Howard Guan, M.D.
Glaucoma Specialist (Ophthalmology) Physician · San Marcos, CA
Howard Guan, M.D. is a glaucoma specialist (ophthalmology) physician with a practice address in San Marcos, California, and NPI 1134427636, issued on Mar 7, 2011. Check the license (California A119766, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Howard Guan
- Credential
- M.D.
- Primary taxonomy
- Glaucoma Specialist (Ophthalmology) Physician 207WX0009X
- License number
- A119766 CA
Self-reported in NPPES; status is on the state search - Practice location
- 340 Rancheros Drive, San Marcos, CA 92069
- Phone
- (760) 598-0400
- Enumerated
- Mar 7, 2011
- Record last updated
- Oct 21, 2025
- Fax
- (760) 290-7044
- Medicare enrollment
- Enrolled (PECOS I20150724011344); accepts Medicare assignment
- Medical or professional school
- Loma Linda University School Of Medicine, 2010
- Entity
- Type 1 · individual
8 nearest glaucoma specialist (ophthalmology) physician records → All 70 in California → Look up another NPI →
Also registered at 340 Rancheros Drive
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Tory Prestera, MD.PHDOphthalmology Physician1346224557
Verify Howard Guan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A119766Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
15% fewer Medicare Part D claims than the average glaucoma specialist (ophthalmology) physician in 2024
2,586 Medicare Part D claims for 671 beneficiaries, against an average of 3,060 among the 430 providers of this specialty who prescribed in Part D. Brand-name drugs were 37% of claims.
Most prescribed
- Latanoprost703 claims
- Dorzolamide-Timolol308 claims
- Brimonidine Tartrate290 claims
- Prednisolone Acetate200 claims
- Timolol Maleate197 claims
- Diclofenac Sodium159 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
The practice group's MIPS final score for 2023 (Medicare payment program): 85.2 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $946.06
22 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 391 providers of this specialty with any payment received $5,284.60 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Tory Prestera MD Inc.San Marcos, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Howard Guan among 70 glaucoma specialist (ophthalmology) physician records in California
Howard Guan, M.D. is one of 70 glaucoma specialist (ophthalmology) physician records with a practice address in California. 97% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2011, is newer than 33% of them.
- NPI issued2011 · 33% of these records are older, 63% newer
- In a Medicare fileYes · 97% of these records are
- In the CMS Doctors and Clinicians fileYes · 93% of these records are
- Graduated2010 · median 2013 among the 65 with a school on file
- Record last updated2025 · 30% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207WX0009X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Glaucoma Specialist (Ophthalmology) Physician providers in California
There are 70 glaucoma specialist (ophthalmology) physician records in California.
All 70 in California → Every provider in San Marcos → Glaucoma Specialist (Ophthalmology) Physician nationwide →
The 8 glaucoma specialist (ophthalmology) physician records with the nearest ZIP codes
- Jiun Do, M.D., PH.D.La Jolla, CA 920931578900205
- Ashkan Kashanchi, MDSan Diego, CA 921031811576549
- Fahad Khan, MDSan Diego, CA 921031548605843
- Cristiana Vasile, M.D.San Diego, CA 921031891002044
- Ardalan Aminlari, MDEncinitas, CA 920241639497258
- Ann Lopez, M.D.San Diego, CA 921231750391231
- Andrew Camp, MDSan Diego, CA 921281326300377
- Luke Barnard, MDLa Mesa, CA 919421710543111
Common questions
What is Howard Guan, M.D.'s NPI number?
Howard Guan, M.D.'s National Provider Identifier (NPI) is 1134427636, issued on Mar 7, 2011. An NPI identifies a provider in billing; it is not a license.
Where is Howard Guan, M.D. located?
The NPPES record lists a practice address at 340 Rancheros Drive, San Marcos, CA, 92069. Phone: (760) 598-0400. Providers update this record themselves, so call before visiting.
How can I verify Howard Guan, M.D.'s license?
NPPES lists California license number A119766, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Howard Guan, M.D. prescribe under Medicare Part D?
In 2024, Howard Guan, M.D. had 2,586 Medicare Part D claims for 671 beneficiaries; the average among glaucoma specialist (ophthalmology) physician prescribers was 3,060. Part D covers Medicare prescriptions only.
What is Howard Guan, M.D.'s MIPS final score?
The 2023 MIPS final score is 85.2 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.