Howard Guan, M.D.

Primary specialty

Glaucoma Specialist (Ophthalmology) PhysicianTaxonomy code 207WX0009X

License

A119766 Issued in CA

Practice address

340 Rancheros Drive
Suites 164/166
San Marcos, CA 92069

Phone

(760) 598-0400

Fax

(760) 290-7044

NPI assigned

Mar 7, 2011

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

Loma Linda University School of Medicine, 2010

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Tory Prestera MD Inc.Group PAC ID 0042594525, 2 clinicians

Practice addresses (Care Compare)

Merit-based Incentive Payment System (MIPS)

Final score

100 of 100Reported as group

Quality

100

Improvement activities

40

Cost

76.1

Merit-based Incentive Payment System (MIPS)

Final score

88.87 of 100Reported as group

Quality

72.13

Promoting interoperability

80

Improvement activities

40

Cost

77.36

Procedures performed for Medicare patients

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Networks

• BSC 65 PLUS INDIVIDUAL MAPD

Interoperability endpoints

• Direct secure messaging: hguan7372@direct.llu.edu

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.

• Tory Prestera MD Inc.

  • Ophthalmology Physician
  • San Marcos, CA
  • NPI 1073970687
  Medicare reassignment Care Compare group NPD
• Emergency and Acute Care Medical Corporation

  • Emergency Medicine Physician
  • San Diego, CA
  • NPI 1437103942
  Medicare reassignment NPD
• Faculty Physicians and Surgeons of Llusm

  • Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician
  • Apple Valley, CA
  • NPI 1205009917
  Medicare reassignment NPD
• RSF Ophthalmology, PC

  • Ophthalmology Physician
  • San Marcos, CA
  • NPI 1497466767
  Medicare reassignment NPD
• Faculty Physicians and Surgeons of Llusm

  • Ophthalmology Physician
  • Riverside, CA
  • NPI 1033361886
  NPD
• Faculty Physicians and Surgeons of Llusm

  • Ophthalmology Physician
  • Loma Linda, CA
  • NPI 1437109469
  NPD
• Faculty Physicians and Surgeons of Llusm

  • Family Medicine Physician
  • Moreno Valley, CA
  • NPI 1558788331
  NPD
• Faculty Physicians and Surgeons of Llusm

  • Orthopaedic Surgery Physician
  • Loma Linda, CA
  • NPI 1275582918
  NPD (past)
• Loma Linda University Children'S Hospital

  • Children's Hospital
  • Loma Linda, CA
  • NPI 1366866345
  NPD (past)
• Loma Linda University Medical Center

  • General Acute Care Hospital
  • Loma Linda, CA
  • NPI 1194731935
  NPD (past)
• Riverside Healthcare System, L.P.

  • Rehabilitation Hospital Unit
  • Riverside, CA
  • NPI 1053358010
  NPD (past)
• Tory Prestera MD PHD

  • Ophthalmology Physician
  • San Marcos, CA
  • NPI 1154761278
  NPD (past)

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

{
    "created_epoch": "1299456000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1761004800000",
    "number": "1134427636",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "340 RANCHEROS DRIVE",
            "address_2": "SUITES 164/166",
            "city": "SAN MARCOS",
            "state": "CA",
            "postal_code": "92069",
            "telephone_number": "760-598-0400",
            "fax_number": "760-290-7044"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "340 RANCHEROS DRIVE",
            "address_2": "SUITES 164/166",
            "city": "SAN MARCOS",
            "state": "CA",
            "postal_code": "92069",
            "telephone_number": "760-598-0400",
            "fax_number": "760-290-7044"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "GUAN",
        "first_name": "HOWARD",
        "credential": "M.D.",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2011-03-07",
        "last_updated": "2025-10-21",
        "certification_date": "2025-10-21",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207W00000X",
            "taxonomy_group": "",
            "desc": "Ophthalmology",
            "state": "CA",
            "license": "A119766",
            "primary": false
        },
        {
            "code": "207WX0009X",
            "taxonomy_group": "",
            "desc": "Ophthalmology, Glaucoma Specialist",
            "state": "CA",
            "license": "A119766",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Charlie Grenier, PPS, MS
• Vanessa Grimsley
• Hailey Groff
• Group Psychotherapy Services
• Amy Crotty Grumann, RN
• Stewart D Guentner, REGISTERED DIETITIAN
• Jazmine Guerra
• Juan Leon Guerrero
• Desiree Guevara
• Stephen Guffanti, M.D.

• Glaucoma Specialist (Ophthalmology) Physician in San Marcos, CA
• Providers in San Marcos, CA by specialty
• Glaucoma Specialist (Ophthalmology) Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Oct 21, 2025; 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.