Sean Gretz, OD
Sean Gretz, OD is a provider specialising in Optometrist in Easton, MD, registered under NPI 1720565641. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 210 MARLBORO AVE STE 31, Easton, MD 21601. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| TA3006 | MD | Optometrist primary |
| OEG003439 | PA | Optometrist |
| I3-0001417 | DE | Optometrist |
Licences are recorded in 3 states: MD, PA, DE. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Optometry
- PAC ID
- 0143578260
Enrolled in Medicare 2 times, across 2 states:
| State | Enrollment ID | Provider type |
|---|---|---|
| Delaware | I20200309000076 | Practitioner - Optometry |
| Maryland | I20240723000326 | Practitioner - Optometry |
Medicare enrolment is recorded as approved under the provider type Practitioner - Optometry. There are 2 separate enrolment records across 2 states (DE, MD). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 3 states
This provider holds licences in 3 states: Delaware, Maryland and Pennsylvania. The practice address on file is in Easton, MD, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Optometrist covers
Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. An optometrist has completed pre-professional undergraduate education in a college or university and four years of professional education at a college of optometry, leading to the doctor of optometry (O.D.) degree. Some optometrists complete an optional residency in a specific area of practice. Optometrists are eye health care professionals state-licensed to diagnose and treat diseases and disorders of the eye and visual system. NUCC Health Care Provider Taxonomy, code 152W00000X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 152W00000X | Optometrist | TA3006 | MD | primary |
| 152W00000X | Optometrist | OEG003439 | PA | |
| 152W00000X | Optometrist | I3-0001417 | DE |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1720565641 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 24, 2018 |
| Last updated | Jun 27, 2024 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | OD |
| Practice address |
210 MARLBORO AVE STE 31 Easton, MD 21601 (410) 822-3937 Fax (410) 822-2652 |
| Mailing address |
8614 WESTWOOD CENTER DR FL 9 Vienna, VA 22182 |
| Other identifiers |
OEG003439
· Other (PA) I3-0001417 · Other (DE) |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 7 | 2 | 0 | 5 | 6 | 5 | 6 | 4 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 7 | 4 | 0 | 1 | 6 | 1 | 6 | 8 |
Sum = 59 · next multiple of 10 = 60 · check digit = 1 · actual last digit = 1
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.