John O'block, O.D.
John O'block, O.D. is a provider specialising in Optometrist in Derry, NH, registered under NPI 1427200724. 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 6 TSIENNETO ROAD SUITE 101, Derry, NH 03038. 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 |
|---|---|---|
| 0823 | NH | Optometrist primary |
This provider holds licence 0823 issued in NH. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Optometry
- PAC ID
- 4082778964
Medicare enrolment is recorded as approved under the provider type Practitioner - Optometry. This means the provider is enrolled to bill Medicare, though it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
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
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 | 1427200724 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Oct 17, 2008 |
| Last updated | May 7, 2014 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | O.D. |
| Practice address |
6 TSIENNETO ROAD SUITE 101 Derry, NH 03038 (603) 434-4193 Fax (603) 437-6804 |
| Mailing address |
6 TSIENNETO RD STE 101 Derry, NH 03038 |
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 | 4 | 2 | 7 | 2 | 0 | 0 | 7 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 4 | 4 | 7 | 4 | 0 | 0 | 7 | 4 |
Sum = 56 · next multiple of 10 = 60 · check digit = 4 · actual last digit = 4
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.