NPI registry status
Active
2026 NPPES data Glaucoma Specialist (Ophthalmology) Physician NPI 1831651868 MD
Verify on CMS → Mark Larson, MD
Glaucoma Specialist (Ophthalmology) Physician in Greenfield, Wisconsin.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 356 in Glaucoma Specialist (Ophthalmology) Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
850
Medicare Part D claims · 253 beneficiaries · Glaucoma Specialist (Ophthalmology) Physician avg: 3K
Generic prescribing
58%
generic claims · 42% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
85.2/100
▲ 2 pts above national avg 83.1 · Above neutral
Industry payments
$288.25
7 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Mark Larson, MD reported a CMS MIPS final score of 85.2/100 - above the 83.1 national average - and filed 850 Medicare Part D claims in 2023.
- 85.2/100
- MIPS score · +2 vs avg
- 850
- Part D claims, 2023
- 58%
- generic prescribing
- Likely
- board-certified (heuristic)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Mark Larson, MD's MIPS score vs every scored U.S. clinician
CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure
85 49th percentile higher than 49% of 477,587 scored providers
Each bar is a band; taller bars hold more scored providers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Merit-based Incentive Payment System (MIPS) · 2023
Where Mark Larson, MD sits
This provider among glaucoma specialist (ophthalmology) physician peers
Across the 216 glaucoma specialist (ophthalmology) physician providers who report both Medicare Part D prescribing and a MIPS quality score, Mark Larson, MD writes more Part D claims than 11% of them and scores higher on MIPS quality than 42% - placing this provider in the lower-volume, lower-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.
Part D claim volume vs MIPS quality, by specialty percentile
Each dot is one glaucoma specialist (ophthalmology) physician peer from a representative sample of 60; the gold marker is Mark Larson, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.
✓
Board certification likely (heuristic, not verified)
Mark Larson, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Mark Larson, MD?
High performer (top quartile)Primary specialty
Glaucoma Specialist (Ophthalmology) Physician
Medicare Part D claims
850 71% vs specialty avg
MIPS final score
85.2/100 2.1 pts vs avg
Specialty distribution in Wisconsin
How Glaucoma Specialist (Ophthalmology) Physician compares to other specialties among Wisconsin providers
Medicare quality performance, MIPS
Mark Larson, MD's 2023 MIPS final score plotted against the Glaucoma Specialist (Ophthalmology) Physician national average
- MIPS Final Score
- 85.2/100
- vs 83.1 national avg · 2023 performance year
MIPS final score (Glaucoma Specialist (Ophthalmology) Physician) - 85.2/100 vs national avg 83.1
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Mark Larson, MD appears in the CMS NPPES registry as a Glaucoma Specialist (Ophthalmology) Physician provider holding MD credentials at 4600 W LOOMIS RD STE 310, Greenfield, WI, 53220, with a listed phone of (414) 281-0424. NPI 1831651868 was issued on 03/31/2019.
Medicare Part D records for calendar year 2023 show 850 prescription claims written by this provider, covering 253 Medicare beneficiaries and totaling roughly $77K in drug spend, split 42% brand-name and 58% generic by claim count. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 85.2/100 for the 2023 performance year (Quality 97.9, Cost 52.9), compared with the national average of 83.1.
Glaucoma Specialist (Ophthalmology) Physician is a narrow specialty nationwide, with 356 enrolled providers across 42 states and an average of 2,962 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1831651868 |
|---|---|
| Specialty | Glaucoma Specialist (Ophthalmology) Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 03/31/2019 |
CMS Quality Score (MIPS)
Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.
85.2409
Final Score
Avg: 83.1
97.9147
Quality
52.8883
Cost
100
Promoting Interoperability
Reporting: Group practice
Hospital and facility affiliations
Facilities where Mark Larson, MD bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Ophthalmology Associates S C
Greenfield, WI
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Mark Larson, MD. Source: openpaymentsdata.cms.gov.
Total received
$288
Largest payer
Amgen Inc.
