76516

🎯CPT 76516 — Ophthalmic Biometry by Ultrasound Echography, A-scan

Code Overview

CPT 76516 describes ophthalmic biometry performed by ultrasound echography using an A-scan — a one-dimensional ultrasonic measurement technique that quantifies the axial length of the eye and, in the biometry context, measures the distances between key intraocular structures. It represents the measurement-only component of ultrasound-based ocular biometry — the acquisition of axial length data without the accompanying intraocular lens (IOL) power calculation formula step that characterizes its sister code, CPT 76519.

CPT 76516 occupies a critically specific and often misunderstood niche in ophthalmology billing. It is a Bilateral Indicator 2 code — meaning all three components (global, technical, and professional) are inherently bilateral, and standard bilateral modifiers (-50, -RT, -LT) should not be used with this code. If performed unilaterally, Modifier -52 (reduced services) must be appended. Its billing and coverage landscape is nuanced: while 76516 is a valid, payable code for axial length measurement not associated with IOL calculation, Medicare does not cover it as a standalone service when the only indication is a cataract with planned surgery — in that context, 76519 (biometry with IOL power calculation) is the appropriate and covered code.

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Full Code Description

Element	Detail
CPT Code	76516
Full Descriptor	Ophthalmic biometry by ultrasound echography, A-scan
Section	Diagnostic Ultrasound, Head and Neck (76506-76536)
System	Eye and Ocular Adnexa — Diagnostic Imaging
Global Period	XXX — Concept not applicable; diagnostic/radiology procedure
wRVU (global)	~0.57
wRVU (-26 professional component)	~0.20
Facility Total RVU	~0.70
Non-Facility Total RVU	~1.28
Medicare ~Payment (global, 2025)	~$18-$22 (geographically adjusted)
Bilateral Indicator	2 — Inherently bilateral; do NOT use -50, -RT, -LT
Unilateral Performance	Report with Modifier -52 (reduced services)
Split Billing (TC/26)	Modifier -TC (technical) / Modifier -26 (professional component)
Separate Procedure	No
Assistant Surgeon	Not applicable
Add-On Code	No
Telehealth	No
ASC Eligible	Yes (when medically necessary as standalone)

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Clinical Description

What Is an A-scan in Ophthalmology?

The term A-scan refers to an A-mode (amplitude-mode) ultrasound — a one-dimensional ultrasonic echo technique that displays tissue interfaces as peaks (spikes) of varying amplitude along a horizontal time axis. Unlike B-scan (brightness mode) ultrasound, which creates a two-dimensional cross-sectional image, the A-scan does not produce a visual image of anatomical structures. Instead, it represents ultrasound echoes returning from successive tissue interfaces within the eye as vertical spikes displayed on a linear amplitude trace.

Basic physics:
A piezoelectric transducer in the A-scan probe emits a focused beam of ultrasound waves (typically at 10 MHz for ophthalmic use) into the eye. As the beam encounters tissue interfaces with different acoustic impedances (the cornea-aqueous interface, the aqueous-lens interface, the posterior lens capsule-vitreous interface, and the vitreoretinal interface), a portion of the sound energy is reflected back to the transducer. The time delay between emission and echo return is proportional to the distance traveled through the tissue, and since the speed of sound in ocular tissues is known (cornea/lens ~1641 m/s; aqueous/vitreous ~1532 m/s), precise distance measurements can be calculated.

Key ocular distance measured — axial length:
The most clinically essential measurement derived from ophthalmic A-scan biometry is the axial length (AL) of the eye — the distance from the anterior surface of the cornea to the retinal pigment epithelium (macula). Normal adult axial length is approximately 22-26 mm (mean ~23.5 mm). Axial length is the single strongest determinant of refractive error and is foundational to IOL power calculation.

Other A-scan biometry measurements:
Beyond axial length, the A-scan also measures:

• Anterior chamber depth (ACD) — from the posterior corneal surface to the anterior lens surface; normal ~2.5-3.7 mm in phakic eyes

• Lens thickness (LT) — from the anterior to posterior lens capsule; normal ~3.5-5 mm (increases with age and cataract development)

• Vitreous chamber depth (VCD) — from the posterior lens capsule to the internal limiting membrane; approximately 14-17 mm

Note

These measurements collectively characterize the biometric dimensions of the eye and are used in IOL power calculation formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1 and 2, SRK/T, Kane formula) when 76519 or 92136 is performed.

A-scan Technique — Contact Method (CPT 76516)

Contact A-scan is the traditional, probe-to-cornea technique. A sterile probe tip (or gel-covered probe) is placed directly on the anesthetized corneal surface. The ultrasound beam is transmitted through the contact point into the anterior segment.

Important limitation of contact technique: Because the probe tip physically contacts the cornea, there is a risk of inadvertently compressing the cornea — even slightly. Corneal compression alters the apparent axial length measurement by shortening the cornea-to-retina distance, introducing measurement error of 0.1-0.3 mm. Since an error of only 1 mm in axial length corresponds to approximately 2.5 diopters of IOL power error, contact applanation A-scan (the technique inherent in the standard 76516 contact approach) carries measurable biometric imprecision compared to immersion A-scan or optical biometry (IOLMaster / Lenstar — CPT 92136).

