2026 ICD-10-CM Diagnosis Code H18.609Keratoconus, unspecified, unspecified eye
ICD-10-CM Codes›H00–H59›H15-H22›H18
- Billable — Valid for Submission
- Not Chronic
H18.609 is a billable ICD-10-CM diagnosis code for keratoconus, unspecified, unspecified eye. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 124 through 125. Coders also document this condition as acute hydrops keratoconus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cornea and external disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute hydrops keratoconus
- Keratoconus
- Posterior keratoconus
- Rizzutti sign
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Keratoconus
a noninflammatory, usually bilateral protrusion and thinning of the cornea, the apex being displaced downward and nasally. it occurs most commonly in females at about puberty. two closely related noninflammatory corneal ectasias are pellucid marginal degeneration and keratoglobus.Cornea
the transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous corneal epithelium; bowman membrane; corneal stroma; descemet membrane; and mesenchymal corneal endothelium. it serves as the first refracting medium of the eye. it is structurally continuous with the sclera, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the trigeminal nerve via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (cline et al., dictionary of visual science, 4th ed)Keratoconus
a degenerative, structural disorder of the eye, characterized by a cone-shaped protrusion of the cornea. it may lead to visual disturbances.
Patient EducationClinical
Corneal Disorders
Your cornea is the outermost layer of your eye. It is clear and shaped like a dome. The cornea helps to shield the rest of the eye from germs, dust, and other harmful matter. It also helps your eye to focus. If you wear contact lenses, they float on top of your corneas.
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Convert H18.609 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About H18.609Overview
Is H18.609 (Keratoconus, unspecified) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report keratoconus, unspecified, unspecified eye on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does H18.609 group to?
When keratoconus, unspecified, unspecified eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 124, 125, with relative weights from 0.7678 to 1.3231 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of H18.609?
Under the General Equivalence Mappings, keratoconus, unspecified, unspecified eye converts to ICD-9-CM 371.60 (keratoconus NOS). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
