What is William Mosier's specialty?

William Mosier (NPI 1063553378) is a Medicare-billing provider whose primary specialty is Ophthalmology in Fullerton, CA.

Where does William Mosier practice?

William Mosier practices in Fullerton, CA, based on the location reported in the CMS Medicare provider datasets for NPI 1063553378.

How much does Medicare pay William Mosier?

William Mosier (NPI 1063553378) received approximately $180K in total Medicare Part B payments, serving 905 beneficiaries, per the CMS Medicare Physician & Other Practitioners dataset.

PROVIDER PROFILE · NPI 1063553378

William MosierMD

PRACTICEWILLIAM D. MOSIER MDSee all providers at this practice →

OphthalmologyFullerton, CAI

MEDICARE UTILIZATION · PART B · 2024

Total beneficiaries

2,283

Unique beneficiaries

—

Total services

2,749

Distinct HCPCS

Medicare payment

$174K

Peer benchmark

Total Medicare services vs. 2,144 Ophthalmology providers in CA — above median (cohort median 1,859).

PRESCRIBING · PART D · 2024

Total Rx claims

4,419

Beneficiaries

—

Total drug cost

$482K

Distinct drugs

Brand share

32.5%

Top prescribed drugs

Latanoprost1,589 claims

Timolol Maleate632 claims

Dorzolamide Hcl/Timolol Maleat615 claims

Brimonidine Tartrate278 claims

Bimatoprost254 claims

QUALITY · MIPS · 2024

Final MIPS score

86.9

Quality

99.9

Cost

56.4

Improvement activities

40.0

Promoting interop.

0.0

Payment adjustment

0.50%

Group

INDUSTRY PAYMENTS · OPEN PAYMENTS · 2025

Total received

$873

Payment records

By payment type

Food and Beverage$873

Top paying entities

Food and Beverage$873

FACILITY AFFILIATIONS

Hospital & Facility Affiliations (1)

CCN 050168

Hospital

REFERRAL NETWORK

Where William Mosier's patients come from & go

Directional shared-patient flow from Medicare claims — who sends patients to this provider (inbound) and where this provider's patients go next (outbound). 19 inbound referrers · 48 outbound destinations.

Receives referrals from

Inbound — who sends patients here

Physician	Patients	Visits
Victor Lee Pathology · Oceanside, CA	195	463
ST JUDE HOSPITAL INC	192	388
Unilab Corporation Clinical Laboratory · West Hills, CA	61	129
Ramesh Rathod Interventional Cardiology · Fullerton, CA	29	58
UNGER, PHILLIP	19	27
Charles Suh Interventional Cardiology · Fullerton, CA	17	39
Eugene Byun Cardiology · Fullerton, CA	17	34
Daniel Landa Internal Medicine · Fullerton, CA	15	44
Bradley Borsari Internal Medicine · Fullerton, CA	14	65
Robert Rosenberg Dermatology · Fullerton, CA	14	24
Danh Nguyen Diagnostic Radiology · Riverside, CA	13	43
Sean Adrean Ophthalmology · Fullerton, CA	13	30

Refers patients to

Outbound — where patients go next

Physician	Patients	Visits
ST JUDE HOSPITAL INC	227	711
Victor Lee Pathology · Oceanside, CA	182	419
Unilab Corporation Clinical Laboratory · West Hills, CA	54	117
Quest Diagnostics Nichols Institute Clinical Laboratory · San Juan Capistrano, CA	32	82
Scott Grant Ophthalmology · Fullerton, CA	27	41
Eugene Byun Cardiology · Fullerton, CA	26	52
HANCOCK, JAMIE	26	33
Ramesh Rathod Interventional Cardiology · Fullerton, CA	25	48
Jay Han Cardiology · Fullerton, CA	23	48
Jesus Vera Interventional Cardiology · Fullerton, CA	22	39
John Kim Ophthalmology · Colton, CA	21	35
UNIVERSITY OF CALIFORNIA IRVINE	21	63

Source: CMS Physician Shared Patient Patterns (30-day window, Medicare FFS). Direction = a beneficiary seen by the first provider, then the second, within 30 days; a proxy for referral, not a documented referral. Pairs with fewer than 11 shared beneficiaries are suppressed.

CROSS-REFERENCE

Related data on other Healthparse brands

ProviderScore

OIG/SAM exclusion screening, sanctions history

Healthparse Signals

Monitor this provider for changes — dated NPI change events