Dr. Nathan C Hamaker , MD
Ophthalmology • Lancaster, CA
44439 17th St W # 210
Lancaster, CA 935342831
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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NPI assigned on June 23, 2006; this date does not establish years in practice.
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Published CMS data list 1,630 Original Medicare Part B services in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Published rows only; this is not a quality measure.
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Published Part B service records, 2024:
- 92014 — Established patient complete exam of visual system: 555 service units.
- 92012 — Established patient problem focused exam of visual system: 172 service units.
- 92133 — Imaging of optic nerve: 150 service units.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Units differ by code; these are not visits or a measure of quality.
CPT® only copyright 2023 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2024). CPT notice
See all 15 records in the table · Guide: How to read Medicare Part B data
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Published CMS data list 2,650 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Latanoprost — 1,331 prescription fills, including refills.
- Dorzolamide-Timolol (Dorzolamide Hcl/Timolol Maleat) — 306 prescription fills, including refills.
- Neomycin-Polymyxin-Dexameth (Neomycin/Polymyxin B/Dexametha) — 228 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 15 records in the table · Guide: How to read Medicare Part D prescriber data
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Close to the middle for Medicare Part B services among clinicians listed under Ophthalmology in California (2024, 1,572 clinicians with data). Median for this group: 1,776. Middle half: 600 to 3,873.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 3,046 in 2020 to 1,630 in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2020–2024.
Practice Location & Contact Primary Location
44439 17th St W # 210
Lancaster, CA 935342831
CMS Doctors and Clinicians lists 1 group name: Seibert Mobile Optometry Llc. See the list
Source: CMS Doctors and Clinicians National Downloadable File, release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File
University Of Texas Medical School At Houston
2003
What Public CMS Data Show
Ophthalmology: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
794 people with Original Medicare in 2024
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners – by Provider, 2024.
Medicare-allowed amount
About $186,321 in 2024
The total amount Medicare approved for these services in 2024. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
Paid by Medicare
About $122,806 in 2024
The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
30-day fills
4,476 standardized 30-day fills in 2024
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$112,054 in 2024
The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024.
Industry payments (Open Payments)
Fewer than 11 payment records totaling $19.99 in 2024
Drug and medical device companies must report certain payments to doctors and some other clinicians to CMS, such as meals, travel, speaking fees or research funding.
It shows reported financial ties between this clinician and companies. You can ask your clinician about them.
These records are submitted by drug and medical device companies, and a reported payment does not necessarily mean the financial relationship is improper.
General: payments not tied to research, such as meals, travel, consulting or speaking fees.
A reported payment does not necessarily mean the financial relationship is improper. Research payments can go to a hospital or university for a study the clinician leads, not to the clinician personally. Clinicians can dispute records with the company that reported them.
Source: CMS Open Payments, program year 2024.
Years since graduation
23 years (graduated 2003)
CMS Doctors and Clinicians data list 2003 as the year this clinician finished professional school.
It tells you roughly how long ago the clinician finished school.
What this does not show: Years since graduation
It is not the number of years in practice, and more years does not mean better care.
Source: CMS Doctors and Clinicians National Downloadable File.
NPI first issued
2006
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Accepts Medicare assignment
CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.
With Original Medicare, you usually pay only your deductible and coinsurance, and the office sends the claim to Medicare for you.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, “Does your provider accept Medicare as full payment?”
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Enrolled in Medicare (PECOS)
Dr. Hamaker has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Can order Medicare-covered services
CMS lists Dr. Hamaker as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Lancaster and California
Billing and prescribing volume is not a quality rating.
Medicare Part B services
Close to the middle for clinicians listed under Ophthalmology in California (2024, 1,572 clinicians with data). Median for this group: 1,776. Middle half: 600 to 3,873.
Too few clinicians listed under Ophthalmology in Lancaster have Medicare Part B data for 2024 to compare.
Medicare-allowed amount
Close to the middle for clinicians listed under Ophthalmology in California (2024, 1,572 clinicians with data). Median for this group: $209,264. Middle half: $67,828 to $437,264.
Too few clinicians listed under Ophthalmology in Lancaster have Medicare Part B data for 2024 to compare.
