Summary & Overview
CPT 66175: Aqueous Outflow Canal Expansion with Stent
CPT code 66175 denotes a surgical ophthalmology procedure that expands the eye’s aqueous outflow (drainage) canal and includes placement of a device or stent to relieve intraocular pressure. This procedure is clinically important in managing glaucoma and other conditions where impaired aqueous drainage leads to elevated intraocular pressure and risk of vision loss. Nationally, use of implantable drainage-support techniques is growing as surgeons adopt minimally invasive approaches aimed at reducing medication burden and improving pressure control.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides comparative benchmarks on utilization and reimbursement trends for CPT code 66175, summarizes relevant policy updates affecting coverage and prior authorization, and situates the code within clinical care pathways for glaucoma management. Readers will find concise explanations of coding scope and typical settings of care (ambulatory surgical centers and hospital outpatient departments), plus guidance on where this procedure fits relative to other glaucoma interventions. Data limitations: Data not available in the input for payer-specific rates, ICD-10 pairings, and associated taxonomies.
Billing Code Overview
CPT code 66175 describes a surgical procedure in which the provider expands the eye's aqueous outflow (drainage) canal to relieve intraocular pressure. The procedure includes placement of a device or stent left in place to maintain or enhance drainage.
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Service type: Surgical ophthalmology procedure to improve aqueous outflow
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Typical site of service: Ambulatory surgical center or hospital outpatient setting
Clinical & Coding Specifications
Clinical Context
A typical patient is a 65-year-old with progressive primary open-angle glaucoma poorly controlled on maximally tolerated medical therapy, presenting with elevated intraocular pressure (IOP) and documented optic nerve/visual field progression. After diagnostic evaluation including slit-lamp exam, gonioscopy, IOP measurements, optical coherence tomography (OCT) of the optic nerve, and visual field testing, the ophthalmologist elects an ab interno canaloplasty or trabecular micro-bypass procedure that expands the aqueous outflow canal and leaves a permanent stent in place to lower IOP.
Preoperative workflow includes informed consent, medication reconciliation, topical antisepsis, local or monitored anesthesia care, and marking of laterality. The procedure is typically performed in an outpatient ambulatory surgery center or hospital outpatient department. Postoperative care includes topical antibiotics and corticosteroids, IOP checks the same day and during the early postoperative period, and adjustments to glaucoma medications as pressure improves. Clinical documentation should include baseline IOP, optic nerve and visual field status, indication for surgical intervention, laterality, device placement details, and postoperative plan.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the physician component separate from the technical facility charge for diagnostics if applicable. |