John C. Kortenber, OD
- Medicare patients, 2024
- 313
- Part D claims, 2024
- 320
- Industry payments
- $32
- Affiliated sites
- 1
- Medical group
- 1
- Practice address
- 112 N Thorington St, Algona, IA 50511-2614
- Practice phone
- Call (515) 395-3937
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
John C Kortenber Optometry Pc
Physician office · Algona, Iowa
Find John Kortenber's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
John C. Kortenber is an optometrist in Algona, Iowa
John Kortenber practices at John C Kortenber Optometry Pc in Algona, Iowa.
John Kortenber's NPI, 1821049586, was assigned on May 15, 2006. John Kortenber graduated from University of Missouri St Louis - School of Optometry in 2001. John Kortenber holds Missouri license 2002014339.
- NPI
- 1821049586NPI Registry (opens in a new tab)
- Medicare PAC ID
- 9032154182
- NPI enumeration date
- May 15, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (515) 395-3937
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 51
- Medical school graduation
- 2001
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
John C. Kortenber practices at John C Kortenber Optometry Pc in Algona, Iowa
John Kortenber's primary practice is John C Kortenber Optometry Pc, at 112 N Thorington St, Algona, IA 50511-2614. The practice phone is (515) 395-3937.
- John C Kortenber Optometry Pc112 N Thorington St, Algona, IA 50511-2614Phone(515) 395-3937
Source: Dmand AI Affiliation Data
John C. Kortenber is affiliated with 1 site of care and 1 medical group
John Kortenber's primary practice is John C Kortenber Optometry Pc in Algona, Iowa. Dmand AI also links John Kortenber to 1 medical group, named with a free account.
Source: Dmand AI Affiliation Data
Dmand AI tracks the EHR system at John C. Kortenber's practice
Dmand AI tracks the electronic health record (EHR) system at each site where John Kortenber practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| John C Kortenber Optometry Pc | Available with a free account |
| +1 medical group | Available with a free account |
Source: Dmand AI Technology Install Data
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John C. Kortenber is one of 501 optometrists in Iowa
Optometrist is John Kortenber's primary specialty in the NPI Registry, under taxonomy code 152W00000X. John Kortenber is licensed in Missouri.
Specialties and state licenses
- Optometrist, MissouriPrimary
Optometrists near John Kortenber
Counts of optometrists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
John C. Kortenber treated 313 Medicare patients in 2024, average age 75
CMS counts 313 Medicare patients who saw John Kortenber in 2024. The largest group is 65 to 74, with 167 patients. 73% of them have high blood pressure, and 71% have high cholesterol. Their average risk score is 0.90, where 1.00 is the Medicare average.
Across all payers, Dmand AI patient panel data puts John Kortenber's median patient age at 62, with 53% women.
John Kortenber's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
John Kortenber's Medicare patients by sex, 2024
- Women19161%
- Men12239%
Chronic conditions among John Kortenber's Medicare patients, 2024
- High blood pressure73%
- High cholesterol71%
- Arthritis43%
- Diabetes28%
- Anxiety19%
- Ischemic heart disease19%
- Mood disorders19%
- Depression18%
Share of Medicare patients with each condition. A patient can have several.
John Kortenber's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 62
Patient panel by sex, all payers
- Women53%
- Men45%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
John C. Kortenber wrote 320 Medicare Part D claims in 2024
In 2024, John Kortenber wrote 320 Medicare Part D claims for 73 patients. 93% of them were for generic drugs.
John Kortenber's Part D claims by kind of drug, 2024
- Generic296 claims93%
- Brand-name24 claims8%
Source: Medicare Part D Prescribers - by Provider (CMS), 2024 data
John C. Kortenber ranks in the 64th percentile for cataract surgery in Medicare
John Kortenber accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS counts 53 procedures of cataract surgery by John Kortenber, more than 64% of the clinicians it reports for that procedure.
- Accepts Medicare assignment
- Yes
Where John Kortenber ranks in Medicare procedure volume
- Cataract surgery
- 64th percentile53 procedures
CMS ranks each clinician against every clinician it reports for the same procedure category.
Sources: Doctors and Clinicians National Downloadable File (CMS); and Doctors and Clinicians Utilization Data (CMS)
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John C. Kortenber received $32 in industry payments in 2025
CMS Open Payments shows 1 general payment to John Kortenber from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. LKC Technologies, Inc. paid the most, $32.
Companies that paid John Kortenber the most, 2025 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
John C. Kortenber graduated from University of Missouri St Louis - School of Optometry
John Kortenber graduated from University of Missouri St Louis - School of Optometry in 2001.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for John C. Kortenber's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation Data |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Doctors and Clinicians Utilization Data (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about John C. Kortenber
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is John C. Kortenber's NPI number?
John C. Kortenber's NPI number is 1821049586. It was assigned on May 15, 2006, and it is active in the NPI Registry.
What does John C. Kortenber specialize in?
John C. Kortenber is an optometrist in Algona, Iowa. The primary specialty in the NPI Registry is Optometrist (taxonomy code 152W00000X).
Where does John C. Kortenber practice?
John Kortenber practices at 112 N Thorington St, Algona, IA 50511-2614. John Kortenber's primary practice is John C Kortenber Optometry Pc in Algona, Iowa. Dmand AI also links John Kortenber to 1 medical group.
What is John C. Kortenber's office phone number?
The practice phone on file for John Kortenber is (515) 395-3937.
What is John C. Kortenber's medical license number?
John Kortenber holds Missouri license 2002014339.
Does John C. Kortenber accept Medicare?
Yes. CMS lists John Kortenber as accepting Medicare assignment.
How many Medicare patients does John C. Kortenber see?
CMS counts 313 Medicare patients who saw John Kortenber in 2024, with an average age of 75.
Where did John C. Kortenber go to medical school?
John Kortenber graduated from University of Missouri St Louis - School of Optometry in 2001.
Has John C. Kortenber received payments from drug or device companies?
CMS Open Payments shows $32 in general payments to John Kortenber from 1 company from 2025 to 2025. The largest total came from LKC Technologies, Inc.
How long has John C. Kortenber been practicing?
John Kortenber graduated from medical school in 2001, 25 years ago.
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