NATHAN QUIN LEUNG OD
NPI 1801784491
Optometrist in San Dimas, CA

NPI Status: Active since June 24, 2025

Contact Information

520 N LONE HILL AVE
SAN DIMAS, CA
ZIP 91773
Phone: (909) 394-4545

NPI Profile Information
Primary Taxonomy
NPI Validation
Other Providers Same Location
Frequently Asked Questions

Individual
Male
Optometrist

About NATHAN LEUNG

This page provides the complete NPI Profile along with additional information for Nathan Leung, a provider established in San Dimas, California with a medical specialization in Optometrist. The healthcare provider is registered in the NPI registry with number 1801784491 assigned on June 2025. The practitioner's primary taxonomy code is 152W00000X with license number 35958 (CA). The provider is registered as an individual and his NPI record was last updated one year ago.

NPI: 1801784491
Provider Name: NATHAN QUIN LEUNG OD
Gender: Male
Entity Type: Individual
Location Address: 520 N LONE HILL AVE SAN DIMAS, CA 91773
Location Phone: (909) 394-4545
Mailing Address: 1350 AVONREA RD SAN MARINO, CA 91108
Mailing Phone: (562) 291-9749
Is Sole Proprietor?: No
Enumeration Date: 06-24-2025
Last Update Date: 06-24-2025
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Specialty - Primary Taxonomy

The NPI enumerator requires providers to submit at least one taxonomy code. A taxonomy code is a unique 10-character code that describes the healthcare provider type, classification, and the area of specialization. There could be only one primary taxonomy code per NPI record. For individual NPIs the license data is associated to the taxonomy code.

Classification: Optometrist
Taxonomy Code: 152W00000X
Type: Eye and Vision Services Providers
License No.: 35958
License State: CA
Taxonomy Description: Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. An optometrist has completed pre-professional undergraduate education in a college or university and four years of professional education at a college of optometry, leading to the doctor of optometry (O.D.) degree. Some optometrists complete an optional residency in a specific area of practice. Optometrists are eye health care professionals state-licensed to diagnose and treat diseases and disorders of the eye and visual system.

NPI NPI Number Validation

How NPI Validation Works

The NPI validation process uses the ISO-standard Luhn algorithm, a mathematical "handshake", to ensure that a provider's 10-digit ID is authentic and free of common typing errors.

To verify the NPI 1801784491, we treat the final digit (1) as the Check Digit—the target answer we need to reach. The process begins by taking the first nine digits and adding a constant value of 24, which accounts for the "80840" prefix required for all U.S. health identifiers. We then double every other digit starting from the right and sum the individual digits of those results together. For this specific NPI, that total comes to 69. The final step is to find the difference between that total and the next multiple of ten (70 - 69 = 1).

Digit-by-digit view

Use the first nine digits for the calculation. Starting from the right, double every other digit. The last digit is the check digit and is not part of the calculation.

Pos 1

Doubled → 2

Pos 2

Unchanged

Pos 3

Doubled → 0

Pos 4

Unchanged

Pos 5

Doubled → 14 → 1 + 4

Pos 6

Unchanged

Pos 7

Doubled → 8

Pos 8

Unchanged

Pos 9

Doubled → 18 → 1 + 8

Check

Target digit

Regular digit Doubled digit Check digit

Step 1: Double every other digit from the right

Starting with the rightmost digit of the first nine digits, double every other value. If doubling creates a two-digit number, add those digits together.

1 → 2 0 → 0 7 → 14 → 5 4 → 8 9 → 18 → 9

Step 2: Add all digits plus the NPI constant

Add the transformed values, the unchanged digits, and the constant 24.

2 + 8 + 0 + 1 + 1 + 4 + 8 + 8 + 4 + 1 + 8 + 24 = 69

Step 3: Find the amount needed to reach the next multiple of 10

The next multiple of ten after 69 is 70. The difference is the calculated check digit.

70 - 69 = 1

This NPI is valid

The calculated check digit is 1, which matches the last digit of 1801784491.