Dr. Robert Chang, MD
What this data tells you about Dr. Chang
Dr. Robert Chang is an ophthalmology specialist in Stanford, CA, with 19 years of NPI registration. Based on federal Medicare data, Dr. Chang performed 2,356 Medicare services across 2,034 unique beneficiaries.
Between the years covered by Open Payments, Dr. Chang received a total of $90,099 from 28 pharmaceutical and/or device companies across 266 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common in ophthalmology. The majority of payments are for consulting, which typically reflects recognized clinical expertise sought by manufacturers. Patients may wish to discuss these relationships with their provider.
The Data Coverage level for Dr. Chang is Very High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
Medicare Practice Summary
Medicare Utilization ↗Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| Office visit, established patient (30-39 min) A follow-up office visit for an existing patient lasting between 30 and 39 minutes. The visit involves medical evaluation and management of the patient's condition. |
377 | $80 | $118 |
| Office visit, established patient (20-29 min) An office visit for an existing patient lasting between 20 and 29 minutes. The visit involves medical evaluation and management of the patient's condition. |
366 | $54 | $80 |
| Visual field test, extended A test that maps your complete field of vision to detect blind spots or peripheral vision loss. Extended testing provides a more detailed assessment than a standard visual field exam. |
340 | $24 | $183 |
| Optic nerve imaging (OCT scan) Imaging of the optic nerve. |
327 | $19 | $73 |
| CT scan of cornea A computed tomography scan used to create detailed images of the cornea, the clear front part of the eye. |
117 | $18 | $81 |
| Corneal topography and eye depth measurement This procedure measures the curvature and depth of the cornea, the clear front surface of the eye. |
102 | $28 | $141 |
| Office visit, established patient, complex (40-54 min) An office or outpatient visit for an existing patient lasting between 40 and 54 minutes. This level of service is determined by the total time spent on the date of the encounter. |
95 | $119 | $180 |
| Comprehensive eye exam, established patient A comprehensive examination of the visual system performed for a patient who has previously been seen by the provider. |
80 | $69 | $235 |
| Retinal imaging (OCT scan) This procedure involves imaging the retina to visualize its structure. It is used to examine the back of the eye. |
77 | $22 | $78 |
| Cataract surgery with lens implant Surgical removal of the clouded natural lens of the eye and replacement with an artificial prosthetic lens to restore vision. |
71 | $511 | $5,166 |
| Eye drainage system examination An examination of the internal drainage system of the eye to assess how fluid flows and drains from the eye. |
67 | $18 | $96 |
| Ultrasound scan of cornea to determine thickness An ultrasound procedure used to measure the thickness of the cornea. |
54 | $7 | $50 |
| New patient office visit (45-59 min) An initial office visit for a new patient lasting between 45 and 59 minutes. This code covers the total time spent by the physician or qualified healthcare professional on the date of the encounter. |
50 | $110 | $182 |
| Laser removal of recurring cataract A laser procedure to remove a recurring cataract within the lens capsule. |
45 | $312 | $1,240 |
| Complex cataract removal with lens implant A surgical procedure to remove a cataract from the eye and insert an artificial lens to restore vision. |
40 | $727 | $6,375 |
| Cataract removal with artificial lens and drainage device insertion Surgical removal of the eye's natural lens followed by the insertion of an artificial lens and a drainage device into the front chamber of the eye. |
34 | $671 | $8,279 |
| Eye exam, established patient, focused A limited examination of the visual system for an existing patient. The provider focuses on a specific eye-related concern or symptom. |
23 | $45 | $157 |
| Comprehensive eye exam, new patient A comprehensive examination of the visual system performed for a new patient. |
22 | $79 | $324 |
| Laser repair to improve eye fluid flow A laser procedure used to enhance the drainage of fluid within the eye. |
21 | $188 | $1,000 |
| Eye shunt creation with tissue graft A surgical procedure to create a drainage pathway for eye fluid using a tissue graft to improve fluid flow. |
21 | $1,104 | $7,500 |
| Retinal photography (fundus photo) This procedure involves taking photographs of the retina, the light-sensitive tissue at the back of the eye. It is used to document the condition of the eye's interior structures. |
15 | $19 | $291 |
| Slit lamp examination of the eye This procedure uses a specialized microscope to examine the front portion of the eye. |
12 | $20 | $133 |
Industry Payment Transparency
Open Payments through 2024 ↗Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
Payments by company (2024)
All-time payments by company (2018-2024) ›
Associated products mentioned in payments ›
The majority of payments (80%) are consulting fees, which typically reflect recognized clinical expertise sought by manufacturers. Total industry engagement is in the top 5% for ophthalmology in CA.
Geographic Context
0.0 mi
Data Sources
| Provider Registry | ✓ NPPES | Weekly updates |
| Medicare Enrollment | ✓ PECOS | Monthly updates |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not public | N/A |
This provider has data in 4 of 4 available federal datasets, with a Data Coverage level of Very High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Chang is a clinical cardiology specialist, with moderate Medicare volume, with consulting-driven industry engagement in the top 5% of CA peers, with 19 years of NPI registration.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
Is Dr. Chang experienced with office visit, established patient (30-39 min)?
Does Dr. Chang receive payments from pharmaceutical companies?
How do Dr. Chang's costs compare to other ophthalmologists in Stanford?
What does Data Coverage mean?
Is this data up to date?
Explore related providers
All data on this page is sourced verbatim from public federal records published by the U.S. Centers for Medicare & Medicaid Services (CMS): NPPES ↗, Open Payments ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
Provider corrections: Provider portal · Privacy questions: Privacy Policy · Terms: Terms of Use · Methodology: Methodology