H18.62 Keratoconus, unstable

Name of the Condition

• Keratoconus, unstable (ICD Code: H18.62)

Summary

Keratoconus, unstable, is a progressive eye disorder where the cornea thins and bulges into a cone-like shape, leading to distorted vision. The term "unstable" indicates that the condition is actively progressing or has a tendency to worsen over time. This structural change disrupts the cornea's normal curvature, causing irregular astigmatism and visual impairment.

Causes

The exact cause of keratoconus is not fully understood but is believed to involve a combination of genetic, environmental, and hormonal factors. It often begins during adolescence and may progress due to chronic eye rubbing, allergies, or underlying systemic conditions. Some cases occur without a clear trigger.

Risk Factors

• Family history of keratoconus
• Chronic eye rubbing or irritation
• Allergic conditions (e.g., atopic dermatitis, asthma)
• Certain connective tissue disorders (e.g., Ehlers-Danlos syndrome)
• Down syndrome

Symptoms

• Blurred or distorted vision
• Increased sensitivity to light and glare
• Frequent changes in eyeglass or contact lens prescriptions
• Difficulty seeing at night or in low light
• Eye strain or headaches

Diagnosis

Diagnosis involves a comprehensive eye examination, including slit-lamp microscopy to assess corneal shape and clarity. Corneal topography is used to map the cornea's curvature and detect irregularities. Pachymetry measures corneal thickness, and additional tests may evaluate visual acuity and refractive errors.

Treatment Options

• Eyeglasses or soft contact lenses for mild cases
• Rigid gas permeable contact lenses for advanced cases
• Corneal collagen cross-linking to strengthen the cornea
• Intacs, small corneal inserts, to reshape the cornea
• Corneal transplant for severe cases

Prognosis and Follow-Up

With early diagnosis and appropriate management, progression can be slowed or stabilized. Regular follow-up appointments are essential to monitor changes in corneal shape and vision. Treatment may need adjustment as the condition evolves.

Complications

• Severe vision loss if untreated
• Corneal scarring
• Increased risk of corneal hydrops (swelling)
• Difficulty fitting contact lenses

Lifestyle & Prevention

• Avoid rubbing the eyes, especially if prone to allergies
• Use lubricating eye drops to reduce irritation
• Protect eyes from trauma or injury
• Follow up with an eye care professional regularly

When to Seek Professional Help

Seek immediate care if you experience sudden vision changes, increased eye pain, or signs of corneal swelling. Regular check-ups are recommended for those with risk factors or a family history of keratoconus.

Tips for Medical Coders

Document the instability of keratoconus clearly in the medical record, as this distinguishes it from stable or unspecified forms. Ensure the diagnosis is supported by clinical findings, such as corneal topography or slit-lamp examination results, to justify the use of code H18.62.