Howard Guan, M.D.
NPI 1134427636 · Glaucoma Specialist (Ophthalmology) Physician · San Marcos, CA
Enrolled with Medicare as Practitioner - Ophthalmology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Howard Guan, M.D. is a Glaucoma Specialist (Ophthalmology) Physician provider in San Marcos, CA (NPI 1134427636).
Provider details
- NPI number
- 1134427636
- Entity type
- Individual
- Primary specialty
- Glaucoma Specialist (Ophthalmology) PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- A119766 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
15 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
2,701 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 615 | $17 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 370 | $137 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 273 | $97 |
| Photography of the Retina92250 | 241 | $40 |
| Imaging of Retina92134 | 225 | $44 |
| Imaging of Optic Nerve92133 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 28 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Latanoprost | 703 | 258 |
| Dorzolamide Hcl/Timolol Maleatbrand: Dorzolamide-Timolol | 308 | 121 |
| Brimonidine Tartrate | 290 | 103 |
| Prednisolone Acetate | 200 | 101 |
| Timolol Maleate | 197 | 82 |
| Diclofenac Sodium | 159 | 99 |
| Dorzolamide Hcl | 57 | 29 |
| Bimatoprostbrand: Lumigan |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$946 across 22 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2011-03-07
- Last updated
- 2025-10-21
- Certified
- 2025-10-21
Frequently asked questions
- What is Howard Guan's NPI number?
- Howard Guan's National Provider Identifier (NPI) is 1134427636, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Howard Guan's specialty?
- Howard Guan is listed in the NPPES registry with a primary specialty of Glaucoma Specialist (Ophthalmology) Physician (Allopathic & Osteopathic Physicians).
- Where is Howard Guan located?
- Howard Guan's practice location on file with NPPES is 340 Rancheros Drive, San Marcos, CA 92069.
- What is Howard Guan's phone number?
- The practice phone number listed in the NPPES registry for Howard Guan is (760) 598-0400.
- Does Howard Guan accept Medicare?
- Howard Guan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Howard Guan's NPI active?
- Yes — Howard Guan's NPI (1134427636) is active in the NPPES registry as of the last update on 2025-10-21.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.