Medical policy: Keratoprosthesis and Corneal Surgery (Formerly Corneal Surgery)

Policy number: MP 9.011

Effective date: 9/1/2026

Policy

Keratoprosthesis

The Boston (Dohlman-Doane) Keratoprosthesis (Boston KPro) may be considered medically necessary for the surgical treatment of severe corneal opacification under the following conditions in situations where cadaveric corneal transplants have failed or have a very low likelihood of success (See Policy Guidelines)::

Other Corneal Surgery

Corneal surgery for the correction of astigmatism resulting from trauma or from previous surgery (e.g., cataract, corneal) may be considered medically necessary. The astigmatism in the latter situation is considered a complication of the initial surgery.

Policy guidelines

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.

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 vision is ≤20/400 in the affected eye and ≤20/40 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 (e.g., limbal stem cell compromise or post herpetic anesthesia).

Note that individuals should be expected to be able to be compliant with postoperative care.

Cross-References:

• MP 1.044 Implantation of Intrastromal Corneal Ring Segment
• MP 2.028 Eye Care
• MP 5.062 Computer Assisted Corneal Topography
• MP 6.031 Gas Permeable Scleral Contact Lens and Therapeutic Soft Contact Lens

Product variations

This policy is only applicable to certain programs and products administered by Capital Blue Cross and subject to benefit variations. Please see additional information below.

FEP PPO - Refer to FEP Medical Policy Manual. The FEP Medical Policy Manual can be found at: FEP Medical Policy Manual.

Description/Background

Keratoprostheses

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.

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 1 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 (PMMA) 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 PMMA 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 PMMA optical cylinder, which replaces the cornea, and is held in place by biologic support made from a canine tooth extracted from the recipient. A hole is drilled through the dental root and alveolar bone, and the PMMA 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 animal models.

Corneal Surgery (Refractive Keratoplasty)

Refractive keratoplasty is a generic term that includes all surgical procedures on the cornea to improve vision by changing the refractive index of the corneal surface. Refractive keratoplasties include the following surgeries:

• Radial Keratotomy (RK) is a surgical correction for myopia (nearsightedness). Using a high-powered microscope, the physician places microincisions (usually eight or fewer) on the surface of the cornea in a pattern much like the spokes of a wheel. The incisions are very precise in terms of depth, length, and arrangement. The microincisions allow the central cornea to flatten, thus reducing the convexity of the cornea, which produces an improvement in vision.
• Photorefractive Keratectomy (PRK) uses a computerized laser to correct myopia (nearsightedness). The excimer laser is utilized for cornea reshaping as it removes tiny amounts of tissue to produce the results needed to correct nearsightedness. The excimer laser produces a beam of ultraviolet light in pulses that last only a few billionths of a second. Each pulse removes a microscopic amount of tissue by evaporating it, producing very little heat, and usually leaving underlying tissue almost untouched. Overall, the surgery takes approximately 10–20 minutes; however, the use of the laser beam lasts only 15–40 seconds.
• Automated Lamellar Keratoplasty (ALK) can correct hyperopia. For the treatment of moderate farsightedness, the cornea is opened across the top to form a type of “cap,” using an automated instrument. When the “cap” is positioned back into its original location on top of the eye, microscopic scar tissue is formed, causing the “cap” to bulge out, thus correcting the overly flattened cornea that is associated with hyperopia. Almost like Velcro, the cornea and “cap” adhere to each other, eliminating the need for sutures. Normally, one eye is treated at a time, with about 3 to 4 weeks allowed between each eye surgery. To ease any discomfort, the eye is anesthetized with special drops, and the patient is given a mild sedative to remain relaxed and aware throughout the procedure.
• Minimally Invasive Radial Keratotomy (mini-RK) is intended in cases of myopia, to alter the cornea’s shape and consequently the refraction by reducing the millimeters of cornea that are incised.

All the above procedures can be used alone or in combination to produce the optimal result for a given patient.

• Keratomileusis involves removing, freezing, and lathing the patient’s cornea, followed by its replacement onto the corneal bed. This surgery has been proposed for myopia and aphakic hyperopia (aphakia is the absence of the lens of the eye).
• Keratophakia involves removing the patient’s cornea followed by placement of a lathed donor cornea beneath the recipient’s cornea, which is then reattached. This surgery has been proposed for aphakic hyperopia.
• Epikeratophakia (lamellar keratoplasty) involves suturing a pre-lathed donor cornea onto the surface of the recipient’s cornea. This surgery has been proposed as a means of correcting adult and pediatric aphakia, keratoconus (a conical protrusion of the cornea, caused by thinning of the stroma, and resulting in major changes in the refractive power of the eye), and myopia.

