NPI registry status
Active
2026 NPPES data Ophthalmology Physician NPI 1851411847 M.D.
Verify on CMS → Gregory Doren, M.D.
Ophthalmology Physician in Chicago, Illinois.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 22,082 in Ophthalmology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
2K
Medicare Part D claims · 425 beneficiaries · Ophthalmology Physician avg: 1K
Generic prescribing
58%
generic claims · 42% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Gregory Doren, M.D. filed 2,116 Medicare Part D claims in 2023 as a Ophthalmology Physician in Chicago, Illinois, prescribing 58% generic.
- 2K
- Part D claims, 2023
- 58%
- generic prescribing
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Gregory Doren, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
2,116 Top 15% higher than 85% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
◑
Board-eligible specialty (heuristic, not verified)
Gregory Doren, M.D. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Gregory Doren, M.D.?
Quality data not reportedPrimary specialty
Ophthalmology Physician
Medicare Part D claims
2,116 49% vs specialty avg
Specialty distribution in Illinois
How Ophthalmology Physician compares to other specialties among Illinois providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Ophthalmology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Gregory Doren, M.D. appears in the CMS NPPES registry as a Ophthalmology Physician provider holding M.D. credentials at 3000 N HALSTED ST, Chicago, IL, 60657, with a listed phone of (773) 935-2800. NPI 1851411847 was issued on 03/31/2007.
Medicare Part D records for calendar year 2023 show 2,116 prescription claims written by this provider, covering 425 Medicare beneficiaries and totaling roughly $133K in drug spend, split 42% brand-name and 58% generic by claim count.
Ophthalmology Physician is a mid-sized specialty nationwide, with 22,082 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.
Practice Address
Provider Details
| NPI | 1851411847 |
|---|---|
| Specialty | Ophthalmology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 03/31/2007 |
License & disciplinary context - Illinois IDFPR 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~42K Illinois medical licensees in 2023 - they are NOT specific to Gregory Doren, M.D.. To verify Gregory Doren, M.D.'s current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases
IDFPR publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Above average
Gregory Doren, M.D. - brand share 42.0%
Ophthalmology Physician average
42% brand-name claims vs 58% generic, on 2,116 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
2,116
Total Claims
$133K
Total Drug Cost
425
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 3,715
- Total Day Supply
- 101,472
- Brand vs Generic
- 42% brand / 58% generic
- Brand Drug Cost
- $99K
- Generic Drug Cost
- $34K
- Antibiotic Claims
- 12
Patient Demographics
- Average Patient Age
- 74.9 years
- Avg HCC Risk Score
- 1.16
- Gender Split
- 64% female / 36% male
- Age Distribution
- <65: 22, 65-74: 201, 75-84: 142, 85+: 60
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Gregory Doren, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Latanoprost
Latanoprost
680 claims
- Prednisolone Acetate 235
Prednisolone Acetate
235 claims
- Dorzolamide Hcl 210
Dorzolamide Hcl
210 claims
- Erythromycin 165
Erythromycin
165 claims
- Timolol Maleate 162
Timolol Maleate
162 claims
- Ketorolac Trometha… 129
Ketorolac Tromethamine
129 claims
- Ciprofloxacin Hcl 110
Ciprofloxacin Hcl
110 claims
- Brimonidine Tartrate 92
Brimonidine Tartrate
92 claims
| Drug | Claims |
|---|---|
| Latanoprost | 680 |
| Prednisolone Acetate | 235 |
| Dorzolamide Hcl | 210 |
| Erythromycin Erythromycin Base | 165 |
| Timolol Maleate | 162 |
| Ketorolac Tromethamine | 129 |
| Ciprofloxacin Hcl | 110 |
| Brimonidine Tartrate | 92 |
| Tobramycin-Dexamethasone Tobramycin/Dexamethasone | 70 |
| Dorzolamide-Timolol Dorzolamide Hcl/Timolol Maleat | 51 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Ophthalmology Physician Overview
How Gregory Doren, M.D. fits within the Ophthalmology Physician landscape nationally.
22,082
Ophthalmology Physician Providers in US
56
States with Ophthalmology Physician
1,420
Avg Claims per Provider
Gregory Doren, M.D.'s 2,116 claims are above the specialty average of 1,420.
Nearby Ophthalmology Physician Providers in Illinois
Other clinicians with the same primary specialty enrolled in Illinois, drawn from the same CMS NPPES roster as Doren.
Dr. Walid Abdallah
MD
Rockford, IL
Dr. Ashley Abraham
M.D.
Springfield, IL
Dr. Evelyn Ackermann
MD
Elgin, IL
Dr. Kathleen Ackman Blake
MD
Hinsdale, IL
Dr. Kaela Acuff
MD
Chicago, IL
Compare Ophthalmology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Illinois medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Ophthalmology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Gregory Doren, M.D.'s specialty? ▼
Gregory Doren, M.D. specializes in Ophthalmology Physician and practices in Chicago, Illinois. Credentials: M.D..
How much does Gregory Doren, M.D. prescribe under Medicare Part D? ▼
In 2023, Gregory Doren, M.D. wrote 2,116 Medicare Part D claims totaling $133K in drug costs for 425 beneficiaries.
Where is Gregory Doren, M.D. located? ▼
Gregory Doren, M.D. is located at 3000 N HALSTED ST, Chicago, IL, 60657. Phone: (773) 935-2800.
What is Gregory Doren, M.D.'s NPI number? ▼
Gregory Doren, M.D.'s National Provider Identifier (NPI) is 1851411847, issued on 03/31/2007.
Does Gregory Doren, M.D. prescribe more brand-name or generic drugs? ▼
Gregory Doren, M.D.'s prescribing is 42% brand-name and 58% generic drugs by claim count, with $99K in brand drug costs.
How many Ophthalmology Physician providers are there in the US? ▼
There are 22,082 Ophthalmology Physician providers across 56 states in the US. The average Ophthalmology Physician provider writes 1,420 Medicare Part D claims per year.
What drugs does Gregory Doren, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Gregory Doren, M.D.'s most frequently prescribed drugs include Latanoprost, Prednisolone Acetate, Dorzolamide Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Gregory Doren, M.D. accept Medicare? ▼
Gregory Doren, M.D. appears in CMS Medicare data with 2,116 Part D claims and 425 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Gregory Doren, M.D.'s credentials? ▼
Gregory Doren, M.D.'s NPI is 1851411847 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.