Immersion A-scan technique:
An alternative A-scan technique using an immersion shell (Prager shell or similar scleral cup) filled with saline or methylcellulose is placed over the eye, creating a water bath that suspends the probe above the cornea without contact. This eliminates the corneal compression artifact and produces more reproducible measurements. Immersion A-scan is generally considered more accurate than contact applanation A-scan for IOL power calculation. The code for immersion A-scan with IOL calculation is CPT 76519 — not 76516.

Contact vs. immersion methodology note: CPT 76516 encompasses standard ophthalmic biometry A-scan, which may be performed by either contact or immersion technique. The distinction between 76516 (without IOL calculation) and 76519 (with IOL calculation) is not technique-specific — it is based on whether IOL power calculation is performed.

A-scan vs. Partial Coherence Interferometry (Optical Biometry — CPT 92136)

Feature	A-scan (76516/76519)	Optical Biometry (92136)
Technology	Ultrasound (sound waves, 10 MHz)	Partial coherence interferometry (infrared light, ~780 nm)
Contact required	Yes (contact) or water bath (immersion)	No — non-contact
Measurement method	Time-of-flight of acoustic echoes	Time-of-flight of light reflections
Axial length accuracy	±0.1-0.3 mm (contact); ±0.05 mm (immersion)	±0.02-0.03 mm (highly precise)
Dense cataract	Can measure through dense/brunescent cataracts	Cannot measure through very dense cataracts (light cannot penetrate)
Patient cooperation	Easier for uncooperative patients (contact probe)	Requires fixation; non-contact but depends on light transmission
Additional measurements	Axial length, ACD, LT, VCD	Axial length, ACD, corneal curvature (K), WTW, pupil diameter
Preferred for IOL calculation	When OCB fails (dense cataract); historical standard	First-line for most modern practices
CPT	76516 (without IOL calc) / 76519 (with IOL calc)	92136 (always includes IOL calc)
NCCI relationship	76519 and 92136 are mutually exclusive	Cannot report 92136 and 76519 same visit

Note

Clinical and coding implication: In modern ophthalmology practices, 92136 (optical biometry — IOLMaster, Lenstar, Anterion) has largely replaced contact A-scan (76519) as the first-line method for IOL power calculation in patients with cataracts. Contact A-scan (76516/76519) remains essential when optical biometry cannot acquire a usable signal — specifically in patients with dense, brunescent cataracts where the light beam of the optical biometer cannot penetrate to the retina. In those cases, ultrasound A-scan is the only viable biometry method.

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What CPT 76516 Specifically Describes

CPT 76516 — without IOL power calculation — represents the A-scan measurement step alone: acquisition of axial length and other biometric measurements without the application of an IOL power calculation formula. This distinction is clinically and financially critical because:

• CPT 76519 = A-scan + IOL power calculation (the complete pre-cataract biometry service)

• CPT 76516 = A-scan only (measurement without the IOL formula calculation step)

Note

The technical component (TC) of 76516 represents the physical performance of the ultrasound measurement (probe use, waveform acquisition, data recording). The professional component (-26) represents the provider’s review, interpretation, and formal report of the biometric data.

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When CPT 76516 Is the Appropriate Code

Axial Length Measurement for Conditions Other Than IOL Power Calculation

The primary appropriate use of 76516 (rather than 76519) is when axial length or other biometric measurements are needed for clinical purposes not involving IOL power calculation:

Monitoring myopia progression:

• Children and young adults with progressive myopia require serial axial length measurements to document the rate of eye elongation and to monitor response to myopia management therapies (orthokeratology, atropine, myopia control spectacle lenses, multifocal contact lenses)

• Axial length measurement is now a standard component of myopia management protocols; the rate of axial elongation (mm/year) is a primary outcome measure

• 76516 is appropriate here — there is no IOL calculation being performed

Monitoring ocular conditions affecting globe size:

• Buphthalmos (congenital glaucoma) — axial length is dramatically increased; serial measurements track IOP control effectiveness and rate of progressive globe enlargement

• High myopia surveillance — monitoring for staphyloma progression, posterior pole thinning, and axial elongation in patients with pathologic myopia (> -6 diopters; axial length >26 mm)

• Proptosis/exophthalmos — assessing anterior globe displacement; axial length in the context of orbital disease

• Nanophthalmos/microphthalmos — anomalously small eyes; biometry confirms diagnosis and quantifies the degree of microphthalmos (axial length typically < 19 mm)

• Post-surgical monitoring — following scleral buckle, macular translocation, or other posterior segment procedures that may affect axial length or biometric parameters

Detecting intraocular masses or tumors:

• A-scan biometry in the tumor evaluation context (e.g., measuring the height/thickness of a choroidal melanoma, retinoblastoma, or choroidal metastasis) provides dimensional data that supplement B-scan findings

