HCPCS Code G0118: Glaucoma screening billing guide

Key takeaways

HCPCS Code G0118 covers glaucoma screening for a high-risk Medicare patient, performed under an optometrist’s or ophthalmologist’s direct supervision.

Four high-risk categories qualify: diabetes mellitus, family history of glaucoma, African Americans aged 50 and older, and Hispanic Americans aged 65 and older.

Bill G0117 when the provider performs the screening personally, and G0118 when a staff member performs it under supervision.

Medicare pays for one screening every 12 months, counted from the last service date rather than the calendar year.

Patients still owe coinsurance and the Part B deductible, so glaucoma screening is not a zero-cost preventive benefit.

HCPCS Code G0118 is the Medicare code for a glaucoma screening on a high-risk beneficiary, furnished under the direct supervision of an optometrist or ophthalmologist. A staff member performs the screening while the supervising provider stays on site.

This reference covers who counts as high risk and which ICD-10 codes to pair with the claim. It also explains how G0118 differs from G0117 and what Medicare expects in the record.

HCPCS Code G0118: Definition and code details

HCPCS Code G0118 is an HCPCS Level II G-code maintained by the Centers for Medicare and Medicaid Services, or CMS. It is not a CPT code.

G-codes cover Medicare services with no equivalent CPT descriptor, from therapy codes such as G0159 to preventive screening codes like G0118. G0118 sits in the preventive services category under Medicare Part B.

The official CMS descriptor for HCPCS Code G0118 is: Glaucoma screening for high risk patient furnished under the direct supervision of an optometrist or ophthalmologist.

The phrase that decides the code is “direct supervision.” The supervising optometrist or ophthalmologist must be in the office suite and immediately available. They do not conduct the examination themselves.

G0118 vs G0117: Key differences

Choosing between G0117 and G0118 comes down to one question. Who physically performs the glaucoma screening? The CMS preventive services chart lists G0117 as the screening by an optometrist or ophthalmologist.

G0118 is the same screening under their direct supervision. Both codes need a qualifying provider, in different roles.

Practices that use ophthalmic technicians for initial tonometry or visual field screening will most often bill G0118. The supervising provider may review the findings afterward. Who performed the screening still decides the code, so the billing workflow should ask that question first.

Who counts as a high-risk patient

Medicare does not cover glaucoma screening for the general beneficiary population. Only patients who meet at least one of four CMS-defined high-risk criteria are eligible. A claim for anyone outside those four criteria will be denied. Clean coding does not rescue an ineligible patient.

• Diabetes mellitus: Any Medicare beneficiary with a confirmed diabetes diagnosis qualifies. The diagnosis often starts with a primary care or metabolic health practice, so ask for it at intake.
• Family history of glaucoma: A documented first-degree family history of glaucoma, meaning a parent, sibling, or child. The history has to be written into the medical record, not just mentioned verbally.
• African Americans age 50 and older: Medicare treats this group as high risk on the strength of population data showing far higher glaucoma prevalence. The patient must be 50 or older on the day of the screening.
• Hispanic Americans age 65 and older: Hispanic or Latino patients aged 65 and above qualify under the same population-level risk category. The threshold here is 65, not 50.

A patient can qualify under more than one criterion. Only one qualifying diagnosis has to appear as the reason for the screening. The record must show that status before the claim goes out. Medical forms management tools can put the high-risk question in the intake form, so the answer arrives at registration.

ICD-10 codes that support the claim

Every G0118 claim requires a supporting ICD-10-CM diagnosis code that establishes the patient’s high-risk status. The diagnosis code communicates medical necessity to the Medicare Administrative Contractor (MAC) processing the claim. Using an unrelated or non-covered ICD-10 code is a guaranteed denial.

Always check covered diagnosis codes against the current Local Coverage Determination, or LCD, for your MAC jurisdiction. Covered code lists change between fiscal years. Established glaucoma codes such as H40.9 or H42 may also appear once a screening finds disease. Confirm MAC acceptance before you rely on those pairings.

Medicare coverage and frequency rules

Medicare Part B covers G0118 once every 12 months for a qualifying high-risk beneficiary. The window runs from the date of the last covered screening, not from January 1. Practices that treat it as a calendar-year benefit rebill too early and get denied.

Glaucoma screening is not one of the preventive services Medicare covers at no cost to the patient. CMS lists coinsurance and the Part B deductible as applying to both G0117 and G0118. Tell patients that before the visit rather than after the statement arrives.

Storing each patient’s screening history in electronic client records lets billing staff check the 12-month clock before the appointment. Other Medicare screening codes such as G0106 run on the same clock, so one frequency check can cover several services.

Reimbursement rate and fee schedule

Medicare reimbursement for HCPCS Code G0118 is set annually through the Medicare Physician Fee Schedule, or MPFS. Rates are adjusted using geographic practice cost indices, so a practice in Manhattan sees a different allowable amount than one in rural Mississippi.

Any dollar figure published in a third-party billing resource may be out of date by the time you read it.

Query the current year’s MPFS directly with the CMS fee schedule tool. Enter G0118 with your MAC locality code. The code carries a facility rate for outpatient hospital and ambulatory surgery center settings, and a separate non-facility rate for a physician office. The non-facility rate is usually higher because it includes practice overhead.

Rates change each January 1 and can shift mid-year through the conversion factor update. Pull fresh MPFS data at the start of each year and after any CMS correction. The AAPC HCPCS lookup is a useful cross-reference for descriptors and coverage notes. Confirm payment rates at the CMS source itself.

Billing guidelines for ophthalmology practices

Getting G0118 paid on the first submission takes more than the right code. Each item below is a documented denial reason for this code across MAC jurisdictions.

