12 Different Glaucoma ICD 10 Codes - How and When to Use Them

Jun 24, 2021
5 min read

Understanding the nuances of glaucoma ICD-10 codes provides a mechanism for us to articulate why we may adjust our treatment and follow-up protocols. It also allows us to describe to a payer the reason we may be providing higher levels of service and performing more tests.

Important differences between ICD-10 codes

As I will describe below, there is a large variance in the cost of care between different types of glaucoma and different levels of glaucoma severity. Without the ability for us to articulate (through ICD-10 codes) these nuances, it leaves payers blind to the reasons that one provider may cost them more than another provider. Even when multiple patients are managed by the same provider, if we didn’t have a mechanism to describe the differences between patients, payers would not easily understand why some patients get more care and some need less.

For the cases below, you can follow along with the American Glaucoma Society severity classifications.

Let’s consider the first patient example

This patient has very early progressive mild retinal nerve fiber layer defects in the right eye with no visual field defects in either eye and is classified as having primary open angle glaucoma in the right eye with mild severity. This patient requires only one medication to maintain glaucoma control and is only seen two times per year. Additionally, the optometrist performs a visual field and an optic OCT one time per year and gonioscopy every other year.

Contrast this first case with a second patient example

The same optometrist is managing another patient who has severe bilateral low tension glaucoma with extensive optic nerve atrophy and visual field defects, who requires three medications and surgical intervention for glaucoma. This patient is seen quarterly and has at least two visual field tests per year, along with gonioscopy, optic nerve OCT, and optic nerve photos annually.

Without classification in ICD-10, claims-based data can’t identify the nuances of each case.

If both of these patients were described as unclassified glaucoma, payers would be unable to distinguish if the services provided to each of these patients was medically indicated without reviewing every chart. If the optometrist uses as much specificity as possible, they could help the payer understand the differences between each case and likely prevent unnecessary audits performed by the payer to confirm medical necessity of testing and follow-up care.

The 12 most relevant ICD-10 codes for glaucoma

Let’s review the 12 most relevant ICD-10 codes for patients with glaucoma with staging categories.

Besides my clinical experience I wanted to break down this list in a descending order based on a few rules.

  1. It is important to think about the list in terms of more common to less common, so I will present more common conditions before less common conditions.
  2. To be complete, I will include both unilateral and bilateral codes in the list.
  3. When staging the disease severity we will add one of the following staging codes where an underscore “_” exists for the seventh digit.
    • 0 - Stage unspecified
    • 1 - Mild stage
    • 2 - Moderate stage
    • 3 - Severe stage
    • 4 - Indeterminate stage
Diagnosis ICD-10 Code
Primary open angle glaucoma, right eye H40.111_
Primary open angle glaucoma, left eye H40.112_
Primary open angle glaucoma, bilateral H40.113_
Low-tension glaucoma, right eye H40.121_
Low-tension glaucoma, left eye H40.122_
Low-tension glaucoma, bilateral H40.123_
Pigmentary glaucoma, right eye H40.131_
Pigmentary glaucoma, left eye H40.132_
Pigmentary glaucoma, bilateral H40.133_
Capsular glaucoma, right eye H40.141_
Capsular glaucoma, left eye H40.142_
Capsular glaucoma, bilateral H40.143_

Now we can accurately describe to a payer the different patient encounters.

  • In the first case we had a patient with mild primary open angle in the right eye. Using the above classification we would describe the case with the code H40.1111.
  • In the second case we had a patient with severe low-tension glaucoma in both eyes. Using the above classification we would describe the case with the code H40.1233.

Choose the right code

Choosing the appropriate glaucoma ICD-10 code helps articulate the complexity of the case and justifies the coding level.

First and foremost, it is important to note that we include the specific detail in our assessment and plan so that we provide the most accurate picture of our encounter with a specific patient. In doing so it provides us with a clear path to justify past decisions and make future decisions.

Secondarily, by adding the appropriate specificity of the case it will allow us to code our encounters more appropriately based on our specific documentation for a specific patient to tell the story more clearly to the payer.

Check out our other content for documentation guidelines from the AMA related to coding level.

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About Christopher Wolfe, OD, FAAO, Dipl. ABO

Dr. Christopher Wolfe is a graduate of Northeastern State University Oklahoma College of Optometry. While in school, he served as president of the American Optometric Student Association, where he represented over 6,000 members. He is currently the Chair of the …

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