Crystal's MCW Coder HubCPT 66991: Extracapsular cataract removal with insertion of intraocular lens prosthesis, with insertion of anterior segment aqueous drainage device
Code Description
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Long Title: Extracapsular cataract removal with insertion of intraocular lens prosthesis (1-stage procedure), manual or mechanical technique (eg, irrigation and aspiration or phacoemulsification); with insertion of intraocular (eg, trabecular meshwork, supraciliary, suprachoroidal) anterior segment aqueous drainage device, without extraocular reservoir, internal approach, one or more.
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Short Title: ROUTINE CATARACT W/IOL & DRAIN
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Explanation: This is a combination code used when a surgeon performs a routine cataract extraction (phacoemulsification) with the placement of an intraocular lens (IOL) and, during the same operative session, implants one or more Minimally Invasive Glaucoma Surgery (MIGS) micro-stents (e.g., iStent inject, Hydrus) into the trabecular meshwork. The cataract removal must be standard/routine; if complex techniques (like iris hooks or Trypan blue for a mature cataract) are required, code 66989 would be used instead.
Reimbursement & Work Details
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wRVU: ~7.53 (Work Relative Value Units, subject to standard annual MPFS adjustments)
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Global Period: 090 Days (Major surgical procedure)
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Assistant Payable: No (Medicare generally restricts assistant surgeon payment for cataract and MIGS combination procedures).
ICD-10-CM / Diagnosis Code(s)
CRITICAL REQUIREMENT: Medical necessity for CPT 66991 requires dual diagnoses to support both components of the surgery: one for the cataract and one for the glaucoma.
1. Glaucoma Diagnoses (Required for the MIGS portion):
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H40.11- (Primary open-angle glaucoma): FDA-approved MIGS devices implanted during cataract surgery are almost exclusively indicated for mild-to-moderate Primary Open-Angle Glaucoma (POAG).
2. Cataract Diagnoses (Required for the Cataract portion):
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H25.- (Age-related cataract)
HCC Information:
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Yes, the POAG diagnoses (H40.11-) often map to Hierarchical Condition Categories (HCCs) for risk adjustment, especially in Medicare Advantage models.
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Cataract codes (H25.-) generally do not map to HCCs.
Bundling & NCCI Edits
Includes (Incidental/Bundled into 66991):
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All standard elements of routine cataract extraction (incisions, phacoemulsification, aspiration, IOL insertion).
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Intraoperative gonioscopy required to visualize the angle and place the MIGS device.
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Insertion of one or more drainage stents during the same operative session in the same eye.
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Use of ophthalmic viscoelastic devices (OVDs).
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90 days of routine postoperative care.
Exclusives / Mutually Exclusive (Cannot be billed with 66991):
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66989: Complex cataract surgery with anterior segment drainage device. (Mutually exclusive; choose routine or complex).
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66984: Routine cataract surgery without MIGS. (66991 replaces 66984 when a stent is added).
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0191T: Insertion of anterior segment aqueous drainage device, without concurrent cataract surgery (Standalone MIGS).
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65820: Goniotomy. (Often bundled by NCCI when performed on the same eye at the same session as a trabecular stent, as both target the trabecular meshwork).
Coding Tree & Hierarchy
MS-DRG (Medicare Severity Diagnosis Related Group)
While typically performed in an Outpatient/Ambulatory Surgery Center (ASC) setting, if performed inpatient, it maps to:
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MS-DRG 124: Other Disorders of the Eye with MCC.
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MS-DRG 125: Other Disorders of the Eye without MCC.
Coding Examples & Scenarios
Scenario 1: Routine Phacoemulsification with iStent
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Documentation: “Patient presents with mild primary open-angle glaucoma and a visually significant nuclear sclerotic cataract in the right eye. A clear corneal incision was made. The anterior capsule was opened with a continuous curvilinear capsulorrhexis. The lens was phacoemulsified without complication, and a single-piece acrylic IOL was placed in the capsular bag. Next, the patient’s head was repositioned, and under gonioscopic view, two iStent inject W devices were implanted into the trabecular meshwork. Viscoelastic was removed, and the eye was sealed.”
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Coding:
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CPT: 66991-RT
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ICD-10 1: H40.1111 (Primary open-angle glaucoma, right eye, mild stage)
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ICD-10 2: H25.11 (Age-related nuclear cataract, right eye)
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Explanation: The cataract removal was routine (no special devices or dyes needed for extraction), and the iStent placement requires the combination code 66991. You cannot code 66984 and a separate stent code.
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Scenario 2: Routine Phacoemulsification with Hydrus Microstent
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Documentation: “Patient with moderate POAG and a cortical cataract in the left eye. Routine phacoemulsification was performed, and a posterior chamber IOL was securely placed. Following lens implantation, the anterior chamber was refilled with cohesive viscoelastic. Using a surgical gonioprism, the trabecular meshwork was visualized, and a Hydrus Microstent was advanced into Schlemm’s canal spanning 3 clock hours. The device was confirmed to be in good position. Incisions were hydrated.”
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Coding:
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CPT: 66991-LT
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ICD-10 1: H40.1122 (Primary open-angle glaucoma, left eye, moderate stage)
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ICD-10 2: H25.012 (Age-related cortical cataract, left eye)
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Explanation: The Hydrus Microstent is another FDA-approved anterior segment drainage device. Combined with a standard cataract extraction, 66991 is the only correct code to report the entire service.
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