• Note: for primary evaluation of intraocular masses, CPT 76510 (ophthalmic ultrasound, echography, diagnostic; contact B-scan with or without simultaneous A-scan) or 76511 (quantitative A-scan only) may be more appropriate codes; context matters

Research, screening, and population studies:

• Axial length measurement in population studies, clinical trials, or screening programs where biometry data is collected independent of surgical planning

When 76516 Is NOT the Appropriate Code (Use 76519 Instead)

Cataract surgery IOL planning:

• When the A-scan is being performed specifically to plan cataract surgery and determine the IOL power, CPT 76519 (ophthalmic biometry with IOL power calculation) is the correct code — not 76516

• Medicare covers 76519 for cataract patients; it does not cover 76516 as a standalone service when the only diagnosis is cataract with planned surgery

• 76516 submitted with a cataract-only diagnosis for IOL-planning purposes will typically be denied by Medicare as a non-covered service

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Bilateral Indicator 2 — Critical Billing Rules

This is the most technically complex and frequently misunderstood aspect of CPT 76516 billing. The code has a Bilateral Indicator of “2” in the Medicare Physician Fee Schedule Database (MPFSDB) — for all three components (global, TC, and professional).

What Bilateral Indicator 2 Means

A Bilateral Indicator of “2” means the CPT code is inherently bilateral — the procedure is, by definition, performed on both eyes (or is priced as a bilateral service). As a result:

• Do NOT use Modifier -50 (bilateral procedure) with 76516 — the code already accounts for bilateral performance

• Do NOT use Modifier -RT (right eye) or -LT (left eye) with 76516 — laterality modifiers are not appropriate for inherently bilateral codes

• Report the code once (1 unit) for bilateral performance — no doubling of units

Billing Table — 76516 (All Components Are BILAT Indicator 2)

Procedure Performed	Components	CPT Code	Modifier(s)	Units
Bilateral — global (TC + professional)	Both	76516	None	1
Bilateral — TC only	Technical only	76516	TC	1
Bilateral — professional component only	Professional only	76516	26	1
Unilateral — global (TC + professional)	Both, one eye	76516	52	1
Unilateral — TC only	Technical, one eye	76516	TC, 52	1
Unilateral — professional component only	Professional, one eye	76516	26, 52	1

Modifier -52 (reduced services) for unilateral performance: When biometry is performed on only one eye (e.g., the patient has already had cataract surgery in one eye and only the operative eye measurement is needed for the second surgery), Modifier -52 is appended to indicate the service was reduced/unilateral. This typically results in approximately 50% reduction in reimbursement, reflecting that only one eye’s data was acquired.

Note

Modifier priority: When both a component modifier (TC or 26) AND a reduced services modifier (-52) apply, the component modifier is placed in the first modifier field and -52 in the second modifier field, per Palmetto GBA and CMS billing guidelines for ophthalmic biometry codes.

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CPT Code Tree — Ophthalmic Diagnostic Ultrasound / Biometry Family

Diagnostic Ultrasound — Head and Neck (76506-76536)
  └── Ophthalmic Ultrasound / Biometry
        │
        ├── 76510    Ophthalmic ultrasound, diagnostic; contact B-scan
        │            with or without simultaneous A-scan
        │            (B-scan for posterior segment evaluation — vitreous, retina,
        │             choroid; dense cataract posterior eval; BILAT Ind. 1)
        │
        ├── [[76511]]    Ophthalmic ultrasound, diagnostic; quantitative A-scan only
        │            (Diagnostic A-scan for masses, lesions, tissue characterization;
        │             NOT biometry; BILAT Ind. 1; use -RT/-LT/-50)
        │
        ├── [[76512]]    Ophthalmic ultrasound, diagnostic; contact B-scan (with
        │            or without simultaneous A-scan) — separate from 76510
        │            (immersion B-scan and similar)
        │
        ├── [[76513]]    Anterior segment ultrasound, immersion (water bath) B-scan
        │            or high resolution biomicroscopy
        │            (UBM — ultrasound biomicroscopy; anterior segment; BILAT Ind. 1)
        │
        ├── 76516    Ophthalmic biometry by ultrasound echography, A-scan
        │            ◄ THIS CODE
        │            (Axial length measurement without IOL power calculation;
        │             BILAT Ind. 2; no -50/-RT/-LT; use -52 if unilateral;
        │             0 global days [XXX radiology]; wRVU ~0.57)
        │
        ├── 76519    Ophthalmic biometry by ultrasound echography, A-scan;
        │            with intraocular lens power calculation
        │            (Axial length + IOL formula calculation; primary IOL planning code;
        │             TC = BILAT Ind. 2; -26 professional = BILAT Ind. 3 [unilateral];
        │             NCCI mutually exclusive with 92136; use -26 twice [once per eye]
        │             if bilateral IOL calculation needed; wRVU ~0.74 for professional)
        │
        └── [[92136]]    Ophthalmic biometry by partial coherence interferometry
                     with intraocular lens power calculation
                     (IOLMaster, Lenstar, Anterion — optical biometry;
                      NCCI mutually exclusive with 76519; preferred first-line modality;
                      TC = BILAT Ind. 2; -26 = BILAT Ind. 3;
                      wRVU ~0.69 for professional; cannot report with 76519 same visit)