Paid by Medicare
Close to the middle for clinicians listed under Ophthalmology in California (2024, 1,572 clinicians with data). Median for this group: $152,036. Middle half: $48,721 to $320,363.
Too few clinicians listed under Ophthalmology in Lancaster have Medicare Part B data for 2024 to compare.
Medicare Part D prescriptions
More Part D prescriptions than 80% of clinicians listed under Ophthalmology in California (2024, 1,966 clinicians with data). Median for this group: 1,025. Middle half: 297 to 2,233.
Too few clinicians listed under Ophthalmology in Lancaster have Medicare Part D data for 2024 to compare.
Part D drug cost
Close to the middle for clinicians listed under Ophthalmology in California (2024, 1,966 clinicians with data). Median for this group: $79,352. Middle half: $13,075 to $224,408.
Too few clinicians listed under Ophthalmology in Lancaster have Medicare Part D data for 2024 to compare.
7 active clinicians are listed under Ophthalmology with a practice address in Lancaster, CA (2,902 in California).
Addresses are self-reported to NPPES and may be out of date.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part B services
Medicare Part B services decreased 46% from 3,046 in 2020 to 1,630 in 2024.
- 2020: 3,046
- 2021: 3,235
- 2022: 3,327
- 2023: 2,827
- 2024: 1,630
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Medicare-allowed amount
Medicare-allowed amount decreased 50% from $372,237 in 2020 to $186,321 in 2024.
- 2020: $372,237
- 2021: $370,530
- 2022: $380,348
- 2023: $319,768
- 2024: $186,321
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Paid by Medicare
Paid by Medicare decreased 54% from $264,838 in 2020 to $122,806 in 2024.
- 2020: $264,838
- 2021: $266,216
- 2022: $265,207
- 2023: $224,417
- 2024: $122,806
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Medicare Part D prescriptions
Medicare Part D prescriptions stayed about the same: 2,741 in 2020 and 2,650 in 2024.
- 2020: 2,741
- 2021: 2,673
- 2022: 3,043
- 2023: 3,262
- 2024: 2,650
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30-day fills
30-day fills stayed about the same: 4,733 in 2020 and 4,476 in 2024.
- 2020: 4,733
- 2021: 4,714
- 2022: 5,325
- 2023: 5,485
- 2024: 4,476
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Part D drug cost
Part D drug cost decreased 61% from $283,843 in 2020 to $112,054 in 2024.
- 2020: $283,843
- 2021: $236,924
- 2022: $216,475
- 2023: $219,200
- 2024: $112,054
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $80.89 in 2020 to $19.99 in 2024.
- 2020: $80.89
- 2021: $15.48
- 2022: $44.86
- 2023: $17.88
- 2024: $19.99
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2024), CMS Open Payments (2024), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo · Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2024 (payments made January 1 – December 31, 2024): fewer than 11 records totaling $19.99.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Bausch & Lomb Americas Inc. |
Food and Beverage
In-kind items and services
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XIIDRA | General | $19.99 |
Source: CMS Open Payments, program year 2024, released June 30, 2026.
