When managing chronic diseases in eye care, it’s not uncommon for patients to be on multiple medications, whether topical, systemic or both—many of which may cause ocular sequelae. You yourself will likely prescribe long-term medications for conditions such as glaucoma and dry eye. Knowing the rules in the ICD-10 hierarchy to code properly in both of these situations is crucial for getting paid when managing these patients.

Laundry List of Codes

When long-term medications are mentioned in eye care, most think about macular disease associated with Plaquenil (hydroxychloroquine, Sanofi-Aventis)—coded using Z79.899 – other long term (current) drug therapy. However, coding for these situations goes far beyond this one code. Here are the following categories specified by the ICD-10 for long-term medication use, under the heading of long term (current) drug therapy (Z79):

• Z79.0 – long-term (current) use of anticoagulants and antithrombotics/antiplatelets.
• Z79.01 – long-term (current) use of anticoagulants.
• Z79.02 – long-term (current) use of antithrombotics/antiplatelets.
• Z79.1 – long-term (current) use of non-steroidal anti-inflammatories.
• Z79.2 – long-term (current) use of antibiotics.
• Z79.3 – long-term (current) use of hormonal contraceptives.
• Z79.4 – long-term (current) use of insulin.
• Z79.5 – long-term (current) use of steroids.
• Z79.51 – long-term (current) use of inhaled steroids.
• Z79.52 – long-term (current) use of systemic steroids.
• Z79.81 – long-term (current) use of agents affecting estrogen receptors and estrogen levels.
• Z79.810 – long-term (current) use of selective estrogen receptor modulators (serms).
• Z79.811 – long-term (current) use of aromatase inhibitors.
• Z79.818 – long-term (current) use of other agents affecting estrogen receptors and estrogen levels.
• Z79.82 – long-term (current) use of aspirin.
• Z79.83 – long-term (current) use of bisphosphonates.
• Z79.84 – long-term (current) use of oral hypoglycemic drugs.
• Z79.891 – long-term (current) use of opiate analgesic.
• Z79.899 – other long-term (current) drug therapy.

Any number of these will likely crop up as you treat patients over their lifetime. In a dry eye practice, for example, it may be typical to see that the use of hormonal agents—Z79.81—is a causative factor in the dry eye disease process. Another good example is diabetes care; for this common disease, it is important to note in your list of diagnoses if the patient is taking insulin by using the ICD-10 code Z79.4. 

The Right Code in Sight

Often, long-term medical therapy comes in two categories in optometry: (1) long-term treatment for an ocular condition such as dry eye or glaucoma, and (2) ocular side effects of long-term systemic therapy. While ODs are well-versed in coding the former, some may be less comfortable with the latter. When coding for side effects of systemic therapy, you must first communicate with the care provider who prescribed the medication to discuss the underlying systemic condition being treated. This will help you better understand the clinical picture and the therapy options available. 

From there, follow these steps when coding any ocular condition that may be caused or exacerbated by the use of systemic medications:

1. Code the systemic disease. This is the primary diagnosis.
2. Code the ocular sequelae caused by the medication.
3. Code the proper long-term use of the medication based on the list of possible codes. Remember, ICD-10 requires you to be as specific as possible, so don’t fall into the habit of always using Z79.899 just because it’s easier.

These basic rules should allow you to always accurately describe, in ICD-10 terms, the conditions the patient presents with. Accuracy and attention to detail will ensure you are reimbursed properly and have fewer claim rejections.

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