Regulatory Status

In 1992, the Boston KPro (Dohlman-Doane keratoprosthesis; Massachusetts Eye and Ear Infirmary) was approved by the U.S. Food and Drug Administration 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 Food and Drug Administration through the 510(k) process. The Food and Drug Administration determined that this device was substantially equivalent to the Dohlman-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.

FDA product code: HQM

Rationale

Summary of Evidence

For individuals who have corneal blindness and have failed or are not candidates for corneal transplantation who receive a Boston Keratoprosthesis (Boston KPro), the evidence includes case series and systematic reviews. Relevant outcomes are change in disease status, morbid events, quality of life, and treatment-related morbidity. Numerous case series have been published. Together, studies have assessed thousands of eyes. A 2015 systematic review of Boston KPro efficacy included 22 studies with a total of 2176 eyes. Systematic reviews and case series with longer follow-up (i.e., at least 2 years) have shown improvement in visual outcomes in a substantial percentage of patients with Boston KPro. This procedure is high-risk and associated with numerous complications (e.g., the growth of retroprosthetic membranes) and a probable need for additional surgery, thus careful patient selection is important. The evidence is sufficient to determine that the technology results in an improvement in the net health outcome.

For individuals who have corneal blindness and have failed or are not candidates for corneal transplantation who receive a keratoprosthesis using the AlphaCor device, the evidence includes case series. Relevant outcomes are change in disease status, morbid events, quality of life, and treatment-related morbidity. Only a few published case series have evaluated the AlphaCor device. There is insufficient data on improvement in vision outcomes using the AlphaCor device. Moreover, the device has been associated with complications, including thinning, or melting of the anterior corneal surface and corneal necrosis. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals who have corneal blindness and have failed or are not candidates for corneal transplantation who receive an osteo-odonto-keratoprosthesis, the evidence includes case series and a systematic review. Relevant outcomes are change in disease status, morbid events, quality of life, and treatment-related morbidity. A 2012 systematic review of case series, all conducted outside of the United States, found high anatomic survival rates at 5 and 20 years, but vision outcomes were not well-described. Osteo-odonto-keratoprosthesis is a complex surgical procedure and has been associated with a number of complications, including extrusion of the keratoprosthesis, retinal detachment, and vitreoretinal complications. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Definitions

N/A

Disclaimer

Capital Blue Cross’ medical policies are used to determine coverage for specific medical technologies, procedures, equipment, and services. These medical policies do not constitute medical advice and are subject to change as permitted by law or applicable clinical evidence from independent treatment guidelines. Treating providers are solely responsible for medical advice and treatment of members. These policies are not a guarantee of coverage or payment. Payment of claims is subject to a determination regarding the member’s benefit program and eligibility on the date of service, and a determination that the services are medically necessary and appropriate. Final processing of a claim is based upon the terms of contract that applies to the member’s benefit program, including benefit limitations and exclusions. If a provider or a member has a question concerning this medical policy, please contact Capital Blue Cross’ Provider Services or Member Services.

Coding information

Note: This list of codes may not be all-inclusive, and codes are subject to change at any time. The identification of a code in this section does not denote coverage as coverage is determined by the terms of member benefit information. In addition, not all covered services are eligible for separate reimbursement.

Covered when Medically Necessary

Covered when Medically Necessary for Keratoprostheses:

Medically Necessary for Diagnosis for Keratoprostheses:

References

Corneal Surgery

1. TEC Assessment 1988, pp. 14, 169, 177, 197
2. TEC Assessment 1986, p. 97
3. American Academy of Ophthalmology Quality of Care Secretariat, Hoskins Center for Quality Eye Care Summary Recommendations for Keratorefractive Laser Surgery - updated June 2013

