Theresa Boi Ngoc Nguyen, OD
NPI 1437896180ActiveIndividual· Optometrist· Merced, CA
Optometrist (OD) with Johann J Schlager Od Inc, practicing in Merced, California. Medicare paid $10,297 for services to 102 patients in 2024. Alcon Vision LLC reported $171.36 in payments in 2025, mostly food and beverage.
Overview
| NPI | 1437896180 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | OD |
| Sole proprietor | No |
| NPI issued | May 15, 2022 |
| Last updated in NPPES | May 15, 2022 |
| Certified by provider | May 15, 2022 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Optometrist Primary | 152W00000X | 35123 | CA |
| Optometrist, Corneal and Contact Management | 152WC0802X | 35123 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Optometry (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 102 |
|---|---|
| Services billed | 153 across 12 procedure codes |
| Paid by Medicare | $10,297 |
Education and affiliations
| Graduation year | 2021 |
|---|---|
| Medicare specialty | Optometry |
Medical group
- Johann J Schlager Od IncMerced, CA · 3 clinicians
Industry payments (Open Payments)
- 2025$171.36 · 7 payments from 1 company
- 2024$218.62 · 9 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Alcon Vision LLC | $171.36 | 7 |
What the 2025 payments were for
- Food and Beverage$171.36 · 7 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 31 optometrists in Merced · All optometrists in California