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DR. ROBERT CHOOLJIAN GUNZENHAUSER MD
NPI 1457988065
Ophthalmology in Upland, CA

Active since March 24, 2020PECOS EnrolledAccepts Medicare Assignment
1298 W 7TH ST, UPLAND, CA 91786(909) 315-6891(909) 946-3937 Get Directions Write a Review

NPPES record last updated: July 21, 2026. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Jul 21, 2026, Jul 1, 2024, Mar 24, 2020 (3 updates tracked since 2020).

About Dr. Robert Chooljian Gunzenhauser Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. ROBERT CHOOLJIAN GUNZENHAUSER MD (NPI 1457988065) is an individual ophthalmology provider in Upland, California, licensed in California (A189179) and active in the NPI registry since March 2020. He is enrolled in Medicare PECOS and is a graduate of Wake Forest University School Of Medicine (2020).

NPPES Registry Identity

NPI1457988065
Entity TypeIndividualMale
Primary Taxonomy207W00000X
Provider Legal NameDR. ROBERT CHOOLJIAN GUNZENHAUSERCredential: MD
Location Address1298 W 7TH STUpland, CA 91786-7035
Mailing AddressPo Box 1075Dana Point, CA 92629-5075 · (909) 315-6891 · Fax (909) 946-3937
Phone(909) 315-6891
Fax(909) 946-3937
Sole ProprietorNo
Medical School CMSWake Forest University School Of MedicineGraduated 2020
Enumeration DateMarch 24, 2020
Last NPPES UpdateJuly 21, 20263 updates tracked since enumeration
NPPES CertifiedJuly 21, 2026
✔ NPI 1457988065 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyOphthalmologyAllopathic & Osteopathic Physicians
Taxonomy Code207W00000X
License✔ Licensed in CA · A189179
Definition
An ophthalmologist has the knowledge and professional skills needed to provide comprehensive eye and vision care. Ophthalmologists are medically trained to diagnose, monitor and medically or surgically treat all ocular and visual disorders. This includes problems affecting the eye and its component structures, the eyelids, the orbit and the visual pathways. In so doing, an ophthalmologist prescribes vision services, including glasses and contact lenses.
Also ListedOphthalmology · Glaucoma SpecialistTaxonomy 207WX0009X · License A189179 (CA)
1298 W 7TH ST, Upland, CA 91786
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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Robert Chooljian Gunzenhauser Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID9931642923
PECOS Enrollment IDI20240618004054
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show Robert Gunzenhauser reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Marc H. Shomer, MD, Phd, Inc
Same address
Multi-Specialty
1298 W 7TH ST
Upland, CA 91786
  • Reassigned Medicare billing, California enrollment
  • 2 clinicians in this Medicare group
NPI 1427380070 (909) 981-9800

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 4

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214
This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.
74 services62 patients
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213
This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.
63 services58 patients
Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more 99212
This is a routine check-up for patients who have previously seen the doctor. During this 10-19 minute visit, the doctor will review your health status, discuss any concerns, and manage ongoing treatments or medications. It's a chance to ensure your health is on track.
53 services48 patients
Exam of the internal drainage system of eye 92020
This is a procedure where your doctor examines the eye's internal drainage system, essential for maintaining eye pressure. They use specialized tools to check for blockages or damage that might lead to conditions like glaucoma. It's non-invasive and painless.
15 services15 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 91786 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$136.04 typical visit price
range $59.60 – $179.42
Typical copayment $34.01 (range $14.90 – $44.85)
Most-billed visit code 99204
Established Patient
$74.08 typical visit price
range $19.37 – $146.42
Typical copayment $18.52 (range $4.84 – $36.60)
Most-billed visit code 99213
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 2

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

MARC H. SHOMER, MD, PHD, INC
Clinic/Center (Multi-Specialty)
1298 W 7TH ST
UPLAND, CA 91786
San Bernardino County (909) 981-9800
DR. MARC HOWARD SHOMER M.D., PH.D.
Ophthalmology
1298 W 7TH ST
UPLAND, CA 91786
San Bernardino County (909) 981-9800

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Robert Gunzenhauser's NPI number?

The NPI number for Robert Gunzenhauser is 1457988065. It was assigned to this individual provider in the NPPES registry on March 24, 2020.

Where is Robert Gunzenhauser located?

Robert Gunzenhauser practices at 1298 W 7th St, Upland, CA 91786. The listed phone number is (909) 315-6891.

What is Robert Gunzenhauser's specialty?

The primary specialty registered for this NPI is Ophthalmology with taxonomy code 207W00000X.

Is Robert Gunzenhauser enrolled in Medicare?

Yes. Robert Gunzenhauser is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for Robert Gunzenhauser's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Robert Gunzenhauser reassigns Medicare benefits to Marc H. Shomer, MD, Phd, Inc (Upland, CA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Robert Gunzenhauser's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Robert Gunzenhauser was last updated on July 21, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.