Critical Code Distinctions Within the Family

Code	Measurement	IOL Calculation	Technology	First-Line Use
76516	Axial length + biometry measurements	No	Ultrasound A-scan	Myopia monitoring; buphthalmos; non-IOL axial length measurement
[76519]]	Axial length + biometry measurements	Yes	Ultrasound A-scan	Cataract IOL planning when optical biometry fails (dense cataract)
92136	Axial length + ACD + keratometry + other	Yes	Optical (partial coherence interferometry)	Standard cataract IOL planning — first-line in most modern practices
76511	Tissue characterization / mass measurement	No (diagnostic)	Ultrasound A-scan	Intraocular tumors, mass evaluation — quantitative diagnostic scan
76510	Posterior segment visualization	No (imaging)	B-scan ± A-scan	Dense cataract posterior segment eval; vitreous/retina/choroid
76513	Anterior segment cross-section	No (imaging)	High-res B-scan / UBM	Angle anatomy, ciliary body, IOL position, anterior masses

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Includes / Excludes Notes

What Is Included in CPT 76516

• Patient preparation and positioning for ultrasound examination

• Topical anesthetic administration (if contact technique)

• Placement of ultrasound probe (contact technique) or immersion shell setup

• A-scan waveform acquisition

• Recording of axial length, ACD, lens thickness, and vitreous chamber depth measurements

• Multiple measurements (typically 5-8 per eye) for averaging and reproducibility

• Data documentation and storage

• Formal written interpretation and report of biometric findings (professional component)

What Is NOT Included (May Be Separately Reported)

• IOL power calculation — the application of an IOL formula to the biometric data to determine the appropriate IOL power is not included in 76516; when IOL calculation is performed, use 76519 instead of (or in addition to, if applicable) 76516

• B-scan ultrasound (76510, 76512) — if a B-scan is performed at the same session for posterior segment evaluation (e.g., dense cataract precluding fundus view), it is separately reportable with appropriate diagnosis linkage

• Ultrasound biomicroscopy (76513) — separately reportable if performed for anterior segment imaging

• Keratometry (92025 — corneal topography) — separately reportable when corneal measurements are performed independently for contact lens fitting or corneal disease evaluation; the K-readings in 92136 are bundled within that code

• Office visit / E/M — separately reportable with Modifier -25 if a significant, separately identifiable E/M service is performed at the same encounter

NCCI Bundles and Mutually Exclusive Codes

Code	Bundle Status With 76516	Notes
76519	Not bundled — both can be reported if clinically distinct	If axial length measurement (76516) and IOL calculation (76519) are legitimately separate services at different encounters, both are reportable; if performed at the same encounter, 76519 subsumes 76516 in most clinical contexts
92136	Not directly NCCI-bundled with 76516 (92136 bundles with 76519)	92136 and 76519 are mutually exclusive with each other; 92136 and 76516 are not explicitly mutually exclusive — but rarely clinically appropriate to report both
76510	Not bundled; separately reportable	B-scan for posterior segment evaluation has a distinct clinical purpose
76511	Not bundled; separately reportable with distinct indication	Diagnostic A-scan (mass/tumor evaluation) vs. biometry A-scan
76513	Not bundled; separately reportable with distinct indication	UBM (anterior segment imaging) vs. axial length measurement

76519 and 92136 mutual exclusivity: These two codes are NCCI mutually exclusive (modifier indicator “0”) — meaning Medicare will NEVER separately reimburse both 76519 and 92136 at the same patient encounter regardless of modifiers. If both ultrasound biometry and optical biometry are performed at the same session (because optical biometry failed in one eye and ultrasound was required as a backup), only the more comprehensive/higher-value code (92136) should be reported. The NCCI “0” indicator means no modifier can override this edit.

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HCC (Hierarchical Condition Category) Mapping

CPT 76516 itself carries no HCC value — CPT codes are procedural and do not directly map to HCC. The diagnosis codes reported alongside 76516 drive any applicable risk adjustment.