• Confirm high-risk status before billing: The record must document which of the four qualifying criteria applies. “Patient is high risk for glaucoma” will not satisfy an auditor without the criterion named.
• Select the correct supervision code: Use G0118 only when someone other than the supervising optometrist or ophthalmologist performs the screening. If the provider does it personally, use G0117.
• Use the correct place of service code: Most G0118 claims are filed with POS 11 for office. A POS code that does not match where the service happened is a frequent edit trigger.
• Apply the 12-month rule from the last service date: Wait a full 12 months from the prior paid claim date. The calendar year has nothing to do with it.
• Watch for bundling edits: Check your MAC LCD for flags that bundle G0118 with other ophthalmic services billed on the same day.
• Include the qualifying ICD-10 code: List the high-risk diagnosis as the primary or secondary diagnosis on the claim. Z13.5 on its own may not satisfy every MAC LCD, so add the underlying condition code where it applies.

Code-level rules built into the place where the note is written shorten the trip from documentation to a clean claim. That is the part of the medical billing process a practice controls most directly. Several other G-codes also turn on who furnished the service, G0128 among them, so the same question belongs in every claim review.

Documentation Medicare expects in the record

Medicare expects specific elements in the record behind a G0118 claim. Missing one of them is enough for a MAC to recoup payment on audit. Digital intake forms that capture the high-risk criterion at registration keep that evidence in the chart from day one.

• High-risk status justification: The record must name which criterion applies, whether that is diabetes, family history, or a qualifying demographic risk. Back it up with the active problem list or the patient-reported history.
• Supervising provider credentials: Documentation must identify the optometrist or ophthalmologist whose direct supervision covered the service. The provider’s NPI should match what appears on the claim.
• Screening findings: The note must carry the clinical findings. That means intraocular pressure readings, visual field results, or dilated fundus findings, whichever the screening produced.
• Date of service: Record the exact date. It has to fall at least 12 months after the patient’s last G0118 or G0117 claim.
• Staff performing the service: The record should show that a qualified staff member ran the screening, and it should name the supervising provider.

Practices with separate EHR and billing systems hit a familiar problem. The clinical note lives in one system, the claim is built in another, and nobody reconciles the two before submission. EHR integration that feeds the note straight into the billing queue keeps the supporting evidence with the claim.

Diabetes diagnoses and family history often arrive from a primary care practice. Your own record still has to carry them, because a MAC reviews what you documented.

Common billing errors and how to avoid them

G0118 denials follow predictable patterns. Billing teams that flag these specific scenarios in their pre-submission edit process will catch the majority of preventable rejections before they reach the MAC.

• Error: Using G0118 when the provider performed the screening personally. Fix: Confirm who conducted the exam. If it was the optometrist or ophthalmologist, switch to G0117 before submission.
• Error: Missing the high-risk ICD-10 code on the claim. Fix: Make the qualifying diagnosis a required field in your billing workflow. A claim carrying only a screening Z-code, with no underlying condition or demographic risk, often denies at the MAC.
• Error: Billing G0118 within 12 months of the last screening claim. Fix: Build a frequency check that flags any patient whose last G0118 or G0117 claim was under 12 months ago.
• Error: Incorrect place of service code. Fix: Verify POS against the service location at claim creation rather than a default template. POS 11 and POS 22 pay differently.
• Error: Billing G0118 with a same-day diagnostic service and no modifier. Fix: Check your MAC LCD for bundling edits. Append the right modifier when a diagnostic exam is billed on the same date.

Denial review belongs in your revenue cycle management routine. Pull the G0118 denial rate monthly and sort the denials by error type. Then fix the top two or three root causes instead of reworking claims one at a time. Practices that track denials at the code level see patterns a general billing review would miss.

How Pabau prevents G0118 coding and frequency errors

Ophthalmology and optometry practices that code G0118 by hand carry a structural risk. The facts that decide the claim sit in three different places, and nobody reconciles them before submission. The exam record, the screening history, and the risk factor all have to line up.

Pabau keeps all three in one place, inside the clinical record. Pabau’s claims management software attaches G0118 to the encounter as the note is written. The ICD-10 code that establishes high-risk status is chosen in the same step, so the note and the claim leave together.

Three workflows carry most of the load for practices billing G0118 regularly:

• Frequency tracking: Pabau flags any patient whose last G0118 claim falls inside the 12-month window, before the scheduler books the next screening.
• High-risk documentation prompts: Intake forms built in Pabau ask the qualifying-criterion question at registration and store the answer on the patient’s record.
• Code-level audit trails: Pabau records which provider supervised the service next to the clinical note, so an audit request does not become a reconstruction job.

It is worth reviewing which practice management features reach past scheduling into claims work. Automated workflows can catch a frequency error, a missing diagnosis, or an unnamed supervisor before the claim leaves the practice. That is where a G0118 denial pattern stops.

Reduce G0118 denials with cleaner claim data

Pabau links the HCPCS code, the supporting diagnosis, and the clinical note in one step. Your billing team can see the frequency clock before the claim goes out.

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Conclusion

Three checks decide whether G0118 gets paid. Confirm who performed the screening, attach a diagnosis that proves high-risk status, and count 12 months from the last service date. Build those checks into the workflow and the denial queue stops refilling itself.

Tell patients about the coinsurance before the visit as well. That one conversation prevents most of the billing complaints that follow a screening. Book a demo to see how Pabau links the code, the diagnosis, and the record on every G0118 claim.

Continue your research

Tracking denials across the whole practice? Healthcare revenue cycle management shows where denial review fits the wider process.

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