2026 NPPES data Optometrist NPI 1639331614 O.D.
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Kieutien Tonnu, O.D.

Optometrist in Pomona, California. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers — including 60,463 in Optometrist, 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
165
Medicare Part D claims · 53 beneficiaries · Optometrist avg: 257
Generic prescribing
9%
generic claims · 91% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Kieutien Tonnu, O.D. filed 165 Medicare Part D claims in 2023 as a Optometrist in Pomona, California, prescribing 9% generic.

165
Part D claims, 2023
9%
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.

Kieutien Tonnu, O.D.'s Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

165 35th percentile higher than 35% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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

What does the federal data show about Kieutien Tonnu, O.D.?

Quality data not reported

NPI registry status

Active

Issued 06/30/2008

NPI 1639331614

Primary specialty

Optometrist

High-volume

60,463 US NPIs in this specialty

Medicare Part D claims

165 36% vs specialty avg

2023 prescription claims

Specialty avg: 257

Specialty distribution in California

How Optometrist compares to other specialties among California providers

California providers

Largest specialties in California (% of in-state providers)

Behavior Technician — 17.3%Behavior Technician17.3%Marriage & Family Therapist — 5.5%Marriage & Family Therapist5.5%Student in an Organized Health Care Education/Training Program — 5%Student in an Organized Health Care Education/Training Program5%Mental Health Counselor — 3.9%Mental Health Counselor3.9%Pharmacist — 3.5%Pharmacist3.5%Clinical Social Worker — 3.1%Clinical Social Worker3.1%Optometrist — 0.9%Optometrist0.9%
Largest specialties in California (% of in-state providers)

Specialty board-certification context

Estimated specialty board-certified rate — Optometrist (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Optometrist ABMS/AOA estimate

Est. board-certified rate (Optometrist) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Optometrist) — ABMS / AOA estimate

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).

Kieutien Tonnu, O.D. appears in the CMS NPPES registry as a Optometrist provider holding O.D. credentials at 1101 E HOLT AVE, Pomona, CA, 91767, with a listed phone of (909) 620-4546. NPI 1639331614 was issued on 06/30/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Tonnu most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 165 prescription claims written by this provider, covering 53 Medicare beneficiaries and totaling roughly $184K in drug spend, split 91% brand-name and 9% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Optometrist is a high-volume specialty nationwide, with 60,463 enrolled providers across 56 states and an average of 257 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

1101 E HOLT AVE
Pomona, CA 91767

Provider Details

NPI 1639331614
Specialty Optometrist
Credentials O.D.
Gender Female
NPI Issued 06/30/2008

License & disciplinary context — California MBC 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 ~150K California medical licensees in 2023 — they are NOT specific to Kieutien Tonnu, O.D.. To verify Kieutien Tonnu, O.D.'s current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC 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 California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Brand-heavy

Kieutien Tonnu, O.D. — brand share 91.0%
Optometrist average

91% brand-name claims vs 9% generic, on 165 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.

165
Total Claims
$184K
Total Drug Cost
53
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
325
Total Day Supply
9,735
Brand vs Generic
91% brand / 9% generic
Brand Drug Cost
$183K
Generic Drug Cost
$1K

Patient Demographics

Average Patient Age
75.1 years
Avg HCC Risk Score
0.87
Gender Split
53% female / 47% male

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Kieutien Tonnu, O.D. prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Xiidra
Lifitegrast
77
Restasis
Cyclosporine
42
Cyclosporine
31

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Optometrist Overview

How Kieutien Tonnu, O.D. fits within the Optometrist landscape nationally.

60,463
Optometrist Providers in US
56
States with Optometrist
257
Avg Claims per Provider

Kieutien Tonnu, O.D.'s 165 claims are below the specialty average of 257.

Nearby Optometrist Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Tonnu.

Compare Optometrist 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 California medical board — federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Optometrist 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.

Frequently Asked Questions

What is Kieutien Tonnu, O.D.'s specialty?
Kieutien Tonnu, O.D. specializes in Optometrist and practices in Pomona, California. Credentials: O.D..
How much does Kieutien Tonnu, O.D. prescribe under Medicare Part D?
In 2023, Kieutien Tonnu, O.D. wrote 165 Medicare Part D claims totaling $184K in drug costs for 53 beneficiaries.
Where is Kieutien Tonnu, O.D. located?
Kieutien Tonnu, O.D. is located at 1101 E HOLT AVE, Pomona, CA, 91767. Phone: (909) 620-4546.
What is Kieutien Tonnu, O.D.'s NPI number?
Kieutien Tonnu, O.D.'s National Provider Identifier (NPI) is 1639331614, issued on 06/30/2008.
Does Kieutien Tonnu, O.D. prescribe more brand-name or generic drugs?
Kieutien Tonnu, O.D.'s prescribing is 91% brand-name and 9% generic drugs by claim count, with $183K in brand drug costs.
How many Optometrist providers are there in the US?
There are 60,463 Optometrist providers across 56 states in the US. The average Optometrist provider writes 257 Medicare Part D claims per year.
What drugs does Kieutien Tonnu, O.D. prescribe most often?
Based on 2023 Medicare Part D data, Kieutien Tonnu, O.D.'s most frequently prescribed drugs include Xiidra, Restasis, Cyclosporine. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Kieutien Tonnu, O.D. accept Medicare?
Kieutien Tonnu, O.D. appears in CMS Medicare data with 165 Part D claims and 53 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Kieutien Tonnu, O.D.'s credentials?
Kieutien Tonnu, O.D.'s NPI is 1639331614 with credentials O.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

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.