Keratoprosthesis

POLICY NUMBER

A.9.03.01

DESCRIPTION

A keratoprosthesis, consisting of a central optic held in a cylindrical frame, is an artificial cornea intended to restore vision to patients with severe bilateral corneal disease for whom a corneal transplant is not an option. The keratoprosthesis replaces the cornea that has been removed and is held in place by the surrounding tissue. Various biologic materials are being investigated to improve integration of the prosthetic into the eye.

Cornea

The cornea, a clear, dome-shaped membrane that covers the front of the eye, is a key refractive element of sight. Layers of the cornea consist of the epithelium (outermost layer); Bowman layer; the stroma, which comprises approximately 90% of the cornea; Descemet membrane; and the endothelium.

Treatment

The established surgical treatment for corneal disease is penetrating keratoplasty, which involves making a large central opening through the cornea and then filling the opening with a full-thickness donor cornea. In certain conditions, such as Stevens-Johnson syndrome, ocular cicatricial pemphigoid, chemical injury, or prior failed corneal transplant, survival of transplanted cornea is poor. The keratoprosthesis was developed to restore vision in patients for whom a corneal transplant is not an option.

Keratoprosthetic devices consist of a central optic held in a cylindrical frame. The keratoprosthesis replaces the section of the cornea that has been removed, and, along with being held in place by the surrounding tissue, may be covered by a membrane to further anchor the prosthesis. A variety of biologic materials are being investigated to improve the integration of prosthetic corneal implants into the stroma and other corneal layers.

The Dohlman-Doane keratoprosthesis, most commonly referred to as the Boston Keratoprosthesis (KPro), is manufactured under the auspices of the Harvard Medical School affiliated Massachusetts Eye and Ear Infirmary. The Boston type I KPro uses a donor cornea between a central stem and a back plate. The Boston type 2 prosthesis is a modification of the type 1 prosthesis and is designed with an anterior extension to allow implantation through surgically closed eyelids. The AlphaCor, previously known as the Chirila keratoprosthesis (Chirila KPro), consists of a polymethylmethacrylate device with a central optic region fused to a surrounding sponge skirt; the device is inserted in a 2-stage surgical procedure.

Autologous keratoprostheses use a central polymethylmethacrylate optic supported by a skirt of either tibia bone or the root of a tooth with its surrounding alveolar bone. The most common is the osteo-odonto-keratoprosthesis, which uses osteodental lamina derived from an extracted tooth root and attached alveolar bone that has been removed from the patient’s jaw. Insertion of the osteo-odonto-keratoprosthesis device requires a complex staged procedure, in which the cornea is first covered with buccal mucosa. The prosthesis itself consists of a polymethylmethacrylate optical cylinder, which replaces the cornea, and is held in place by a biologic support made from a canine tooth extracted from the recipient. A hole is drilled through the dental root and alveolar bone, and the polymethylmethacrylate prosthesis is placed within. This entire unit is placed into a subcutaneous ocular pocket and is then retrieved 6 to 12 months later for final insertion.

Hydroxyapatite, with a similar mineral composition to both bone and teeth (phosphate and calcium), may also be used as a bone substitute and as a bioactive prosthesis with the orbit. Collagen coating and scaffolds have also been investigated to improve growth and biocompatibility with the corneal epithelial cells, which form the protective layer of the eye. Many of these materials and devices are currently being tested in vitro or in animal models.

In 1992, the Boston KPro (Dohlman-Doane keratoprosthesis; Massachusetts Eye and Ear Infirmary) was approved by the U.S. Food and Drug Administration (FDA) through the premarket approval process for use in patients with severe corneal opacity. The device is used when standard corneal transplant has failed or would be unlikely to succeed. There are 2 types of Boston KPro. Type 1 is used in eyes when eyelids, blink mechanism, and tear film are intact. Type 2 is used with severe dry eye and in eyes with mucosal keratinization and obliteration of normal conjunctival fornices.

In August 2002, the AlphaCor® (Chirila Keratoprosthesis) was cleared for marketing by the FDA through the 510(k) process. The FDA determined that this device was substantially equivalent to the Dolman-Doane keratoprosthesis. The AlphaCor® device is indicated as a keratoprosthesis in adults with corneal opacity when standard penetrating keratoplasty with donor tissue is not suitable, when patients have declined standard penetrating keratoplasty, or when adjunctive procedures to prevent graft rejection are contraindicated.

