Start New EnglishEspañol中文РусскийالعربيةTiếng ViệtFrançaisDeutsch한국어Tagalog Library Performance
BETA v.3.0

2025 CPT code 66170

Trabeculectomy ab externo for glaucoma treatment in the absence of previous surgery.

This code is specific to cases with no previous surgery or scarring. For cases involving scarring, use 66172. Do not report this code with goniotomy (65820) or trabeculotomy ab externo (65850).

Modifiers such as -LT and -RT can be used to indicate the left or right eye, respectively. Modifier -50 is used for bilateral procedures. Other modifiers, as described in the CPT manual, might apply depending on the specific circumstances.

Medical necessity for this procedure must be established through documentation showing that the patient has uncontrolled glaucoma despite medical management, with risk of progressive vision loss if IOP is not lowered. Documentation of IOP measurements, visual field tests, and clinical findings supporting the diagnosis and need for surgical intervention is required.

The ophthalmologist prepares the patient, administers anesthesia, creates the scleral fistula, and removes a portion of the trabecular meshwork to enhance fluid drainage and lower intraocular pressure.

IMPORTANT:For trabeculectomy with scarring, use 66172. For trabeculotomy ab externo, use 65850.

In simple words: This eye surgery creates a new drainage channel to lower pressure inside the eye, helping to treat glaucoma. It's done when no previous eye surgery has been performed in the affected area.

This procedure involves creating a fistula (opening) in the sclera (white of the eye) and removing a part of the trabecular meshwork to facilitate drainage of aqueous humor and reduce intraocular pressure in glaucoma patients who have not undergone prior surgery in the same eye.

Example 1: A patient with uncontrolled open-angle glaucoma, despite maximum tolerated medical therapy, undergoes a trabeculectomy ab externo as the first surgical intervention to reduce intraocular pressure., A patient with angle-closure glaucoma requires surgical intervention to improve aqueous outflow. Due to the lack of prior surgery or significant scarring, 66170 is appropriate., A patient with secondary glaucoma resulting from trauma requires a trabeculectomy as no previous surgery has been performed on the affected eye to address the glaucoma.

Documentation should include the diagnosis of glaucoma, severity level, prior treatments, IOP measurements, medical necessity for surgery, operative report detailing the procedure, and post-operative instructions.

** Only Enterprise users with EHR integration can access case-specific answers. Click here to request access.

Discover what matters.

iFrame™ AI's knowledge is aligned with and limited to the materials uploaded by users and should not be interpreted as medical, legal, or any other form of advice by iFrame™.