NPI registry status
Active
2026 NPPES data Ophthalmology Physician NPI 1528594546
Verify on CMS → Alexander Chen
Ophthalmology Physician in Pasadena, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 22,388 in Ophthalmology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
9K
Medicare Part D claims · 2K beneficiaries · Ophthalmology Physician avg: 1K
Industry payments
$160.05
4 payments · CMS Open Payments (Sunshine Act)
What the federal data shows
Alexander Chen filed 9,123 Medicare Part D claims in 2024 as an Ophthalmology Physician in Pasadena, California.
- 9K
- Part D claims, 2024
- Likely
- board-certified (heuristic)
- ≥98th
- pct by Part D claim volume (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Federal trust snapshot
What official records show about Alexander Chen
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1528594546), first enumerated 05/11/2017.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 9,123 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- Reported
Industry payment transparency
$160.05 in reported industry payments (4 transfers) in 2024 under the federal Sunshine Act — disclosed transfers of value, not a quality rating.
Source: CMS Open Payments
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not Alexander Chen's individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1528594546 · Ophthalmology Physician
NPI-10 · ENUM-RECENT · TAX-MID · RX-MID · BOOK-LIGHT · PHOTO-ENUM
- NPI-10 1528594546
- ENUM-RECENT 2017
- TAX-MID 22K Ophthalmology Physician
- RX-MID 9,123
- BOOK-LIGHT 2,888 in California
- PHOTO-ENUM Jared Weed, MD · 2017
Alexander Chen's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
9,123 ≥ 98th percentile 98% of 1,416,883 prescribers are in lower value bands
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Alexander Chen practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Alexander Chen?
Quality data not reportedPrimary specialty
Ophthalmology Physician
Medicare Part D claims
9,123 6× vs specialty avg
Specialty distribution in California
How Ophthalmology Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Ophthalmology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Practice Address
Provider Details
| NPI | 1528594546 |
|---|---|
| Specialty | Ophthalmology Physician |
| Gender | Male |
| NPI Issued | 05/11/2017 |
Hospital and facility affiliations
Facilities where Alexander Chen bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Southern California Permanente Medical Group
Gardena, CA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Alexander Chen. Source: openpaymentsdata.cms.gov.
Total received
$160
Largest payer
ABBVIE INC.
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to Alexander Chen. To verify Alexander Chen's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2024.
9,123
Total Claims
$965K
Total Drug Cost
1,689
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 16,431.533
- Total Day Supply
- 466,382
- Generic Drug Cost
- $133K
Patient Demographics
- Average Patient Age
- 76.3 years
- Avg HCC Risk Score
- 1.62
- Gender Split
- 58% female / 42% male
- Age Distribution
- <65: 63, 65-74: 690, 75-84: 648, 85+: 288
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Alexander Chen prescribes most
Top Medicare Part D drugs by claim count, 2024
- Latanoprost
Latanoprost
3,103 claims
- Dorzolamide-Timolol 1,063
Dorzolamide-Timolol
1,063 claims
- Brimonidine Tartrate 1,039
Brimonidine Tartrate
1,039 claims
- Prednisolone Acetate 611
Prednisolone Acetate
611 claims
- Timolol Maleate 531
Timolol Maleate
531 claims
- Ketorolac Trometha… 400
Ketorolac Tromethamine
400 claims
- Ofloxacin 386
Ofloxacin
386 claims
- Lumigan 273
Lumigan
273 claims
| Drug | Claims |
|---|---|
| Latanoprost | 3,103 |
| Dorzolamide-Timolol Dorzolamide Hcl/Timolol Maleat | 1,063 |
| Brimonidine Tartrate | 1,039 |
| Prednisolone Acetate | 611 |
| Timolol Maleate | 531 |
| Ketorolac Tromethamine | 400 |
| Ofloxacin | 386 |
| Lumigan Bimatoprost | 273 |
| Rhopressa Netarsudil Mesylate | 217 |
| Erythromycin Erythromycin Base | 189 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Ophthalmology Physician Overview
How Alexander Chen fits within the Ophthalmology Physician landscape nationally.
22,388
Ophthalmology Physician Providers in US
56
States with Ophthalmology Physician
1,490
Avg Claims per Provider
Alexander Chen's 9,123 claims are above the specialty average of 1,490.
Nationwide Ophthalmology Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Chen, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2017)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Ophthalmology Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Chen.
One of 2,888 Ophthalmology Physician providers enrolled in California, 5 are shown here.
Dr. Sam Abbassi
MD, MS
West Hills, CA
Dr. Richard Abbott
M.D.
San Francisco, CA
Dr. Nizar Abdelfattah
MD
Pasadena, CA
Dr. Parastou Abedi
MD
Aliso Viejo, CA
Dr. Shahla Abedi
MD
Aliso Viejo, CA
Compare Ophthalmology Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Alexander Chen's specialty? ▼
Alexander Chen specializes in Ophthalmology Physician and practices in Pasadena, California.
How much does Alexander Chen prescribe under Medicare Part D? ▼
In 2024, Alexander Chen wrote 9,123 Medicare Part D claims totaling $965K in drug costs for 1,689 beneficiaries.
Where is Alexander Chen located? ▼
Alexander Chen is located at 100 E CALIFORNIA BLVD, Pasadena, CA, 91105. Phone: (800) 898-2020.
What is Alexander Chen's NPI number? ▼
Alexander Chen's National Provider Identifier (NPI) is 1528594546, issued on 05/11/2017.
How many Ophthalmology Physician providers are there in the US? ▼
There are 22,388 Ophthalmology Physician providers across 56 states in the US. The average Ophthalmology Physician provider writes 1,490 Medicare Part D claims per year.
What drugs does Alexander Chen prescribe most often? ▼
Based on 2024 Medicare Part D data, Alexander Chen's most frequently prescribed drugs include Latanoprost, Dorzolamide-Timolol, Brimonidine Tartrate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Alexander Chen accept Medicare? ▼
Alexander Chen appears in CMS Medicare data with 9,123 Part D claims and 1,689 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Alexander Chen's credentials? ▼
Alexander Chen's NPI is 1528594546. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2024). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of August 2026 (NPPES) / 2024 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of August 2026.