Commonly Paired ICD-10-CM	Description	HCC Mapping
H52.11	Myopia, right eye	Not HCC mapped
H52.12	Myopia, left eye	Not HCC mapped
H52.13	Myopia, bilateral	Not HCC mapped
H44.21	Degenerative myopia, right eye	Not HCC mapped
H44.22	Degenerative myopia, left eye	Not HCC mapped
H44.23	Degenerative myopia, bilateral	Not HCC mapped
Q15.0	Congenital glaucoma (buphthalmos)	Not HCC mapped
H40.1110	Primary open-angle glaucoma, right eye	Not HCC mapped
C69.21	Malignant neoplasm of choroid, right eye	HCC 12
C69.22	Malignant neoplasm of choroid, left eye	HCC 12
D31.21	Benign neoplasm of choroid, right eye	Not HCC mapped
D31.22	Benign neoplasm of choroid, left eye	Not HCC mapped
E10.39	Type 1 DM with other diabetic eye disease	HCC 18
E11.39	Type 2 DM with other diabetic eye disease	HCC 19

Choroidal melanoma and HCC 12: When 76516 (or its companion diagnostic code 76511) is used in the context of evaluating or monitoring a choroidal melanoma (C69.21/C69.22), the associated malignancy diagnosis maps to HCC 12 (Breast, Prostate, Colorectal, and Other Cancers and Tumors) — carrying significant HCC weight. Accurate, specific cancer coding with the biometry procedure is essential for risk adjustment in these patients.

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MS-DRG Mapping (Inpatient)

CPT 76516 is performed exclusively in outpatient settings (office, ASC, outpatient clinic). It is a diagnostic imaging service with no inpatient hospital application as a standalone procedure. MS-DRG assignment is driven by the underlying diagnosis and any concurrent inpatient procedures — not by 76516 itself.

When the condition prompting 76516 (such as choroidal melanoma, ocular trauma, or significant intraocular tumor) results in inpatient hospitalization, the relevant DRGs are those for the underlying condition, not for the biometry:

MS-DRG	Description	Relevant Context
113	Orbital Procedures with CC/MCC	Inpatient surgery for orbital/ocular malignancy requiring biometry for surgical planning
114	Orbital Procedures without CC/MCC	Same, without CC/MCC
116	Intraocular Procedures with CC/MCC	Intraocular surgery (tumor resection, vitreoretinal) requiring biometry pre-op
117	Intraocular Procedures without CC/MCC	Same, without CC/MCC
124	Other Disorders of the Eye with MCC	Medical admission for ocular condition (not surgical)
125	Other Disorders of the Eye without MCC	Medical admission

MDC: MDC 02 — Diseases and Disorders of the Eye (when the primary diagnosis is ocular)

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ICD-10-CM Diagnosis Codes Commonly Paired With CPT 76516

Myopia Monitoring (Primary Outpatient Indication)

ICD-10-CM	Description	Notes
H52.11	Myopia, right eye	Simple myopia
H52.12	Myopia, left eye
H52.13	Myopia, bilateral
H44.21	Degenerative myopia, right eye	Pathologic/high myopia — axial length >26 mm
H44.22	Degenerative myopia, left eye
H44.23	Degenerative myopia, bilateral
H52.01	Hypermetropia, right eye	When axial length is needed for refractive documentation
H52.02	Hypermetropia, left eye

Congenital and Developmental Conditions

ICD-10-CM	Description	Notes
Q15.0	Congenital glaucoma (includes buphthalmos)	Serial axial length to monitor globe enlargement with IOP control
Q11.2	Microphthalmos	Axial length to quantify degree of microphthalmos
Q11.1	Cryptophthalmos	Congenital lid/globe anomaly; biometry for sizing
H40.1110	Primary open-angle glaucoma, right eye	Glaucoma monitoring context

Intraocular Tumors and Masses

ICD-10-CM	Description	Notes
C69.21	Malignant neoplasm of choroid, right eye	Choroidal melanoma — HCC 12
C69.22	Malignant neoplasm of choroid, left eye
D31.21	Benign neoplasm of choroid, right eye	Choroidal nevus, hemangioma
D31.22	Benign neoplasm of choroid, left eye
D31.11	Benign neoplasm of iris, right eye
C69.31	Malignant neoplasm of choroid overlapping sites	Ciliary body extension
H35.31-	Nonexudative AMD, right eye	When posterior pole changes require axial length documentation

Post-Surgical Assessment

ICD-10-CM	Description	Notes
Z96.11	Presence of intraocular lens, right eye	Post-cataract IOL in place; axial length re-measurement for second eye planning or refractive assessment
Z96.12	Presence of intraocular lens, left eye
H59.811	Chorioretinal scars after surgery for detachment, right	Post-scleral buckle; buckle may change axial length
H59.812	Chorioretinal scars after surgery for detachment, left
H21.31	Implant membrane, right eye	IOL-related assessment

Retinal and Posterior Segment Conditions Requiring Biometry

ICD-10-CM	Description	Notes
H33.001	Unspecified retinal detachment with retinal break, right	Pre-surgical biometry planning
H31.402	Unspecified retinal detachment with retinal break, left
H35.001	Nonspecific background retinopathy, right eye
H44.001	Purulent endophthalmitis, right eye	Pre/post-surgical biometry if IOL planning involved

Trauma

ICD-10-CM	Description	Notes
S05.91XA	Unspecified injury of right eye and orbit, initial encounter	Post-traumatic globe assessment
S05.92XA	Unspecified injury of left eye and orbit, initial encounter
H44.611	Retained (old) magnetic foreign body in anterior chamber, right	Foreign body assessment; globe integrity

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Billing and Modifier Guidance

