Doctor profile · Federal record

Dr. Margaret Greven, M.D.

Ophthalmology Physician (CMS: Ophthalmology) · Winston Salem, NC

  • NPI 1821380874
  • Accepts Medicare
  • 15 yrs in practice
  • Female
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
Medical Center Blvd Dept of Ophthalmology
Winston Salem, NC 271573216
(336) 716-4091
Mailing address
Po Box 602658
Charlotte, NC 282602658

Credentials & registration

NPPES · NUCC
NPI registered
May 2011 — 15 yrs on file
Profile last updated
July 21, 2022
Year of graduation
2011 — 15 yrs since
Specialty taxonomy
207W00000X — NUCC code
State license (1)
North Carolina #2017-01126

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1821380874. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
2,738
Distinct HCPCS
10
Medicare allowed
$344,200
HCPCS Description Services Patients Avg allowed
92134 Imaging of retina 905 386 $23
67028 Injection of drug into eye 672 142 $98
99213 Established patient office or other outpatient visit, 20-29 minutes 362 274 $62
J0178 Injection, aflibercept, 1 mg 216 23 $865
67028 Injection of drug into eye 177 40 $118
92134 Imaging of retina 158 52 $38
J9035 Injection, bevacizumab, 10 mg 100 18 $71
99214 Established patient office or other outpatient visit, 30-39 minutes 70 59 $93
99213 Established patient office or other outpatient visit, 20-29 minutes 44 31 $84
99204 New patient office or other outpatient visit, 45-59 minutes 18 18 $127

In context: peer comparison

Among 13 peers in this city , average services per provider: 262. This provider delivers 10× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$438
Transactions
3
Manufacturers
2
Payer (manufacturer) Industry Txns Amount
Genentech, Inc. 2 $291.18
Regeneron Pharmaceuticals, Inc. 1 $146.88

By nature of payment

Food and Beverage
$438

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
247
Patients
127
Total drug cost
$9,249
Drug Type Claims Patients Total cost
Prednisolone Acetate Generic 109 77 $3,952
Dorzolamide-Timolol (Dorzolamide Hcl/Timolol Maleat) Brand 35 18 $864
Timolol Maleate Generic 30 18 $243
Brimonidine Tartrate Generic 28 14 $3,018
Latanoprost Generic 22 0 $82
Dorzolamide Hcl Generic 12 0 $590
Ketorolac Tromethamine Generic 11 0 $499

Frequently asked questions

Auto-generated from federal data
What is Dr. Margaret Greven's medical specialty?
Dr. Margaret Greven practices Ophthalmology Physician in Winston Salem, NC.
Where does Dr. Margaret Greven practice?
Dr. Margaret Greven practices at Medical Center Blvd Dept of Ophthalmology, Winston Salem, NC 271573216. Office phone: 3367164091.
What is Dr. Margaret Greven's NPI?
Dr. Margaret Greven's National Provider Identifier (NPI) is 1821380874, issued by NPPES.
Does Dr. Margaret Greven accept Medicare assignment?
Yes. Dr. Margaret Greven accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Margaret Greven commonly perform?
Top Medicare-reported procedures in 2023: Imaging of retina (HCPCS 92134); Injection of drug into eye (HCPCS 67028); Established patient office or other outpatient visit (HCPCS 99213). Source: CMS Medicare Physician & Other Practitioners file.