Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Jon M Williamson, OD

Individual provider Optometrist · NPI 1932104114

Jon M Williamson, OD is registered under Optometry in Sparta, Wisconsin. Graduated from Illinois College of Optometry at Chicago in 1985, 41 years ago. Practices with Gundersen Clinic Ltd, a 427-clinician group and accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
41
Trained at
Illinois College of Optometry at Chicago
Licensed in
WI
In the registry since
2005
What do these letters mean?
OD — Doctor of Optometry
An optometrist: examines eyes, prescribes glasses and contacts, and treats many eye conditions.

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Practice location Address checks out

1111 W Wisconsin St
Sparta, WI 54656-2233
Phone: (608) 269-6731
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Directions in Google Maps · Apple Maps · OpenStreetMap

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

Specialties & licences

Optometrist (primary) Taxonomy 152W00000X · Licence 2115 (WI)

Record details

NPI number1932104114
Entity typeIndividual (Type 1)
GenderMale
Credentials OD
Sole proprietorNo
NPI enumeratedJune 15, 2005
Last updated in NPPESJuly 21, 2022

Medicare enrollment

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

Medicare specialtyOPTOMETRY
Medical schoolILLINOIS COLLEGE OF OPTOMETRY AT CHICAGO
Graduated 1985 (41 years in practice)
Group practice Gundersen Clinic Ltd — 427 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Cataract surgery 20 times · 45th percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients368
Services billed 3,629 a service is one billed item, such as a visit, a test or a procedure
Average patient age73

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Colleagues at Gundersen Clinic Ltd

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 427 clinicians in the practice; 12 are shown here.

Other providers in Sparta