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. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what LARSON most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

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. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 85.2409/100 for the 2023 performance year (Quality 97.9147, Cost 52.8883), compared with the national average of 83.1.

Glaucoma Specialist (Ophthalmology) Physician is a narrow specialty nationwide, with 354 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.