Oscar Chen, MD, MS
NPI 1598329989 · Ophthalmology Physician · Orange, CA
Enrolled with Medicare as Practitioner - Ophthalmology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Oscar Chen, MD, MS is a Ophthalmology Physician provider in Orange, CA (NPI 1598329989).
Provider details
- NPI number
- 1598329989
- Entity type
- Individual
- Primary specialty
- Ophthalmology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD, MS
- Sex
- Male
- Sole proprietor
- Yes
- License
- 125077452 (IL)
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 tenure33% of score
7 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
3 documented practice locations
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
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 methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 10 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Latanoprost | 218 | 79 |
| Prednisolone Acetate | 94 | 51 |
| Brimonidine Tartrate | 63 | 30 |
| Dorzolamide Hcl/Timolol Maleatbrand: Dorzolamide-Timolol | 58 | 28 |
| Timolol Maleate | 56 | 21 |
| Dorzolamide Hcl | 38 | 18 |
| Ketorolac Tromethamine | 19 | 13 |
| Atropine Sulfate |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$967 across 15 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
Additional practice locations (2)
- 1725 W Harrison St Ste 906Chicago, IL 60612-3848Phone: (312) 942-5000
- 600 S Paulina St Ste 403Chicago, IL 60612-3806Phone: (312) 942-7100
Registry dates
- Enumerated
- 2019-05-01
- Last updated
- 2025-06-04
- Certified
- 2025-06-04
Frequently asked questions
- What is Oscar Chen's NPI number?
- Oscar Chen's National Provider Identifier (NPI) is 1598329989, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Oscar Chen's specialty?
- Oscar Chen is listed in the NPPES registry with a primary specialty of Ophthalmology Physician (Allopathic & Osteopathic Physicians).
- Where is Oscar Chen located?
- Oscar Chen's practice location on file with NPPES is 101 the City Dr S, Orange, CA 92868-3201.
- What is Oscar Chen's phone number?
- The practice phone number listed in the NPPES registry for Oscar Chen is (949) 824-7105.
- Does Oscar Chen accept Medicare?
- Oscar Chen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Oscar Chen's NPI active?
- Yes — Oscar Chen's NPI (1598329989) is active in the NPPES registry as of the last update on 2025-06-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.