H18.61 Keratoconus, stable

Name of the Condition

• Keratoconus, stable (ICD Code: H18.61)

Summary

Keratoconus, stable, refers to a non-progressive form of keratoconus where the cornea has thinned and bulged into a cone-like shape but is not actively worsening. This condition results in distorted vision due to irregular astigmatism, though the structural changes remain stable over time. It typically affects both eyes asymmetrically and may require ongoing management to maintain visual function.

Causes

The exact cause of keratoconus is not fully understood, but it is thought to involve a combination of genetic predisposition, environmental factors, and hormonal influences. Some cases may be associated with systemic conditions or eye trauma, though many occur without a clear underlying trigger. In the stable phase, the corneal changes have ceased progressing, but the underlying structural abnormalities persist.

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 visual acuity tests evaluate the extent of vision impairment. The stability of the condition is confirmed by comparing current findings with prior examinations to ensure no progression over time.

Treatment Options

Treatment focuses on correcting vision and managing symptoms. Options include eyeglasses or soft contact lenses for mild cases, rigid gas permeable lenses for more advanced distortion, and specialty lenses like scleral lenses for severe irregular astigmatism. In some cases, corneal cross-linking may be considered to strengthen the cornea, though this is more common in progressive keratoconus. Surgical interventions, such as corneal transplantation, are reserved for cases with significant vision loss.

Prognosis and Follow-Up

The prognosis for stable keratoconus is generally good, as the condition does not worsen over time. However, regular follow-up appointments are essential to monitor for any signs of progression and adjust treatment as needed. Most patients maintain functional vision with appropriate correction, though some may experience gradual changes requiring lens updates or additional interventions.

Complications

While stable keratoconus does not progress, complications can arise from the underlying corneal changes. These include severe visual distortion, difficulty fitting contact lenses, and increased risk of corneal scarring or hydrops (fluid accumulation in the cornea) if the condition becomes unstable. In rare cases, advanced disease may lead to corneal transplantation.

Lifestyle & Prevention

To prevent exacerbation, avoid eye rubbing, as this can worsen corneal damage. Protect the eyes from injury and UV light, and manage underlying allergies or systemic conditions that may contribute to eye irritation. Regular eye exams help detect any changes early, ensuring timely intervention if progression occurs.

When to Seek Professional Help

Seek medical attention if vision worsens suddenly, if eye pain or redness develops, or if contact lenses become increasingly uncomfortable or difficult to wear. These symptoms may indicate progression or complications requiring prompt evaluation.

Tips for Medical Coders

Document the stability of the condition clearly in the medical record, as this distinguishes H18.61 from progressive keratoconus codes. Include details on corneal topography results, pachymetry measurements, and any prior progression assessments to support the stable classification. Ensure the diagnosis is confirmed by a specialist, and note the absence of recent changes in corneal shape or vision over the monitoring period.