Greta Gregg
NPI 1134787559 · Optometrist · Chicago, IL
Enrolled with Medicare as Practitioner - Optometry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Greta Gregg is a Optometrist provider in Chicago, IL (NPI 1134787559).
Provider details
- NPI number
- 1134787559
- Entity type
- Individual
- Primary specialty
- OptometristEye and Vision Services Providers
- Sex
- Female
- Sole proprietor
- No
- License
- 046011305 (IL)
Specialties & taxonomies
Eye and Vision Services Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
7 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
140 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 83 | $94 |
| Exam of Visual Field With Extended Testing92083 | 31 | $64 |
| Imaging of Optic Nerve92133 | 14 | $36 |
| Photography of the Retina92250 | 12 | $36 |
Typical Medicare-allowed amounts for these services range $36–$94 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 4 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Latanoprost | 117 | 37 |
| Dorzolamide Hcl/Timolol Maleatbrand: Dorzolamide-Timolol | 54 | 16 |
| Brimonidine Tartrate | 32 | — |
| Bimatoprostbrand: Lumigan | 13 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$121 across 2 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2019-05-31
- Last updated
- 2019-06-04
Frequently asked questions
- What is Greta Gregg's NPI number?
- Greta Gregg's National Provider Identifier (NPI) is 1134787559, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Greta Gregg's specialty?
- Greta Gregg is listed in the NPPES registry with a primary specialty of Optometrist (Eye and Vision Services Providers).
- Where is Greta Gregg located?
- Greta Gregg's practice location on file with NPPES is 3241 S Michigan Ave, Chicago, IL 60616-4201.
- What is Greta Gregg's phone number?
- The practice phone number listed in the NPPES registry for Greta Gregg is (312) 949-7751.
- Does Greta Gregg accept Medicare?
- Greta Gregg is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Greta Gregg's NPI active?
- Yes — Greta Gregg's NPI (1134787559) is active in the NPPES registry as of the last update on 2019-06-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.