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
Brand vs generic prescribing mix · Above average
Mark Larson, MD - brand share 42.0%
Glaucoma Specialist (Ophthalmology) Physician average
42% brand-name claims vs 58% generic, on 850 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
850
Total Claims
$77K
Total Drug Cost
253
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,212
- Total Day Supply
- 32,202
- Brand vs Generic
- 42% brand / 58% generic
- Brand Drug Cost
- $59K
- Generic Drug Cost
- $19K
Patient Demographics
- Average Patient Age
- 71.9 years
- Avg HCC Risk Score
- 1.64
- Gender Split
- 53% female / 47% male
- Age Distribution
- <65: 39, 65-74: 117, 75-84: 72, 85+: 25
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Mark Larson, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Latanoprost
Latanoprost
235 claims
- Prednisolone Acetate
Prednisolone Acetate
126 claims
- Ketorolac Trometha… 51
Ketorolac Tromethamine
51 claims
- Dorzolamide-Timolol 50
Dorzolamide-Timolol
50 claims
- Ofloxacin 47
Ofloxacin
47 claims
- Brimonidine Tartrate 44
Brimonidine Tartrate
44 claims
- Timolol Maleate 43
Timolol Maleate
43 claims
- Moxifloxacin 27
Moxifloxacin
27 claims
| Drug | Claims |
|---|---|
| Latanoprost | 235 |
| Prednisolone Acetate | 126 |
| Ketorolac Tromethamine | 51 |
| Dorzolamide-Timolol Dorzolamide Hcl/Timolol Maleat | 50 |
| Ofloxacin | 47 |
| Brimonidine Tartrate | 44 |
| Timolol Maleate | 43 |
| Moxifloxacin Moxifloxacin Hcl | 27 |
| Erythromycin Erythromycin Base | 25 |
| Gatifloxacin | 23 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Glaucoma Specialist (Ophthalmology) Physician in WI →
All providers in Wisconsin →
Compare specialties →
Glaucoma Specialist (Ophthalmology) Physician Overview
How Mark Larson, MD fits within the Glaucoma Specialist (Ophthalmology) Physician landscape nationally.
356
Glaucoma Specialist (Ophthalmology) Physician Providers in US
42
States with Glaucoma Specialist (Ophthalmology) Physician
2,962
Avg Claims per Provider
Mark Larson, MD's 850 claims are below the specialty average of 2,962.
Nearby Glaucoma Specialist (Ophthalmology) Physician Providers in Wisconsin
Other clinicians with the same primary specialty enrolled in Wisconsin, drawn from the same CMS NPPES roster as Larson.
Dr. Nicholas Frame
M.D.
Milwaukee, WI
Dr. Christiana Gandy
M.D.
Wausau, WI
Dr. Silvia Lara-Moses
MD, PA
Milwaukee, WI
Compare Glaucoma Specialist (Ophthalmology) Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Wisconsin medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Glaucoma Specialist (Ophthalmology) Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Mark Larson, MD's specialty? ▼
Mark Larson, MD specializes in Glaucoma Specialist (Ophthalmology) Physician and practices in Greenfield, Wisconsin. Credentials: MD.
How much does Mark Larson, MD prescribe under Medicare Part D? ▼
In 2023, Mark Larson, MD wrote 850 Medicare Part D claims totaling $77K in drug costs for 253 beneficiaries.
What is Mark Larson, MD's Medicare quality score? ▼
Mark Larson, MD has a CMS MIPS Final Score of 85.2/100 (Quality: 97.9, Cost: 52.9). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Mark Larson, MD located? ▼
Mark Larson, MD is located at 4600 W LOOMIS RD STE 310, Greenfield, WI, 53220. Phone: (414) 281-0424.
What is Mark Larson, MD's NPI number? ▼
Mark Larson, MD's National Provider Identifier (NPI) is 1831651868, issued on 03/31/2019.
Does Mark Larson, MD prescribe more brand-name or generic drugs? ▼
Mark Larson, MD's prescribing is 42% brand-name and 58% generic drugs by claim count, with $59K in brand drug costs.
How many Glaucoma Specialist (Ophthalmology) Physician providers are there in the US? ▼
There are 356 Glaucoma Specialist (Ophthalmology) Physician providers across 42 states in the US. The average Glaucoma Specialist (Ophthalmology) Physician provider writes 2,962 Medicare Part D claims per year.
What drugs does Mark Larson, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Mark Larson, MD's most frequently prescribed drugs include Latanoprost, Prednisolone Acetate, Ketorolac Tromethamine. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Mark Larson, MD accept Medicare? ▼
Mark Larson, MD appears in CMS Medicare data with 850 Part D claims and 253 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Mark Larson, MD's credentials? ▼
Mark Larson, MD's NPI is 1831651868 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Quality Performance
- CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.