Anatomical narrow angle, unspecified eye

This code describes a structural abnormality of the anterior chamber angle of the eye, where the iris is positioned unusually close to the trabecular meshwork. This narrowness can impede the outflow of aqueous humor, increasing the risk of angle-closure glaucoma. It indicates the presence of this anatomical predisposition without specifying laterality.

Assign this code when documentation confirms an anatomical narrow angle, but the specific eye (right or left) is not specified. This is typically identified during a comprehensive eye examination, often involving gonioscopy. Use when the patient presents for evaluation of this anatomical finding, even in the absence of elevated intraocular pressure or glaucoma.

• Do not use this code if the laterality (right or left eye) is documented; instead, select the more specific H40.031 or H40.032.
• This code represents a predisposition, not active glaucoma. If glaucoma is present, additional codes for the specific type and stage of glaucoma are required.
• Ensure documentation clearly states "anatomical narrow angle" or similar terminology indicating a structural finding, not merely a suspicion.