William D. Mosier, MD
NPI 1063553378ActiveIndividual· Ophthalmology· Fullerton, CA
Ophthalmology (MD) in Fullerton, California, trained at University of California, Irvine, California College of Medicine (class of 1983). Their prescriptions cost Medicare Part D more than their services did: $514,210 for 4,503 claims, against $180,498 paid for services in 2024. Sun Pharmaceutical Industries Inc. was the largest of 9 companies reporting payments in 2025, $872.79 in all, mostly food and beverage.
Overview
| NPI | 1063553378 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | Yes |
| NPI issued | Feb 9, 2007 |
| Last updated in NPPES | Apr 11, 2014 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Ophthalmology Primary | 207W00000X | A41428 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Ophthalmology (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 905 |
|---|---|
| Services billed | 2,774 across 18 procedure codes |
| Paid by Medicare | $180,498 |
Part D prescriptions in 2024
| Prescriptions (claims) | 4,503 · 10,341 30-day fills |
|---|---|
| Patients | 957 |
| Total drug cost | $514,210 |
| Generic share | 55% of claims |
Education and affiliations
| Medical school | University of California, Irvine, California College of Medicine |
|---|---|
| Graduation year | 1983 |
| Medicare specialty | Ophthalmology |
Medical group
- William D Mosier MD Inc A Professional Medical CorporationFullerton, CA · 3 clinicians
Hospital affiliation
- Providence St. Jude Medical CenterFullerton, CA
Industry payments (Open Payments)
- 2025$872.79 · 37 payments from 9 companies
- 2024$917.37 · 50 payments from 9 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Sun Pharmaceutical Industries Inc. | $236.57 | 13 |
| Abbvie Inc. | $130.57 | 5 |
| Dompe US, Inc. | $124.51 | 5 |
| Amgen Inc. | $91.98 | 4 |
| Tarsus Pharmaceuticals, Inc. | $77.84 | 2 |
What the 2025 payments were for
- Food and Beverage$872.79 · 37 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 28 ophthalmologists in Fullerton · All ophthalmologists in California