why: These codes image anatomically distinct structures with separate clinical indications. Both are payable when documentation supports each. Modifier XS (separate structure) or 59 is appended to bypass any active NCCI PTP edit. Multiple Procedures Indicator 7 applies a TC reduction to the lower-valued code's technical component.

Scenario 4: A hospital-based ophthalmology practice operates an OCT device in the outpatient clinic. The patient has ocular hypertension bilaterally (H40.053). The hospital operates the equipment; the ophthalmologist (employed by a separate medical group) interprets the scan and documents a signed written report.

Correct coding: Hospital bills 92133-TC (no APC payment generated; code is STV-Packaged). Physician group bills 92133-26 + H40.053.

Why: PC/TC Indicator 1 permits split billing. The facility's TC generates no incremental revenue in HOPPS due to APC packaging; the professional interpretation is paid separately under the PFS. Both claims together equal the global; neither should bill the global code.

Related Codes

• 92132 — OCT, anterior segment; used for cornea, angle, and iris imaging
• 92134 — OCT, posterior segment, retina; macular thickness and retinal layer analysis
• 92137 — OCT, posterior segment, retina with OCT angiography; adds retinal vascular mapping
• 92083 — Visual field examination; functional complement to 92133's structural data in glaucoma workup
• 92250 — Fundus photography; explicitly excluded from same-date billing with 92133 per AMA CPT codebook
• H40.1130 — Primary open-angle glaucoma, bilateral, stage unspecified; primary supporting diagnosis
• H40.053 — Ocular hypertension, bilateral; common glaucoma suspect indication
• H47.012 — Ischemic optic neuropathy, left eye; representative optic nerve disorder indication

Sources

1. AMA CPT Codebook — CPT 92133, 92132, 92134, 92137 official descriptions, billing indicators, code history, and codebook exclusions — verified via CodingAhead AMA CPT database, 2026-03-18
2. CMS Physician Fee Schedule Search Tool — RVU values and PFS status indicators for 92133; verify for CY2025 and CY2026
3. CMS Medicare Coverage Database — LCD search — MAC LCD articles governing posterior segment OCT; coverage criteria, frequency limits, and documentation requirements
4. CMS NCCI Edits — PTP and MUE Tables — current MUE value of 1, PTP edit pairs, and modifier indicators for 92133
5. HHS OIG Work Plan — ophthalmology diagnostic testing compliance risk areas