Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. John C Duff, O.D.

Optometrist in Brattleboro, VT · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1629033394

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Registry record

Entity type Individual (Type 1)

Name Dr. John C Duff

Credential O.D.

Sex Male

Practice address Brattleboro, VT, 05301

Phone (802) 254-6611

Fax (802) 258-4655

Enumeration date Apr 18, 2006

Last updated in NPPES Mar 27, 2014

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

152W00000X Optometrist Eye and Vision Services Providers · License 030000175 (VT) Primary

OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses. About the OD credential

Other identifiers

Identifier	Type	State	Issuer
0006601	Medicaid	VT	-
410003059	Other	VT	RAILROAD MEDICARE

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 → Validate an NPI →

Frequently asked questions

How do I verify John Duff's NPI record?

Cross-check NPI 1629033394 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1629033394 active?

Yes, as of the latest NPPES snapshot, NPI 1629033394 is active (record last updated 2014-03-27).

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2014-03-27.