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Official Description

Collagen cross-linking of cornea, including removal of the corneal epithelium, when performed, and intraoperative pachymetry, when performed

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Collagen cross-linking of the cornea is a specialized ophthalmic procedure aimed at enhancing the structural integrity of the cornea by strengthening the collagen fibers within it. This is achieved through the application of riboflavin, also known as Vitamin B2, in conjunction with ultraviolet-A (UV-A) light. The procedure is particularly beneficial for patients suffering from conditions such as keratoconus, pellucid marginal degeneration, and ectasia that may arise following LASIK surgery. By increasing the number of fiber anchors that bond collagen together, collagen cross-linking serves as a first-line treatment option to stabilize the cornea and prevent further progression of these conditions. Additionally, this technique may be employed to address corneal ulcers and infections, as well as to secure Intacs, which are small plastic discs implanted within the cornea to improve its shape. During the procedure, the patient is positioned reclining, and a lid speculum is utilized to keep the eyelids open. Anesthetic eye drops are administered to ensure patient comfort. The procedure may involve the removal of a thin layer of corneal epithelium to facilitate quicker absorption of riboflavin, although it can also be performed as a transepithelial procedure with the epithelium intact. The riboflavin solution is applied at specific intervals until it is detected in the anterior chamber of the eye, confirmed by a blue filter on a slit lamp. Following this, UV-A light is directed at the corneal apex for a predetermined duration to initiate the cross-linking process. Post-treatment, ultrasound pachymetry may be conducted to assess the corneal thickness, and antibiotic eye drops are applied, followed by the placement of a bandage contact lens to aid in recovery.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The procedure of collagen cross-linking of the cornea is indicated for several specific conditions and symptoms, which include:

  • Keratoconus - A progressive eye disease where the cornea thins and bulges into a cone shape, leading to distorted vision.
  • Pellucid Marginal Degeneration - A condition characterized by thinning of the cornea, typically occurring in the lower part, which can cause irregular astigmatism.
  • Ectasia caused by LASIK - A complication that can occur after LASIK surgery, where the cornea becomes unstable and begins to bulge outward.
  • Corneal ulcers - Open sores on the cornea that can result from infections or other conditions, which may benefit from the strengthening of corneal structure.
  • Corneal infections - Infections that compromise the integrity of the cornea, where cross-linking may help in stabilizing the corneal tissue.
  • Bonding of Intacs - The use of collagen cross-linking to secure Intacs, which are small plastic devices implanted in the cornea to improve its shape and vision.

2. Procedure

The procedure of collagen cross-linking involves several critical steps that ensure its effectiveness and safety. Each step is designed to prepare the cornea for the treatment and to facilitate the cross-linking process.

  • Step 1: Patient Preparation - The patient is positioned in a reclining chair, and a lid speculum is placed to keep the eyelids open during the procedure. Anesthetic eye drops are instilled to numb the eye and enhance patient comfort throughout the treatment.
  • Step 2: Pachymetry Measurement - Ultrasound pachymetry may be performed to measure the pre-treatment thickness of the cornea. This measurement is crucial for assessing the cornea's condition and determining the appropriate treatment plan.
  • Step 3: Epithelium Removal (if applicable) - A thin layer of corneal epithelium may be removed to allow for more rapid absorption of riboflavin. Alternatively, the procedure can be conducted as a transepithelial procedure, where the epithelium remains intact.
  • Step 4: Riboflavin Application - Riboflavin eye drops are instilled at measured intervals. The application continues until riboflavin is detected in the anterior chamber of the eye, which is confirmed using a blue filter on a slit lamp.
  • Step 5: UV-A Light Application - After sufficient riboflavin absorption, UV-A light is applied to the corneal apex for a prescribed duration. This exposure initiates the cross-linking process, strengthening the collagen fibers within the cornea.
  • Step 6: Post-Treatment Pachymetry - Following the UV-A light application, ultrasound pachymetry may be performed again to measure the post-treatment thickness of the cornea, ensuring that the procedure has been effective.
  • Step 7: Post-Procedure Care - Antibiotic eye drops are instilled to prevent infection, and a bandage contact lens is applied to protect the cornea during the initial healing phase.

3. Post-Procedure

After the collagen cross-linking procedure, patients are typically monitored for any immediate complications. The application of antibiotic eye drops helps to reduce the risk of infection, while the bandage contact lens provides protection and comfort as the cornea heals. Patients may experience some discomfort, light sensitivity, or blurred vision in the days following the procedure, which is generally expected. Follow-up appointments are essential to assess the healing process and to ensure that the cornea is recovering properly. The overall recovery time can vary, but many patients notice improvements in their vision as the cornea stabilizes and heals over the following weeks.

Short Descr COLGN CRS-LINK CRN&PACHYMTRY
Medium Descr COLLAGEN CROSS-LINKING CORNEA&PACHYMTRY
Long Descr Collagen cross-linking of cornea, including removal of the corneal epithelium, when performed, and intraoperative pachymetry, when performed
Status Code Carriers Price the Code
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 0 - No payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Office-based surgical procedure added to ASC list in CY 2008 or later without MPFS nonfacility PE RVUs; payment based on OPPS relative payment weight.
Berenson-Eggers TOS (BETOS) P4E - Eye procedure - other
MUE 2
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
CR Catastrophe/disaster related
GA Waiver of liability statement issued as required by payer policy, individual case
GC This service has been performed in part by a resident under the direction of a teaching physician
GX Notice of liability issued, voluntary under payer policy
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
Date
Action
Notes
2023-01-01 Changed First appearance of change(s) in codebook.
2022-07-01 Changed Code description changed
2022-07-01 Note Guideline Added
2020-01-01 Changed First appearance of change in code book.
2019-07-01 Changed Code description changed.
2019-01-01 Changed Code description changed.
2016-01-01 Added Added
Code
Description
Code
Description
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