William Callahan, O.D.
NPI 1568536357 · Optometrist · Marshfield, MA
Enrolled with Medicare as Practitioner - Optometry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Callahan, O.D. is a Optometrist provider in Marshfield, MA (NPI 1568536357).
Provider details
- NPI number
- 1568536357
- Entity type
- Individual
- Primary specialty
- OptometristEye and Vision Services Providers
- Credential
- O.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 3071 (MA)
Specialties & taxonomies
Eye and Vision Services Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
563 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. 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 does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Problem Focused Exam of Visual System92012 | 196 | $91 |
| Photography of the Retina92250 | 118 | $37 |
| Exam of Visual Field With Extended Testing92083 | 92 | $65 |
| Established Patient Complete Exam of Visual System92014 | 86 | $128 |
| Photography of Content of Eyes92285 | 48 | $24 |
| New Patient Complete Exam of Visual System92004 | 23 | $152 |
Typical Medicare-allowed amounts for these services range $24–$152 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 1 distinct drug on file.
| Drug | Part D claims (2024) |
|---|---|
| Cyclosporinebrand: Restasis | 12 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-11-20
- Last updated
- 2012-08-23
Frequently asked questions
- What is William Callahan's NPI number?
- William Callahan's National Provider Identifier (NPI) is 1568536357, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Callahan's specialty?
- William Callahan is listed in the NPPES registry with a primary specialty of Optometrist (Eye and Vision Services Providers).
- Where is William Callahan located?
- William Callahan's practice location on file with NPPES is 462 Plain St, Marshfield, MA 02050-2731.
- What is William Callahan's phone number?
- The practice phone number listed in the NPPES registry for William Callahan is (781) 837-9956.
- Does William Callahan accept Medicare?
- William Callahan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Callahan's NPI active?
- Yes — William Callahan's NPI (1568536357) is active in the NPPES registry as of the last update on 2012-08-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.