The TC/26 Split — When It Applies

CPT 76516 can be billed globally (full code, no modifier) when the same entity performs both the technical and professional components. Split billing is required when the technical and professional components are performed by different entities:

Scenario	How to Bill
Independent practice — performs both TC and 26	76516, no modifier, 1 unit
Hospital/facility — owns equipment (TC); physician reads (26)	Facility: 76516-TC / Physician: 76516-26
Teleretinal reading — tech performs scan at clinic; specialist reads remotely	Clinic: 76516-TC / Specialist: 76516-26
Unilateral performance — both TC and 26	76516-52, 1 unit
Unilateral TC only	76516-TC-52, 1 unit
Unilateral 26 only	76516-26-52, 1 unit

Modifier Placement Priority

Per CMS and Palmetto GBA billing guidelines:

• The component modifier (-TC or -26) must be placed in the FIRST modifier field

• The -52 (reduced services) modifier is placed in the SECOND modifier field

• Incorrect placement of modifiers is a common claim rejection cause

Site of Service (POS) Considerations

Site	Billing Notes
Office (POS 11)	Non-facility payment rate applies — higher total RVU; physician may bill global code if owns equipment; typically no facility fee
Outpatient Hospital (POS 22)	Facility payment rate applies to physician; hospital bills facility fee separately; physician bills -26 only
ASC (POS 24)	Facility fee from ASC; physician bills -26 for professional component
Independent Clinic (POS 49)	Facility and professional components may be billed by the clinic depending on setup

Note

Non-facility vs. facility RVU distinction: CPT 76516 has meaningfully higher total RVU (~1.28) in the non-facility setting (physician’s office, where the physician bears the overhead cost of the ultrasound equipment) than in the facility setting (0.70, where the facility absorbs equipment costs). This difference ($20) incentivizes performing biometry in the office rather than at a facility, as it partially compensates the practice for equipment investment.

Medicare Coverage Policy

Medicare LCD L34181 key requirement: Medicare covers 76519 (A-scan biometry with IOL power calculation) for patients with documented cataracts with planned cataract surgery. Medicare generally does not separately cover 76516 (axial length measurement without IOL calculation) in the cataract-only context because 76516 does not include the IOL calculation step that constitutes the medically necessary service for pre-surgical planning. Submit 76516 for the specific non-IOL indications described above (myopia monitoring, tumor evaluation, buphthalmos) with appropriate diagnosis code support.

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Coding Examples

Example 1 — Bilateral Axial Length Measurement for Myopia Monitoring, Office Setting

Clinical Scenario:
A 10-year-old female with progressive bilateral myopia is enrolled in a myopia management program. She was fitted with orthokeratology lenses 6 months ago. At her 6-month follow-up, the pediatric ophthalmologist performs bilateral A-scan biometry to document axial length and compare to the baseline. Axial lengths: OD 24.82 mm (baseline: 24.61 mm, change: +0.21 mm/6 months); OS 24.91 mm (baseline: 24.70 mm, change: +0.21 mm/6 months). Myopia progression noted as moderate. No IOL power calculation is performed.

ICD-10-CM:

• H52.13 — Myopia, bilateral (primary — documented myopia driving the biometric monitoring)

CPT:

• 76516 — Ophthalmic biometry A-scan, bilateral (global code, no modifier — physician owns equipment and interprets; bilateral indicator 2 = inherently bilateral; report once)

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Example 2 — Unilateral A-scan for Second Eye Pre-Cataract Assessment, Modifier -52

Clinical Scenario:
A 74-year-old male has already undergone successful cataract surgery OD with IOL implantation. He now presents for evaluation of his visually significant cataract OS. The ophthalmologist performs A-scan biometry OS only (the OD measurements from the prior surgery are already on file and do not need to be repeated). The new axial length OS will be used for comparison purposes and to support clinical documentation. No IOL power calculation is performed at this visit — that will be done at the pre-operative appointment using 92136-26.

ICD-10-CM:

• H25.12 — Age-related nuclear cataract, left eye (primary — operative eye)

• Z96.11 — Presence of intraocular lens, right eye (additional — right eye pseudophakic status)

CPT:

• 76516-52 — Ophthalmic biometry A-scan, unilateral (left eye) (Modifier -52 = reduced services, reflecting that only one eye was measured; approximately 50% payment reduction)

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Example 3 — Choroidal Melanoma Monitoring, Bilateral Biometry with TC/26 Split

Clinical Scenario:
A 65-year-old male with a known choroidal melanoma OD is followed every 6 months with ophthalmic ultrasound. At today’s visit, a certified ophthalmic ultrasound technician (employed by the hospital’s ophthalmology department) performs bilateral A-scan biometry on the patient in the outpatient clinic, measuring axial length bilaterally and recording data. The retinal specialist (who does not directly perform the scan) later reviews the waveforms and data, interprets the findings, and documents a formal written report. The hospital facility bills the technical component; the retinal specialist bills the professional component.