Performed Procedures & Service Volume
CPT® is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016–2023 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners – by Provider and Service data, 2017–2024; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
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92014
Established patient complete exam of visual system
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555 | 535 | $198.07 | $123.58 |
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92012
Established patient problem focused exam of visual system
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172 | 144 | $150.91 | $87.23 |
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92133
Imaging of optic nerve
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150 | 150 | $63.73 | $35.64 |
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92004
New patient complete exam of visual system
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130 | 130 | $172.35 | $147.70 |
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92083
Exam of visual field with extended testing
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99 | 98 | $107.27 | $61.47 |
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76514
Ultrasound scan of cornea to determine thickness
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91 | 91 | $21.50 | $10.49 |
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92020
Exam of the internal drainage system of eye
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90 | 90 | $46.60 | $26.95 |
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92136
Measurement of corneal curvature and depth of eye
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86 | 46 | $120.00 | $38.42 |
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66984
Removal of cataract with insertion of prosthetic lens
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81 | 46 | $1355.00 | $532.93 |
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92250
Photography of the retina
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52 | 51 | $85.50 | $36.37 |
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92134
Imaging of retina
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39 | 39 | $69.67 | $39.69 |
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66821
Removal of recurring cataract in lens capsule using a laser
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26 | 17 | $572.35 | $306.28 |
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99309
Subsequent nursing facility care with moderate level of medical decision making, per day, if using time, at least 30 minutes
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24 | 24 | $108.42 | $108.29 |
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66821
Removal of recurring cataract in lens capsule using a laser
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22 | 14 | $619.18 | $330.56 |
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99308
Subsequent nursing facility care with straightforward level of medical decision making, per day, if using time, 20 minutes or more
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13 | 13 | $74.94 | $74.84 |
Source: CMS Part B by Provider and Service, 2024; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Latanoprost | Latanoprost | 1,331 | 67,186 | $13,463.93 | 293 |
| Dorzolamide-Timolol | Dorzolamide Hcl/Timolol Maleat | 306 | 16,846 | $4,165.43 | 74 |
| Neomycin-Polymyxin-Dexameth | Neomycin/Polymyxin B/Dexametha | 228 | 5,291 | $4,832.51 | 136 |
| Timolol Maleate | Timolol Maleate | 213 | 12,664 | $1,573.35 | 59 |
| Travoprost | Travoprost | 122 | 4,397 | $11,602.61 | 24 |
| Brimonidine Tartrate | Brimonidine Tartrate | 102 | 3,803 | $2,415.03 | 23 |
| Prednisolone Acetate | Prednisolone Acetate | 71 | 2,572 | $2,901.42 | 41 |
| Lumigan | Bimatoprost | 63 | 3,589 | $34,435.41 | 20 |
| Brimonidine Tartrate-Timolol | Brimonidine Tartrate/Timolol | 52 | 2,170 | $8,674.05 | 13 |
| Dorzolamide Hcl | Dorzolamide Hcl | 47 | 3,092 | $1,023.68 | 13 |
| Tobramycin-Dexamethasone | Tobramycin/Dexamethasone | 33 | 705 | $2,768.51 | 22 |
| Ketorolac Tromethamine | Ketorolac Tromethamine | 25 | 470 | $473.00 | 23 |
| Valacyclovir | Valacyclovir Hcl | 23 | 953 | $704.07 | — |
| Combigan | Brimonidine Tartrate/Timolol | 22 | 1,245 | $10,226.97 | — |
| Cyclosporine | Cyclosporine | 12 | 1,080 | $12,793.86 | — |
Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
Self-certified to NPPES: 2026-06-29NUCC Taxonomy Code: 207W00000X
An ophthalmologist has the knowledge and professional skills needed to provide comprehensive eye and vision care. Ophthalmologists are medically trained to diagnose, monitor and medically or surgically treat all ocular and visual disorders. This includes problems affecting the eye and its component structures, the eyelids, the orbit and the visual pathways. In so doing, an ophthalmologist prescribes vision services, including glasses and contact lenses.
Additional State Medicaid & Healthcare Payer Identifiers
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - OPHTHALMOLOGY
I20070801000603
MO
7517058894
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Medicare Group Practice Enrollments
Source: CMS Doctors and Clinicians National Downloadable File
Seibert Mobile Optometry Llc
12758 Honeygrove Ct, Saint Louis, MO 631464405
Phone: 24852821166
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at 44439 17TH ST W # 210, LANCASTER, CA 935342831 (Tel: 8168383464)
Registered at 44439 17TH ST W # 210, LANCASTER, CA 935342831 (Tel: 8168383464)
Ophthalmology (license number reported to NPPES: CA C205778)
NPI status registered as active in NPPES database
Registered at 1613 S 7 HWY, BLUE SPRINGS, MO 640143946 (Tel: 8164781230)
Registered at 4801 S CLIFF AVE, SUITE 100, INDEPENDENCE, MO 640557015 (Tel: 8164781230)
Recorded as NATHAN HAMAKER, MD
Ophthalmology (license number reported to NPPES: MO 2007010850)
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Ophthalmology Specialists in Lancaster
Healthcare providers in LancasterMailing Address
44439 17th St W # 210
Lancaster, CA 935342831
Phone: 8168383464