Robert Chooljian Gunzenhauser, MD

Primary specialty

Ophthalmology PhysicianTaxonomy code 207W00000X

License

A189179 Issued in CA

Practice address

1298 W 7TH St
Upland, CA 91786-7035

Phone

(909) 315-6891

Fax

(909) 946-3937

NPI assigned

Mar 24, 2020

Sex

Male

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Medicare fee-for-service enrollment

Enrolled in CA

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Ophthalmology

Education

Wake Forest University School of Medicine, 2020

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Marc H Shomer MD PHD IncGroup PAC ID 0547453888, 2 clinicians

Practice addresses (Care Compare)

Procedures performed for Medicare patients

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

Practice roles

Locations

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• Marc H. Shomer, MD, PHD, Inc

  • Multi-Specialty Clinic/Center
  • Upland, CA
  • NPI 1427380070
  Medicare reassignment Care Compare group NPD

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1585008000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1784592000000",
    "number": "1457988065",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 1075",
            "city": "DANA POINT",
            "state": "CA",
            "postal_code": "926295075",
            "telephone_number": "909-315-6891",
            "fax_number": "909-946-3937"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "1298 W 7TH ST",
            "city": "UPLAND",
            "state": "CA",
            "postal_code": "917867035",
            "telephone_number": "909-315-6891",
            "fax_number": "909-946-3937"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "GUNZENHAUSER",
        "first_name": "ROBERT",
        "middle_name": "CHOOLJIAN",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2020-03-24",
        "last_updated": "2026-07-21",
        "certification_date": "2026-07-21",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207WX0009X",
            "taxonomy_group": "",
            "desc": "Ophthalmology, Glaucoma Specialist",
            "state": "CA",
            "license": "A189179",
            "primary": false
        },
        {
            "code": "207W00000X",
            "taxonomy_group": "",
            "desc": "Ophthalmology",
            "state": "CA",
            "license": "A189179",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Angel Guillen
• Guillermo S, Castillo DDS Dental Corporation
• Marvin Guillory
• Lydia Guirges
• Golda Ariel Gultom
• Beiying Guo
• Naveen Gupta, M.D.
• Perry Thomas Guthrie, PH.D.
• Carla Mariela Gutierrez
• Diana Gutierrez

• Ophthalmology Physician in Upland, CA
• Providers in Upland, CA by specialty
• Ophthalmology Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jul 21, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.