Filamentary keratitis, bilateral

This code represents a condition characterized by the presence of fine, thread-like strands of epithelial cells and mucus adhering to the corneal surface in both eyes. These filaments are typically attached at one end and move with blinking, causing foreign body sensation, pain, and photophobia. It is often associated with chronic dry eye or other ocular surface disorders.

Use this code when documentation clearly indicates the diagnosis of filamentary keratitis affecting both eyes. Supporting documentation should describe the presence of corneal filaments and specify the bilateral involvement. This diagnosis is often made via slit-lamp examination.

• Ensure the documentation explicitly states "bilateral" involvement; otherwise, a unilateral code may be more appropriate.
• Consider coding any underlying conditions, such as severe dry eye (e.g., H04.12-), that may be contributing to the filamentary keratitis.
• Differentiate from other forms of keratitis (e.g., punctate, ulcerative) where filaments are not the primary characteristic.