JOANN CHANG, M.D. appears in the CMS NPPES registry as a Ophthalmology Physician provider holding M.D. credentials at 479 OLD UNION TPKE, LANCASTER, MA, 01523, with a listed phone of (978) 537-3900. NPI 1730359100 was issued on 03/02/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CHANG 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 1,841 prescription claims written by this provider, covering 620 Medicare beneficiaries and totaling roughly $817K in drug spend, split 65% brand-name and 35% 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 97.0218/100 for the 2023 performance year (Quality 78.0983), compared with the national average of 83.1.

Ophthalmology Physician is a mid-sized specialty nationwide, with 22,090 enrolled providers across 56 states and an average of 1,420 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.