Keratoprosthesis

1. Lee WB, Shtein RM, Kaufman SC, et al. Boston Keratoprosthesis: Outcomes and Complications: A Report by the American Academy of Ophthalmology. Ophthalmology. Jul 2015; 122(7): 1504-11. PMID 25934510
2. Ahmad S, Mathews PM, Lindsley K, et al. Boston Type 1 Keratoprosthesis versus Repeat Donor Keratoplasty for Corneal Graft Failure: A Systematic Review and Meta-analysis. Ophthalmology. Jan 2016; 123(1): 165-77. PMID 26545318
3. Colinio JB, Belin MW, Todani A, et al. Retention of the Boston keratoprosthesis type 1: multicenter study results. Ophthalmology. Jun 2013; 120(6): 1195-200. PMID 23499061
4. Rudnisky CJ, Belin MW, Guo R, et al. Visual Acuity Outcomes of the Boston Keratoprosthesis Type 1: Multicenter Study Results. Am J Ophthalmol. Feb 2016; 162: 89-98.e1. PMID 26550696
5. Srikumaran D, Munoz B, Aldave AJ, et al. Long-term outcomes of boston type 1 keratoprosthesis implantation: a retrospective multicenter cohort. Ophthalmology. Nov 2014; 121(11): 2159-64. PMID 25017414
6. Rudnisky CJ, Belin MW, Todani A, et al. Risk factors for the development of retroprosthetic membranes with Boston keratoprosthesis type 1: multicenter study results. Ophthalmology. May 2012; 119(5): 951-5. PMID 22361316
7. Dunlap K, Chak G, Aquavella JV, et al. Short-term visual outcomes of Boston type 1 keratoprosthesis implantation. Ophthalmology. Apr 2010; 117(4): 687-92. PMID 20096462
8. Odoric S, Haas W, Gilmore MS, et al. Fungal Infections After Boston Type 1 Keratoprosthesis Implantation: Literature Review and In Vitro Antifungal Activity of Hypochlorous Acid. Cornea. Dec 2015; 34(12): 1599-605. PMID 26488624
9. Chan CC, LoVerde L, Qiang J, et al. Incidence, Risk Factors, and Surgical Management of Boston Type 1 Keratoprosthesis Corneal Melts, Leaks, and Extrusions. Cornea. Aug 2016; 35(8): 1049-56. PMID 27391092
10. Goldman DR, Hubschman JP, Aldave AJ, et al. Postoperative posterior segment complications in eyes treated with the Boston type I keratoprosthesis. Retina. Mar 2013; 33(3): 532-41. PMID 23073339
11. Hicks CR, Crawford GJ, Lou X, et al. Corneal replacement using a synthetic hydrogel cornea, AlphaCor: device, preliminary outcomes and complications. Eye (Lond). Apr 2003; 17(3): 385-92. PMID 12724702
12. Crawford GJ, Hicks CR, Lou X, et al. The Chirila Keratoprosthesis: phase I human clinical trial. Ophthalmology. May 2002; 109(5): 883-9. PMID 11986092
13. Hoffart L, Carles G, Matonti F. Lamellar corneal lenticule graft to treat keratolysis after AlphaCor keratoprosthesis implantation. Eur J Ophthalmol. 2015; 25(1): 1-7. PMID 25198171
14. Tan A, Tan DT, Tan XW, et al. Osteo-odonto keratoprosthesis: systematic review of surgical outcomes and complication rates. Ocul Surf. Jan 2012; 10(1): 15-25. PMID 22330056
15. Falcinelli G, Falsini B, Taloni M, et al. Modified osteo-odonto-keratoprosthesis for treatment of corneal blindness: long-term anatomical and functional outcomes in 181 cases. Arch Ophthalmol. Oct 2005; 123(10): 1379-29. PMID 16219722
16. Michael R, Charoenrook V, de la Paz MF, et al. Long-term functional and anatomical results of osteo- and osteodonto-keratoprosthesis. Graefes Arch Clin Exp Ophthalmol. Aug 2008; 246(8): 1133-7. PMID 18491123
17. Hughes EH, Mokete B, Ainsworth G, et al. Vitreoretinal complications of osteoodontokeratoprosthesis surgery. Retina. Oct 2008; 28(8): 1138-45. PMID 18779721
18. Farid M, Rhee MK, Akpek EK, et al. Corneal Edema and Opacification Preferred Practice Pattern®. Ophthalmology. Jan 2019; 126(1): P216-P285. PMID 30366795
19. American Academy of Ophthalmology Cornea/External Disease Panel. Preferred Practice Pattern: Corneal Edema and Opacification. San Francisco, CA: American Academy Ophthalmology; 2023
20. Joffe, Mark MD. Moderate and severe thermal burns in children: Emergency Management. Up To Date, last updated Sep 30, 2025. Literature review February 2026.