Anatomical narrow angle, left eye

This code describes an anatomical variation in the left eye where the angle between the iris and cornea is unusually narrow, predisposing the patient to angle-closure glaucoma. This narrowness can impede the outflow of aqueous humor, leading to increased intraocular pressure.

This code is used when documentation indicates a narrow anterior chamber angle in the left eye, identified through gonioscopy or other imaging, without evidence of acute angle closure or glaucoma. It applies to prophylactic or monitoring encounters for this anatomical predisposition.

• Ensure documentation specifies "left eye" and "anatomical narrow angle" or similar descriptive terms.
• Do not confuse with codes for angle-closure glaucoma (H40.2x) or primary open-angle glaucoma (H40.1x).
• If both eyes have an anatomical narrow angle, use the appropriate bilateral (H40.033) or right eye (H40.031) codes in addition to or instead of this code.