ICD-10-CM:

• C69.21 — Malignant neoplasm of choroid, right eye (primary — HCC 12)

• H52.11 — Myopia, right eye (additional if applicable)

CPT:

• Hospital facility bill: 76516-TC — Technical component, bilateral A-scan biometry

• Physician bill: 76516-26 — Professional component, bilateral A-scan biometry (interpretation and written report)

Supervision requirements: The technical component of an ultrasound study is generally billable by a facility or physician practice when performed under at least general supervision (for diagnostic radiologic services). Ensure proper supervision documentation aligns with your payer’s requirements.

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Example 4 — Buphthalmos Serial Monitoring, Bilateral, Office Setting

Clinical Scenario:
A 3-year-old male with primary congenital glaucoma (PCG) who underwent bilateral goniotomy (CPT 65820-50) 4 months ago is seen for a routine post-operative examination under anesthesia (EUA). As part of the EUA, bilateral A-scan biometry is performed to document axial length and assess whether globe enlargement has arrested since IOP control was achieved. Axial lengths: OD 23.1 mm (prior: 24.3 mm — reduced/stable following IOP normalization); OS 23.8 mm (prior: 24.8 mm). No IOL calculation is being performed.

ICD-10-CM:

• Q15.0 — Congenital glaucoma (primary — buphthalmos/PCG with ongoing monitoring)

CPT:

• 76516 — Ophthalmic biometry A-scan, bilateral (global; inherently bilateral; no modifier; performed under general anesthesia as part of EUA — biometry is performed by the ophthalmologist; the anesthesia is separately billed by the anesthesiologist)

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Example 5 — A-scan Biometry When Optical Biometry Fails (Dense Cataract) — Use 76519, Not 76516

Clinical Scenario:
A 79-year-old female with a very dense, brunescent cataract OD is scheduled for cataract surgery. At the pre-operative visit, the ophthalmologist attempts optical biometry (IOLMaster) but cannot obtain a reliable reading due to the density of the nuclear sclerosis. The technician switches to contact A-scan biometry, successfully measuring axial length and obtaining biometric data. The ophthalmologist then applies the SRK/T formula to calculate the IOL power.

ICD-10-CM:

• H25.11 — Age-related nuclear cataract, right eye (dense, brunescent — driving the need for ultrasound rather than optical biometry)

CPT:

• 76519-RT — Ophthalmic biometry A-scan with IOL power calculation, right eye

Critical pitfall avoided: In this scenario, 76519 (not 76516) is correct because the IOL power calculation WAS performed. If 76516 were submitted, it would be denied by Medicare since the only diagnosis is cataract with planned surgery, and 76516 does not include the IOL calculation step that Medicare requires for cataract biometry reimbursement. Always default to 76519 when biometry is performed specifically for IOL power calculation in a cataract patient.

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Example 6 — Biometry for Nanophthalmos, Unilateral, TC/26 Split

Clinical Scenario:
A 35-year-old female with known bilateral nanophthalmos (extremely short axial length) presents for evaluation for cataract surgery OD. Her axial length must be carefully measured to plan the very high-power IOL that will be needed. The ultrasonographer (independent contractor) performs the contact A-scan OD only. The ophthalmologist subsequently reviews the waveforms and data and writes a formal interpretation report. The ophthalmologist will later perform the full IOL calculation at the pre-operative visit using 76519-26-OD.

ICD-10-CM:

• Q11.2 — Microphthalmos, right eye (or H44.21 degenerative myopia-equivalent coding — document as directed by the clinical record; nanophthalmos coding may use Q11.2 or appropriate structural abnormality code)

• H25.11 — Age-related nuclear cataract, right eye (additional)

CPT:

• Ultrasonographer (entity/contractor): 76516-TC-52 — Technical component, unilateral right eye (TC first, -52 second in modifier field)

• Ophthalmologist: 76516-26-52 — Professional component, unilateral right eye (26 first, -52 second in modifier field)

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Example 7 — 76516 vs. 92136 — Do Not Report Both at Same Session

Clinical Scenario:
A 68-year-old male presents for pre-cataract biometry OD. The technician performs IOLMaster optical biometry (92136) successfully and obtains reliable axial length, ACD, keratometry, and white-to-white measurements. The IOL power is calculated. Separately, the provider orders a standard A-scan “for confirmation.” Both studies are performed at the same session.

ICD-10-CM:

• H25.11 — Age-related nuclear cataract, right eye

CPT:

• 92136 — Ophthalmic biometry by partial coherence interferometry with IOL power calculation (the complete, higher-value study; report this code only)

• 76519 or 76516 is NOT separately reportable at this session — 92136 and 76519 are NCCI mutually exclusive (indicator “0”), and no modifier can override this edit. Additionally, there is no clinical justification for repeating biometry with a second method when the first was successful.

Clinical and compliance note: Performing both optical biometry (92136) and ultrasound biometry (76519 or 76516) at the same session and billing both is a known audit pattern. The NCCI mutual exclusivity of 92136 and 76519 (modifier indicator “0”) means Medicare will never pay both. When optical biometry succeeds, it is the only reportable code. Ultrasound biometry (76519) is reserved for when optical biometry fails.

