Dr. Mark Tony Williams, M.D.
Dr. Mark Tony Williams is a Retina Specialist (Ophthalmology) Physician provider (Ophthalmology) practicing in Orange, CA, registered in the NPPES registry with NPI 1780118802 since 2017. The credential MD stands for Doctor of Medicine. Practices at Retina Specialists of Orange County, Inc. (listed at the same practice address in NPPES).
✓ Active NPI ✓ Valid NPI checksum Sole proprietor
| NPI | 1780118802 |
|---|---|
| Entity type | Individual (Type 1) |
| Name | Dr. Mark Tony Williams |
| Credential | M.D. |
| Sex | Male |
| Practice address | Orange, CA, 92868 |
| Phone | 7147384621 |
| Fax | 7144090629 |
| Enumeration date | 2017-04-14 |
| Last updated in NPPES | 2025-03-11 |
Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.
Taxonomy & licenses
| Taxonomy code | Specialty | Primary | License | State |
|---|---|---|---|---|
| 207W00000X | Ophthalmology Physician | Secondary | A187615 | CA |
| 207WX0107X | Retina Specialist (Ophthalmology) Physician | Primary | A187615 | CA |
MD — Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential
Copy-ready billing details
Provider: Mark Williams, M.D. NPI: 1780118802 Taxonomy: 207WX0107X (Retina Specialist (Ophthalmology) Physician) Address: Orange, CA, 92868
Other providers at this practice address
| NPI | Name | Type | Specialty | Location |
|---|---|---|---|---|
| 1629897517 | Retina Specialists of Orange County, Inc. | Organization | Retina Specialist (Ophthalmology) Physician | Orange, CA |
Verify this record
Cross-check NPI 1780118802 against the authoritative CMS record: view Dr. Mark Tony Williams on the official NPPES registry .
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes — even if the provider moves or changes specialty. Read the full guide or validate an NPI number.
Frequently asked questions
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Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2025-03-11.