Corneal ectasia, left eye

This code represents a non-inflammatory thinning and bulging of the cornea in the left eye, leading to an irregular corneal shape. This ectasia results in distorted vision due to altered refractive power and can progress over time. It encompasses conditions like keratoconus, pellucid marginal degeneration, and post-LASIK ectasia affecting the left eye.

Use this code when documentation clearly indicates corneal ectasia affecting the left eye. This diagnosis is typically made through slit-lamp examination, corneal topography, and pachymetry. Ensure the medical record specifies "left eye" to support the laterality.

• Always confirm laterality (left, right, or bilateral) from the physician's documentation.
• Distinguish from corneal degeneration (H18.5-) which may not involve ectasia.
• If the specific type of ectasia (e.g., keratoconus) is documented, consider using a more specific code from the H18.7- subcategory if available and supported.