POLICY

The Boston (Dohlman-Doane) Keratoprosthesis (Boston KPro) may be considered medically necessary for the surgical treatment of severe corneal opacification in situations where cadaveric corneal transplants have failed or have a very low likelihood of success. Conditions under which cadaveric corneal transplants have a likelihood of failure include but are not limited to the following: 

• The cornea is severely opaque and vascularized; AND

• Best-corrected visual acuity is 20/400 or less in the affected eye and 20/40 or less in the contralateral eye; AND

• No end-stage glaucoma or retinal detachment is present; AND

• The individual has one of the following indications:

  • History of 1 or more corneal transplant graft failures

  • Stevens-Johnson syndrome

  • Ocular cicatricial pemphigoid

  • Autoimmune conditions with rare ocular involvement

  • Ocular chemical burns

  • An ocular condition unlikely to respond favorably to primary corneal transplant surgery (eg, libel stem cell compromise or postherpetic anesthesia).

Individuals should be able and expected to comply with postoperative care.

All other types of permanent keratoprostheses are considered investigational.

POLICY EXCEPTIONS

Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Implantation of a keratoprosthesis is considered a high-risk procedure associated with numerous complications and probable need for additional surgery. Therefore, the likelihood of regaining vision and the individual's visual acuity in the contralateral eye should be taken into account when considering the appropriateness of this procedure. Treatment should be restricted to centers experienced in treating this condition and staffed by surgeons adequately trained in techniques addressing implantation of this device.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

A.  consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

B.  appropriate with regard to standards of good medical practice; and

C.  not solely for the convenience of the Member, his or her Provider; and

D.  the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

7/15/2004: Approved by Medical Policy Advisory Committee (MPAC).

10/1/2004: Code Reference section completed.

5/24/2006: Policy reviewed, no changes.

9/25/2007: Policy reviewed, permanent keratoprostheses changed to investigational. Removed "Permanent keratoprostheses may be considered medically necessary in adult patients with corneal opacity not suitable for standard penetrating keratoplasty with donor tissues, or where donor tissue has been declined, or where adjunctive measures required to prevent graft rejection are medically contraindicated."

06/22/2010: Policy description updated regarding treatment approaches and FDA approval of devices. Policy statement revised to indicate that the Boston keratoprosthesis (Boston KPro) may be considered medically necessary for the treatment of corneal blindness when specific criteria are met, and to state that a permanent keratoprosthesis for all other conditions and all other types of permanent keratoprostheses are considered investigational. FEP verbiage added to the Policy Exceptions section. Deleted outdated references in the Sources section. All codes moved from non-covered to covered, and added HCPCS code L8609.

04/20/2011: Policy reviewed; no changes.

03/27/2012: Policy reviewed; no changes.

04/17/2013: Policy reviewed; no changes.

03/18/2014: Policy reviewed; no changes.

07/08/2015: Policy description updated regarding devices. Medically necessary policy statement updated to add the following conditions: 1) Best-corrected vision is ≤20/400 inthe affected eye and ≤20/40 in the opposite eye; AND 2) No end-stage glaucoma or retinal detachment is present; AND 3) The patient has one of the following indications: Multiple corneal transplant graft failures; Stevens-Johnson syndrome; Ocular cicatricial pemphigoid; Autoimmune conditions with rare ocular involvement; Ocular chemical burns;An ocular condition unlikely to respond favorably to primary corneal transplant surgery (eg, limbal stem cell compromise or postherpetic anesthesia).

08/27/2015: Code Reference section updated for ICD-10.

05/27/2016: Policy number A.9.03.01 added. Policy Guidelines updated to add medically necessary and investigative definitions.

07/12/2016: Policy description updated. Policy statement revised to state that the Boston (Dohlman-Doane) Keratoprosthesis (Boston KPro) may be considered medically necessary for the surgical treatment of severe corneal opacification in situations where cadaveric corneal transplants have failed or have a very low likelihood of success. Medically necessary criteria updated to change "vision" to "visual acuity" and "Multiple graft failures" to "History of 1 or more." Removed the following policy statement: A permanent keratoprosthesis for all other conditions is consideredinvestigational. Reworded statement regarding postoperative care.

03/28/2017: Policy description updated regarding devices. Medically necessary criteria updated to change "opposite" to "contralateral."

04/10/2018: Policy description updated. Policy statements unchanged.

04/05/2019: Policy reviewed; no changes.

04/16/2020: Policy reviewed; no changes.

06/10/2021: Policy reviewed. Policy statements unchanged. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity."

05/19/2022: Policy reviewed; no changes.

04/18/2023: Policy reviewed; no changes.

04/23/2024: Policy reviewed; no changes.

04/22/2025: Policy reviewed. Policy statements and Policy Guidelines updated to change "patients" to "individuals."

SOURCE(S)

Blue Cross Blue Shield Association policy # 9.03.01

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document. 

Covered Codes

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