John F. Warren, MD
NPI 1386634400ActiveIndividual· Ophthalmology· Greenfield, MA
Ophthalmology (MD) in Greenfield, Massachusetts, trained at Stanford University School of Medicine (class of 1997). In 2024 Medicare paid $512,534 for 883 patients, and Part D covered 2,695 of their prescriptions, 74% of them generic. Glaukos Corporation was the largest of 11 companies reporting payments in 2025, $828.41 in all, mostly food and beverage.
Overview
| NPI | 1386634400 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Oct 28, 2005 |
| Last updated in NPPES | Mar 7, 2023 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Ophthalmology Primary | 207W00000X | 223233 | MA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Ophthalmology (MA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 883 |
|---|---|
| Services billed | 3,992 across 42 procedure codes |
| Paid by Medicare | $512,534 |
Part D prescriptions in 2024
| Prescriptions (claims) | 2,695 · 3,852 30-day fills |
|---|---|
| Patients | 1,067 |
| Total drug cost | $288,581 |
| Generic share | 74% of claims |
Education and affiliations
| Medical school | Stanford University School of Medicine |
|---|---|
| Graduation year | 1997 |
| Medicare specialty | Ophthalmology |
Medical group
- Longwood Eye LLCWest Springfield, MA · 16 clinicians
Hospital affiliation
- Baystate Franklin Medical CenterGreenfield, MA
Industry payments (Open Payments)
- 2025$828.41 · 27 payments from 11 companies
- 2024$1,237 · 23 payments from 11 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Glaukos Corporation | $265.16 | 1 |
| Dompe US, Inc. | $161.31 | 7 |
| Ocular Therapeutix, Inc. | $109.34 | 6 |
| Abbvie Inc. | $75.52 | 3 |
| Sun Pharmaceutical Industries Inc. | $54.64 | 3 |
What the 2025 payments were for
- Food and Beverage$828.41 · 27 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
Other Ophthalmology providers in Greenfield
- 1588859490
- 1235303488
- 1013942002