NPI registry status
Active
2026 NPPES data Glaucoma Specialist (Ophthalmology) Physician NPI 1457988065 MD
Verify on CMS → Robert Gunzenhauser, MD
Glaucoma Specialist (Ophthalmology) Physician in Upland, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 383 in Glaucoma Specialist (Ophthalmology) Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
1K
Medicare Part D claims · 598 beneficiaries · Glaucoma Specialist (Ophthalmology) Physician avg: 3K
Generic prescribing
61%
generic claims · 39% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$325.42
3 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2024
What the federal data shows
Robert Gunzenhauser, MD filed 1,442 Medicare Part D claims in 2024 as a Glaucoma Specialist (Ophthalmology) Physician in Upland, California, prescribing 61% generic.
- 1K
- Part D claims, 2024
- 61%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥80th
- pct by Part D claim volume (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Federal trust snapshot
What official records show about Robert Gunzenhauser, MD
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1457988065), first enumerated 03/24/2020.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 1,442 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- Reported
Industry payment transparency
$325.42 in reported industry payments (3 transfers) in 2024 under the federal Sunshine Act — disclosed transfers of value, not a quality rating.
Source: CMS Open Payments
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not Robert Gunzenhauser, MD's individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1457988065 · Glaucoma Specialist (Ophthalmology) Physician
NPI-10 · ENUM-RECENT · TAX-TRACE · RX-MID · BOOK-THIN · PHOTO-ENUM
- NPI-10 1457988065
- ENUM-RECENT 2020
- TAX-TRACE 383
- RX-MID 1,442
- BOOK-THIN 60 in California
- PHOTO-ENUM Anfei Li, MD · 2020
Robert Gunzenhauser, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
1,442 ≥ 80th percentile 80% of 1,416,883 prescribers are in lower value bands
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Robert Gunzenhauser, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Robert Gunzenhauser, MD?
Quality data not reportedPrimary specialty
Glaucoma Specialist (Ophthalmology) Physician
Medicare Part D claims
1,442 52% vs specialty avg
Specialty distribution in California
How Glaucoma Specialist (Ophthalmology) Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Glaucoma Specialist (Ophthalmology) Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Practice Address
Provider Details
| NPI | 1457988065 |
|---|---|
| Specialty | Glaucoma Specialist (Ophthalmology) Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 03/24/2020 |
Hospital and facility affiliations
Facilities where Robert Gunzenhauser, MD bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Marc H Shomer MD Phd Inc
Upland, CA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Robert Gunzenhauser, MD. Source: openpaymentsdata.cms.gov.
Total received
$325
Largest payer
Carl Zeiss Meditec USA, Inc.
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to Robert Gunzenhauser, MD. To verify Robert Gunzenhauser, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Above average
Robert Gunzenhauser, MD - brand share 39.0%
Glaucoma Specialist (Ophthalmology) Physician average
39% brand-name claims vs 61% generic, on 1,442 2024 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2024.
1,442
Total Claims
$131K
Total Drug Cost
598
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 2,535.8
- Total Day Supply
- 72,129
- Brand vs Generic
- 39% brand / 61% generic
- Brand Drug Cost
- $98K
- Generic Drug Cost
- $32K
Patient Demographics
- Average Patient Age
- 77.8 years
- Avg HCC Risk Score
- 1.37
- Gender Split
- 56% female / 44% male
- Age Distribution
- <65: 18, 65-74: 195, 75-84: 255, 85+: 130
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Robert Gunzenhauser, MD prescribes most
Top Medicare Part D drugs by claim count, 2024
- Latanoprost
Latanoprost
254 claims
- Brimonidine Tartrate
Brimonidine Tartrate
189 claims
- Dorzolamide-Timolol
Dorzolamide-Timolol
171 claims
- Prednisolone Acetate
Prednisolone Acetate
145 claims
- Timolol Maleate
Timolol Maleate
104 claims
- Ofloxacin 72
Ofloxacin
72 claims
- Brinzolamide 57
Brinzolamide
57 claims
- Ketorolac Trometha… 53
Ketorolac Tromethamine
53 claims
| Drug | Claims |
|---|---|
| Latanoprost | 254 |
| Brimonidine Tartrate | 189 |
| Dorzolamide-Timolol Dorzolamide Hcl/Timolol Maleat | 171 |
| Prednisolone Acetate | 145 |
| Timolol Maleate | 104 |
| Ofloxacin | 72 |
| Brinzolamide | 57 |
| Ketorolac Tromethamine | 53 |
| Dorzolamide Hcl | 50 |
| Rhopressa Netarsudil Mesylate | 40 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Glaucoma Specialist (Ophthalmology) Physician in CA →
All providers in California →
Compare specialties →
Glaucoma Specialist (Ophthalmology) Physician Overview
How Robert Gunzenhauser, MD fits within the Glaucoma Specialist (Ophthalmology) Physician landscape nationally.
