Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Dr. Thom S Thomassen, MD

Individual provider Ophthalmology Physician · NPI 1407903180

Dr. Thom S Thomassen, MD is an Ophthalmology in Janesville, Wisconsin. Graduated from Duke University School of Medicine in 1977, 49 years ago. Practices with Mercy Health System Corporation, a 751-clinician group and accepts Medicare assignment. Licensed in Illinois and Wisconsin.

Years since qualifying
49
Trained at
Duke University School of Medicine
Licensed in
IL, WI
In the registry since
2007
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

3524 E Milwaukee St
Janesville, WI 53546-1626
Phone: (608) 756-7100
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Ophthalmology Physician (primary) Taxonomy 207W00000X · Licence 34177 (WI)
Ophthalmology Physician Taxonomy 207W00000X · Licence 036-092307 (IL)

Record details

NPI number1407903180
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJanuary 4, 2007
Last updated in NPPESSeptember 29, 2011

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyOPHTHALMOLOGY
Medical schoolDUKE UNIVERSITY SCHOOL OF MEDICINE
Graduated 1977 (49 years in practice)
Group practice Mercy Health System Corporation — 751 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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