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  • Savvy Coder

    Coding ICD-10 for Cornea

    By Sue Vicchrilli, COT, OCS, Academy Director of Coding and Reimbursement, and Jenny Edgar, CPC, CPCO, OCS, Academy Coding Specialist
    Cornea/External Disease

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    It’s true. When it comes to the cornea (with the exception of dystrophies), there are 3 ICD-10 codes for every ICD-9 code. You’ll find these codes in chapter 7 of ICD-10; look for the section titled Disorders of Sclera, Cornea, Iris, and Ciliary Body (H15-H22).

    Code for Laterality

    Except for dystrophies, corneal ICD-10 codes have a digit for laterality:

    • 1 for the right eye
    • 2 for the left eye
    • 3 for both eyes.

    Example. If you’re coding for exposure keratoconjunctivitis, you would use H16.211 if the condition is present in the right eye, H16.212 if in the left, and H16.213 if in both.

    Tip. For nonelectronic superbills, you can represent all lateralities with a single line—e.g., H16.21 1 2 3. (So, for example, if the diagnosis was exposure keratoconjunctivitis of the left eye, you would circle the 2—H16.21 1 2 3.)

    Some Commonly Used Codes

    In these examples, report laterality by replacing the dash with a 1, 2, or 3.

    There are 7 types of scleritis:

    H15.00- Unspecified scleritis
    H15.01- Anterior scleritis
    H15.02- Brawny scleritis
    H15.03- Posterior scleritis
    H15.04- Scleritis with corneal involvement
    H15.05- Scleromalacia perforans
    H15.09- Other scleritis

    There are 3 types of episcleritis:

    H15.10- Unspecified episcleritis
    H15.11- Episcleritis periodica fugax
    H15.12- Nodular episcleritis

    And there are 8 types of ulcers:

    H16.00- Unspecified corneal ulcer
    H16.01- Central corneal ulcer
    H16.02- Ring corneal ulcer
    H16.03- Corneal ulcer with hypopyon
    H16.04- Marginal corneal ulcer
    H16.05- Mooren’s corneal ulcer
    H16.06- Mycotic corneal ulcer
    H16.07- Perforated corneal ulcer

    Tip. If you are using a nonelectronic superbill, it is best to identify the types of diagnoses that are seen most frequently and add them—rather than adding all options—to the superbill. If you’re using EHRs, see if your EHR system will allow the practice’s physicians to establish libraries of their most frequently seen diagnoses.


    ICD-10’s section for hereditary corneal dystrophies lists 7 conditions. Each has only 1 code; no laterality is needed.

    H18.50 Unspecified hereditary corneal dystrophies
    H18.51 Endothelial corneal dystrophy (Fuchs’ dystrophy)
    H18.52 Epithelial (juvenile) corneal dystrophy
    H18.53 Granular corneal dystrophy
    H18.54 Lattice corneal dystrophy
    H18.55 Macular corneal dystrophy
    H18.59 Other hereditary corneal dystrophies

    Excludes1 Notes

    Excludes1 Notes flag conditions that can’t be billed in the same eye at the same patient encounter. For example, M35.01 Sjögren’s syndrome isn’t payable with H16.22 Keratoconjunctivitis sicca. Similarly, H1.21 Acute toxic conjunctivitis is not payable with T26- Burn and corrosion confined to eye and adnexa.

    Injury and Trauma

    T15.0- Corneal foreign body, T15.1- Conjunctival foreign body, and T26.1- Burn of cornea and conjunctival sac must be submitted as 7-character codes, with the final character being an A (if an initial encounter), D (subsequent encounter), or S (sequela). As these codes are listed as 5-character codes (with the 5th character indicating laterality), an X must act as a placeholder in the 6th position so that A, D, or S can be added as the 7th character (e.g., T15.01XA).

    More Online

    A cornea ICD-10 reference guide, along with guides for other subspecialties, can be found at Thanks to David B. Glasser, MD, for his contribution to this resource.