Optic nerve OCT
Spectral-domain OCT measures the retinal nerve fiber layer and ganglion cell complex, giving a structural baseline you can trend.
Glaucoma Care · Diagnostics
Glaucoma Diagnostics OCT, visual fields, tonometry, pachymetry and gonioscopy.
A glaucoma workup is a set of structural and functional tests read together and repeated over time. Here is what each instrument contributes, how the visit flows, and the codes Medicare contractors associate with each test.
5core tests in a glaucoma workup
2 per eyeOCT exams per year a Novitas policy expects for glaucoma
7 to 50 mmHgmeasuring range of the iCare IC200
1 per yearMedicare glaucoma screening for high-risk patients
What each test answers
Structure, function and the angle
Pressure tells you about risk, imaging shows the nerve and nerve fiber layer, fields show what the patient has lost, and the angle exam decides which kind of glaucoma you are treating.
Visual fields
Standard automated perimetry, typically a 24-2 threshold test with a 10-2 when central loss is suspected, documents function.
Tonometry
Goldmann applanation is the reference method. Rebound devices measure without anesthetic and suit children and screening.
iCarePachymetry and gonioscopy
Thinner corneas carried higher risk in OHTS. Gonioscopy separates open from narrow or closed angles before treatment.
OHTSBuilding the testing suite
Most practices already own a tonometer and slit lamp. OCT and a perimeter are the two capital purchases that make in-house glaucoma management possible.
- OCT with a glaucoma analysis package
- Threshold perimeter with progression software
- Pachymeter and gonioscopy lens
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OCT platforms
Common choices include ZEISS CIRRUS, Heidelberg SPECTRALIS and Topcon Maestro2. Compare their normative databases and progression reports.
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Perimetry
The ZEISS Humphrey Field Analyzer is the widely used reference perimeter. Faster threshold strategies shorten testing time for patients.
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Rebound tonometry
iCare's IC200 measures pressure from 7 to 50 mmHg without anesthetic or an air puff, seated, reclined or supine.
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Angle assessment
A four-mirror gonioscopy lens stays essential. Anterior segment OCT adds a documented image of the angle.
The visit
A baseline workup in three steps
Delegate the imaging and fields to trained staff with a written order, then review everything together at the doctor's exam.
Measure
Pressure, central corneal thickness and family and medical history, including steroid use and diabetes.
Image and test
Optic nerve and ganglion cell OCT, then threshold fields. Repeat a first field that looks abnormal, since learning effects are common.
Examine and decide
Gonioscopy and a dilated nerve exam, then classify the patient as a suspect, ocular hypertensive or glaucoma and set the follow-up interval.
Coding and frequency notes
Common CPT and HCPCS codes
| 92133 | Scanning computerized ophthalmic imaging, posterior segment, optic nerve (OCT). Billed once for one or both eyes |
|---|---|
| 92083 | Visual field examination, extended (threshold) |
| 92020 | Gonioscopy |
| 76514 | Corneal pachymetry by ultrasound, unilateral or bilateral |
| 92250 | Fundus photography; contractors treat it as an edit with 92133 |
| G0117 | Medicare glaucoma screening by an optometrist or ophthalmologist |
| G0118 | Medicare glaucoma screening under the direct supervision of an optometrist or ophthalmologist |
Frequency guidance from contractor policies
- Novitas expects about two OCT exams per eye per year for a patient being managed for glaucoma
- 92133 and the retina OCT code 92134 are mutually exclusive on the same day
- Pachymetry is typically covered once per lifetime; an ABN applies if repeated for Medicare
- Visual fields at unusually short intervals may be reviewed
Who qualifies for Medicare glaucoma screening
- People with diabetes
- People with a family history of glaucoma
- African Americans age 50 and older
- Hispanic Americans age 65 and older
Delegation
When a technician performs a test, keep a written order in the medical record naming the test and the eye or eyes, plus the medical necessity and the doctor's interpretation and report.
Questions about glaucoma testing
Do I need both OCT and fields?
Yes for most patients. OCT shows structural change and perimetry shows function, and early disease can appear in one before the other.
How often should OCT be repeated?
It depends on stage and stability. One Medicare contractor expects about two OCT exams per eye per year for a glaucoma patient, and frequent repeats need documented reasons.
Is rebound tonometry accurate enough?
Rebound tonometers are widely used for screening and for patients who cannot sit at the slit lamp. Confirm borderline or treatment-changing readings with Goldmann applanation.
Why measure corneal thickness?
In the Ocular Hypertension Treatment Study, people who developed glaucoma tended to have thinner corneas, so pachymetry refines risk.
Can the Medicare screening code be billed with an exam?
G0117 and G0118 cover screening for high-risk beneficiaries once a year. Diagnostic tests for a patient with signs or a diagnosis are billed with their own codes.
Does Vision Rescue sell OCT or perimeters?
Capital equipment is purchased from the manufacturer. Vision Rescue supplies the diagnostic consumables and stains used around these tests.
References
Make glaucoma testing a routine service
Pair the right instruments with a clear testing schedule, and stock the stains and supplies that go with every workup.
Written for licensed eye care professionals. Coding information is general and payer policies change; confirm current CPT descriptors, local coverage determinations and scope of practice before billing. Product names are trademarks of their owners.