Gregory Spencer, M.D.
NPI 1821127770 · Ophthalmology Physician · Oxnard, CA
Enrolled with Medicare as Practitioner - Ophthalmology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gregory Spencer, M.D. is a Ophthalmology Physician provider in Oxnard, CA (NPI 1821127770).
Provider details
- NPI number
- 1821127770
- Entity type
- Individual
- Primary specialty
- Ophthalmology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- G072734 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 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
2,138 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 Problem Focused Exam of Visual System92012 | 858 | $94 |
| Measurement of Corneal Curvature and Depth of Eye92136 | 291 | $41 |
| Removal of Cataract With Insertion of Prosthetic Lens66984 | 253 | $505 |
| New Patient Complete Exam of Visual System92004 | 176 | $156 |
| Established Patient Complete Exam of Visual System92014 | 127 | $132 |
| Removal of Recurring Cataract in Lens Capsule Using a Laser66821 | 124 | $428 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 16 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Latanoprost | 119 | 32 |
| Besifloxacin Hclbrand: Besivance | 98 | 65 |
| Timolol Maleate | 81 | 27 |
| Loteprednol Etabonatebrand: Lotemax Sm | 54 | 38 |
| Tobramycin/Dexamethasonebrand: Tobramycin-Dexamethasone | 44 | 31 |
| Prednisolone Acetate | 44 | 22 |
| Bromfenac Sodiumbrand: Prolensa | 39 | 31 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$39 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
- 2007-03-05
- Last updated
- 2007-09-26
Frequently asked questions
- What is Gregory Spencer's NPI number?
- Gregory Spencer's National Provider Identifier (NPI) is 1821127770, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gregory Spencer's specialty?
- Gregory Spencer is listed in the NPPES registry with a primary specialty of Ophthalmology Physician (Allopathic & Osteopathic Physicians).
- Where is Gregory Spencer located?
- Gregory Spencer's practice location on file with NPPES is 1200 W Gonzales Rd Ste 200, Oxnard, CA 93036-3074.
- What is Gregory Spencer's phone number?
- The practice phone number listed in the NPPES registry for Gregory Spencer is (805) 983-0923.
- Does Gregory Spencer accept Medicare?
- Gregory Spencer is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gregory Spencer's NPI active?
- Yes — Gregory Spencer's NPI (1821127770) is active in the NPPES registry as of the last update on 2007-09-26.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.