383
Glaucoma Specialist (Ophthalmology) Physician Providers in US
42
States with Glaucoma Specialist (Ophthalmology) Physician
3,029
Avg Claims per Provider
Robert Gunzenhauser, MD's 1,442 claims are below the specialty average of 3,029.
Nationwide Glaucoma Specialist (Ophthalmology) Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Gunzenhauser, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2020)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Glaucoma Specialist (Ophthalmology) Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Gunzenhauser.
One of 60 Glaucoma Specialist (Ophthalmology) Physician providers enrolled in California, 5 are shown here.
Dr. Reza Alizadeh
M.D.
Santa Monica, CA
Dr. Ardalan Aminlari
MD
Encinitas, CA
Dr. Thomas Avallone
M.D.
Coronado, CA
Dr. Felise May Barte
MD
Santa Clara, CA
Dr. Sahar Bedrood
MD,PHD
Pasadena, CA
Compare Glaucoma Specialist (Ophthalmology) Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Robert Gunzenhauser, MD's specialty? ▼
Robert Gunzenhauser, MD specializes in Glaucoma Specialist (Ophthalmology) Physician and practices in Upland, California. Credentials: MD.
How much does Robert Gunzenhauser, MD prescribe under Medicare Part D? ▼
In 2024, Robert Gunzenhauser, MD wrote 1,442 Medicare Part D claims totaling $131K in drug costs for 598 beneficiaries.
Where is Robert Gunzenhauser, MD located? ▼
Robert Gunzenhauser, MD is located at 1298 W 7TH ST, Upland, CA, 91786. Phone: (909) 315-6891.
What is Robert Gunzenhauser, MD's NPI number? ▼
Robert Gunzenhauser, MD's National Provider Identifier (NPI) is 1457988065, issued on 03/24/2020.
Does Robert Gunzenhauser, MD prescribe more brand-name or generic drugs? ▼
Robert Gunzenhauser, MD's prescribing is 39% brand-name and 61% generic drugs by claim count, with $98K in brand drug costs.
How many Glaucoma Specialist (Ophthalmology) Physician providers are there in the US? ▼
There are 383 Glaucoma Specialist (Ophthalmology) Physician providers across 42 states in the US. The average Glaucoma Specialist (Ophthalmology) Physician provider writes 3,029 Medicare Part D claims per year.
What drugs does Robert Gunzenhauser, MD prescribe most often? ▼
Based on 2024 Medicare Part D data, Robert Gunzenhauser, MD's most frequently prescribed drugs include Latanoprost, Brimonidine Tartrate, Dorzolamide-Timolol. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Robert Gunzenhauser, MD accept Medicare? ▼
Robert Gunzenhauser, MD appears in CMS Medicare data with 1,442 Part D claims and 598 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Robert Gunzenhauser, MD's credentials? ▼
Robert Gunzenhauser, MD's NPI is 1457988065 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2024). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of August 2026 (NPPES) / 2024 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of August 2026.