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Key Coding Pitfalls & Tips

• 76516 ≠ 76519. These two codes differ by one critical element: IOL power calculation. 76516 is axial length measurement only; 76519 adds the application of an IOL formula. When billing for cataract surgery pre-op biometry, 76519 (or 92136) is the correct code — not 76516. Submitting 76516 for cataract IOL planning will be denied by Medicare.

• Never use Modifier -50, -RT, or -LT with 76516. The Bilateral Indicator 2 designation means the code is already priced as bilateral. Adding bilateral or laterality modifiers will cause claim rejection or overpayment. Use Modifier -52 only when truly performing the procedure unilaterally.

• Modifier placement order matters. When both a component modifier (TC or -26) and Modifier -52 are needed, the component modifier must appear in the FIRST modifier field. Reversing the order causes claim processing errors at the MAC level.

• 92136 and 76519 are NCCI mutually exclusive (modifier indicator “0”). Never report both at the same patient encounter. When optical biometry succeeds, report only 92136. Reserve 76519 for when optical biometry fails (typically dense cataracts). 76516 and 92136 do not have the same direct mutual exclusivity, but reporting both at the same encounter is clinically redundant and will draw scrutiny.

• Split billing (TC/26) requires the correct provider/entity ownership. The -TC component belongs to the entity that owns the ultrasound equipment and employs the technician. The -26 component belongs to the interpreting physician. If both are the same entity, bill the global code with no modifier.

• Document medical necessity for 76516 beyond cataract IOL planning. When 76516 is used for myopia monitoring, tumor surveillance, or buphthalmos monitoring, the clinical documentation must clearly support the non-IOL indication. The diagnosis code(s) should reflect the specific clinical condition — not a cataract diagnosis — when the service is performed for monitoring purposes.

• Serial biometry for myopia management is an emerging area. As myopia management (orthokeratology, low-dose atropine, myopia control lenses) grows in clinical practice, serial axial length measurement with 76516 is increasingly performed. Payer coverage for myopia monitoring biometry varies — some commercial payers cover it; others consider it investigational or not medically necessary for routine myopia management. Verify payer policies before billing 76516 for pediatric myopia monitoring.

• Unilateral performance requires careful documentation. When Modifier -52 is used, the operative report or procedure note must clearly document which eye was measured and the clinical reason only one eye required biometry (e.g., second-eye pre-cataract assessment when first eye already has an IOL; or single-eye tumor measurement). Without this documentation, the unilateral billing cannot be substantiated.

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Related Codes (Cross-Reference)

Code	Type	Description
76519	CPT	Ophthalmic biometry A-scan with IOL power calculation — primary cataract biometry code
92136	CPT	Ophthalmic biometry by partial coherence interferometry with IOL power calculation (IOLMaster, Lenstar) — first-line IOL planning modality; NCCI mutually exclusive with 76519
76510	CPT	Ophthalmic ultrasound, diagnostic; contact B-scan ± A-scan — posterior segment evaluation
76511	CPT	Ophthalmic ultrasound, diagnostic; quantitative A-scan only — diagnostic tissue characterization
76513	CPT	Anterior segment ultrasound, immersion B-scan or UBM — anterior segment anatomy
76512	CPT	Ophthalmic ultrasound, B-scan (contact)
92025	CPT	Corneal topography — separately reportable when corneal mapping is performed
66984	CPT	Cataract extraction, routine — frequently associated procedure when 76519 or 92136 is performed
66982	CPT	Cataract extraction, complex
H52.11	ICD-10-CM	Myopia, right eye
H52.12	ICD-10-CM	Myopia, left eye
H52.13	ICD-10-CM	Myopia, bilateral
H44.21	ICD-10-CM	Degenerative myopia, right eye
H44.22	ICD-10-CM	Degenerative myopia, left eye
H44.23	ICD-10-CM	Degenerative myopia, bilateral
Q15.0	ICD-10-CM	Congenital glaucoma — buphthalmos monitoring
Q11.2	ICD-10-CM	Microphthalmos — biometry for surgical planning
C69.21	ICD-10-CM	Malignant neoplasm of choroid, right eye — HCC 12
C69.22	ICD-10-CM	Malignant neoplasm of choroid, left eye — HCC 12
D31.21	ICD-10-CM	Benign neoplasm of choroid, right eye
D31.22	ICD-10-CM	Benign neoplasm of choroid, left eye
Z96.11	ICD-10-CM	Presence of intraocular lens, right eye
Z96.12	ICD-10-CM	Presence of intraocular lens, left eye

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Last Reviewed: 2026-02-18 | Source: AMA CPT Professional Edition 2025, CMS MPFS 2025, Palmetto GBA Ophthalmic Biometry Coding Guidelines, CMS LCD L34181 Ophthalmic Biometry for IOL Calculation, CMS NCCI Policy Manual 2025, AAPC Ophthalmology Coding Alert Bilateral Rules, ICD-10-CM FY2025