Physician Profile
Unclaimed ProfileAbout WARREN
Based in Greenfield, MA, John F Warren, MD is listed in the NPI registry under ophthalmology. John graduated from Stanford University School of Medicine in 1997.
Summarised automatically from public NPI registry and CMS Medicare data. Not written or reviewed by this provider. Claim this profile to replace it.
Education & Training
Areas of Expertise
Common questions
What kind of doctor is Dr. Warren?
Dr. Warren is an ophthalmology in Greenfield, MA. This is the primary taxonomy recorded against the NPI in the federal registry, listed there as “OPHTHALMOLOGY”.
NPI registry
What is Dr. Warren's address?
Dr. Warren is listed at 33 RIDDELL ST, Greenfield, MA 01301. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Dr. Warren?
The number on file is (413) 774-7016. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Warren's NPI number?
Dr. Warren's National Provider Identifier is 1386634400. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Dr. Warren train?
Dr. Warren attended Stanford University School of Medicine, graduating in 1997. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Warren been practising?
Dr. Warren has 29 years experience. Calculated from a graduation year of 1997, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Warren perform?
According to Medicare billing data, Dr. Warren performs procedures including removal of cataract with insertion of prosthetic lens, insertion of drug delivery implant into tear duct of eye and removal of recurring cataract in lens capsule using a laser; provides treatments such as measurement of corneal curvature and depth of eye and imaging of retina, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Warren confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Warren. If this is you, claiming it is free.
Guide.md
Licensing & Certification
Source: NPPES NPI Registry
Contact Information
- (413) 774-7016
- Email not available
Practice Locations
33 RIDDELL ST
Greenfield, MA 01301
Procedures Most Often Billed to Medicare
3,913 services · 2,714 patients · 15 distinct codes
| Procedure | Type | Code | Services |
|---|---|---|---|
| Removal of cataract with insertion of prosthetic lens | Procedure | 66984 |
619 |
| Insertion of drug delivery implant into tear duct of eye | Procedure | 68841 |
213 |
| Removal of recurring cataract in lens capsule using a laser | Procedure | 66821 |
72 |
| Extracapsular removal of cataract with insertion of artificial lens and insertion of drainage device in front chamber of eye | Procedure | 66991 |
45 |
| Complex removal of cataract with insertion of prosthetic lens | Procedure | 66982 |
40 |
| Measurement of corneal curvature and depth of eye | Treatment | 92136 |
987 |
| Imaging of retina | Treatment | 92134 |
542 |
| Established patient complete exam of visual system | Treatment | 92014 |
538 |
| Ct scan of cornea | Treatment | 92025 |
333 |
| Established patient problem focused exam of visual system | Treatment | 92012 |
136 |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
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Claim this profileRelated providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Related specialists at this location 1
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
Other ophthalmology specialists in Greenfield 3
Same specialty, same city.
More connections — 24 related providers in 3 groups
Trained at Stanford University School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1997 at Stanford University School of Medicine 8
Providers who graduated from the same medical school in the same year.
Also performs Removal of cataract with insertion of prosthetic lens 8
Providers in MA who bill this service to Medicare most often.
Provider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.