Dr. William Parker Marks , MD
Ophthalmology • Canton, GA
125 Oakside Ct, Suite 102
Canton, GA 301142498
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
-
NPI assigned on September 23, 2005; this date does not establish years in practice.
-
Published CMS data list 847 Original Medicare Part B services in 2021.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2021. Published rows only; this is not a quality measure.
-
Published Part B service records, 2021:
- 92020 — Exam of the internal drainage system of eye: 222 service units.
- 99214 — Established patient outpatient office visit: 184 service units.
- 92014 — Established patient complete exam of visual system: 160 service units.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2021. Units differ by code; these are not visits or a measure of quality.
CPT® only copyright 2020 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2021). CPT notice
See all 9 records in the table · Guide: How to read Medicare Part B data
-
Published CMS data list 194 Medicare Part D prescriptions, including refills, in 2022.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2022. Published rows only; this is not a quality measure.
-
Published Part D records, 2022:
- Latanoprost — 84 prescription fills, including refills.
- Timolol Maleate — 63 prescription fills, including refills.
- Dorzolamide-Timolol (Dorzolamide Hcl/Timolol Maleat) — 34 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2022. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 4 records in the table · Guide: How to read Medicare Part D prescriber data
-
Medicare Part B services went from 3,177 in 2017 to 847 in 2021.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2017–2021.
Practice Location & Contact Primary Location
125 Oakside Ct
Suite 102
Canton, GA 301142498
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
What Public CMS Data Show
Ophthalmology: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare-allowed amount
About $68,019 in 2021
The total amount Medicare approved for these services in 2021. 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, 2021.
Paid by Medicare
About $40,709 in 2021
The part of the Medicare-allowed amount that Medicare itself paid in 2021, 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, 2021.
30-day fills
406 standardized 30-day fills in 2022
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
$5,257 in 2022
The total cost of these prescriptions in 2022, 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, 2022.
Open Payments general payments, program year 2025
All general payments: $459.90 across 3 records.
By nature of payment
- Food and Beverage: $459.90 across 3 records.
Reporting-company totals
- Glaukos Corporation: $186.57 across 1 record.
- Genentech, Inc.: $150.00 across 1 record.
- Johnson & Johnson Surgical Vision, Inc.: $123.33 across 1 record.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
NPI first issued
2005
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.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
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. Marks 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. Marks 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 Canton and Georgia
Billing and prescribing volume is not a quality rating.
Medicare Part B
Comparisons use 2024 data. The latest CMS data for Dr. Marks are from 2021.
Medicare Part D
Comparisons use 2024 data. The latest CMS data for Dr. Marks are from 2022.
5 active clinicians are listed under Ophthalmology with a practice address in Canton, GA (538 in Georgia).
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.
-
Medicare Part B services
Medicare Part B services decreased 73% from 3,177 in 2017 to 847 in 2021.
- 2017: 3,177
- 2018: 7,144
- 2019: 5,668
- 2020: 2,114
- 2021: 847
-
Medicare-allowed amount
Medicare-allowed amount decreased 73% from $248,983 in 2017 to $68,019 in 2021.
- 2017: $248,983
- 2018: $252,224
- 2019: $239,598
- 2020: $157,448
- 2021: $68,019
-
Paid by Medicare
Paid by Medicare decreased 76% from $172,129 in 2017 to $40,709 in 2021.
- 2017: $172,129
- 2018: $172,951
- 2019: $164,672
- 2020: $103,626
- 2021: $40,709
-
Medicare Part D prescriptions
Medicare Part D prescriptions decreased 93% from 2,890 in 2018 to 194 in 2022.
- 2018: 2,890
- 2019: 2,744
- 2020: 2,319
- 2021: 1,542
- 2022: 194
-
30-day fills
30-day fills decreased 90% from 4,133 in 2018 to 406 in 2022.
- 2018: 4,133
- 2019: 4,218
- 2020: 3,813
- 2021: 2,802
- 2022: 406
-
Part D drug cost
Part D drug cost decreased 97% from $190,716 in 2018 to $5,257 in 2022.
- 2018: $190,716
- 2019: $207,535
- 2020: $190,132
- 2021: $130,284
- 2022: $5,257
-
Industry payments (Open Payments)
Industry payments (Open Payments) went from $261.62 in 2021 to $459.90 in 2025.
- 2021: $261.62
- 2022: $252.79
- 2023: $806.43
- 2024: $295.45
- 2025: $459.90
Sources: CMS Medicare Physician & Other Practitioners (2021), CMS Medicare Part D Prescribers (2022), CMS Open Payments (2025), 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 2025 (payments made January 1 – December 31, 2025): fewer than 11 records totaling $459.90.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Glaukos Corporation |
Food and Beverage
Cash or cash equivalent
|
— | General | $186.57 |
| Genentech, Inc. |
Food and Beverage
In-kind items and services
|
Susvimo | General | $150.00 |
| Johnson & Johnson Surgical Vision, Inc. |
Food and Beverage
In-kind items and services
|
Tecnis IOL | General | $123.33 |
Source: CMS Open Payments, program year 2025, 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 2016–2020 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, 2017–2021; 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 |
|---|---|---|---|---|
|
92020
Exam of the internal drainage system of eye
|
222 | 217 | $85.00 | $28.03 |
|
99214
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more
|
184 | 164 | $175.00 | $129.98 |
|
92014
Established patient complete exam of visual system
|
160 | 160 | $225.00 | $127.33 |
|
92083
Exam of visual field with extended testing
|
74 | 73 | $185.00 | $64.00 |
|
92133
Imaging of optic nerve
|
65 | 65 | $175.00 | $37.57 |
|
99212
Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more
|
54 | 50 | $100.00 | $56.65 |
|
99213
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more
|
40 | 39 | $125.00 | $92.04 |
|
92250
Photography of the retina
|
33 | 33 | $175.00 | $39.60 |
|
92004
New patient complete exam of visual system
|
15 | 15 | $250.00 | $152.14 |
Source: CMS Part B by Provider and Service, 2021; 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 2022.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Latanoprost | Latanoprost | 84 | 4,604 | $1,784.40 | 43 |
| Timolol Maleate | Timolol Maleate | 63 | 4,053 | $2,024.24 | 38 |
| Dorzolamide-Timolol | Dorzolamide Hcl/Timolol Maleat | 34 | 2,208 | $988.99 | 18 |
| Dorzolamide Hcl | Dorzolamide Hcl | 13 | 1,090 | $459.23 | — |
Source: CMS Part D by Provider and Drug, 2022; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
NUCC 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
I20101108000900
GA
9739256397
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Career & Practice History
NPI enumerated September 23, 2005.
No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from January 2017 to August 2026.
NPI Administrative Meta
Other Ophthalmology Specialists in Canton
Healthcare providers in CantonMailing Address
125 Oakside Ct, Suite 102
Canton, GA 301142498
Phone: 6788800662