Hypotony of left eye due to ocular fistula

This code signifies abnormally low intraocular pressure (IOP) in the left eye, specifically caused by an abnormal communication or tract (fistula) that allows aqueous humor to leak from the eye. This leakage leads to a sustained reduction in the eye's internal pressure.

Apply this code when documentation clearly indicates hypotony of the left eye and explicitly states that an ocular fistula is the underlying cause. This often follows trauma, surgery, or inflammatory conditions that create an abnormal drainage pathway.

• Ensure the documentation specifies the left eye; laterality is crucial for this code.
• Distinguish from hypotony due to other causes (e.g., H44.41- for hypotony due to dehydration).
• Code the underlying cause of the ocular fistula (e.g., trauma, surgical complication) if known and documented, following sequencing guidelines.