Michael Korthals
Optometrist · Mason City, IANPI 1407880883
Payments from drug & device makers
Across 20 payments — averaging $20.48 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Bausch & Lomb, A Division Of Bausch Health US, LLC$245
- Optos, Inc.$61
- LKC Technologies, Inc.$45
- Alcon$21
- Bausch & Lomb Americas Inc.$15
- Novartis$12
- plus $11 from 1 others
What the payments were for
- Food & beverage$34985%
- Entertainment$6115%
Most of this is food and beverage — typically meals provided during product presentations at a clinic or hospital. Nationally that is the single largest category of reported payments by count.
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| Bausch & Lomb, A Division Of Bausch Health US, LLC | 12 | $245 |
| Optos, Inc. | 2 | $61 |
| LKC Technologies, Inc. | 2 | $45 |
| Alcon | 1 | $21 |
| Bausch & Lomb Americas Inc. | 1 | $15 |
| Novartis | 1 | $12 |
| Sun Pharmaceutical Industries Inc. | 1 | $11 |
How this compares
$410 in reported general payments places this provider in the 50th percentile of 559 optometrist providers in Iowa.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| LumiganBimatoprost | 103 | $49,204 |
| RestasisCyclosporine | 13 | $14,320 |
| CombiganBrimonidine Tartrate/Timolol | 26 | $9,064 |
| Alphagan PBrimonidine Tartrate | 26 | $9,059 |
| Brimonidine Tartrate | 15 | $3,163 |
| Latanoprost | 178 | $1,969 |
| Brimonidine Tartrate-TimololBrimonidine Tartrate/Timolol | 16 | $1,932 |
| Dorzolamide-TimololDorzolamide Hcl/Timolol Maleat | 41 | $1,511 |
| Tobramycin-DexamethasoneTobramycin/Dexamethasone | 22 | $1,072 |
| Prednisolone Acetate | 14 | $414 |
Paid to pharmacies, not to this prescriber.
Other optometrist in Mason City
- Warren PetersonIndianola$213K
- Sara ButterworthCoralville$191K
- Ethan HuismanWaukee$111K
- Kelsi SawatzkyWest Des Moines$26K
- Heidi BellClive$19K
- Jennifer DenhartogClive$16K
- Wendianne WilsonUrbandale$16K
- Daniel KoenigAmes$11K
- Lexie FranzeenWest Des Moines$7K
- Mallori PhillipsGrimes$7K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.