Disclaimer

Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract.  Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage.  Medical technology is constantly changing, and we reserve the right to review and update our policies periodically.

Description

Intrastromal corneal ring segments consist of micro-thin soft plastic inserts of variable thickness that are placed in the periphery of the cornea. Intrastromal corneal ring segments have been investigated as a means of improving vision in diseases such as keratoconus and for refractive surgery to correct mild myopia.

Intrastromal corneal ring segments are flexible, crescent-shaped rings of polymethylmethacrylate that are placed in the periphery of the cornea. An incision is made in the cornea and channels are created in it by rotating a lamellar dissector or by using a femtosecond laser. One or two corneal implant segments are introduced to each channel, and various implants with a range of implant thicknesses are available for different degrees of correction. They affect refraction in the eye by physically changing the shape of the cornea (flattening the front of the eye), thereby correcting the irregular corneal shape. If required, the implants can be removed at a later date.

In myopia, intrastromal inserts correct myopia by flattening the center of the cornea and represent an alternative to laser in situ keratomileusis (LASIK) and other refractive surgeries. The proposed advantages of the intrastromal corneal rings are that their insertion does not affect the central cornea and thus their effect is not related to the healing process in the cornea. No corneal tissue is removed, and the implants are reversible.

Keratoconus is a progressive bilateral dystrophy that is characterized by paracentral steepening and stromal thinning that impairs visual acuity. Initial treatment often consists of hard contact lenses. A penetrating keratoplasty (i.e., corneal grafting) is the next line of treatment in patients who develop intolerance to contact lenses. While visual acuity is typically improved with keratoplasty, perioperative complications are an associated risk; long-term topical steroid use is required; and endothelial cell loss occurs over time, which is a particular concern in younger patients. As an alternative, a variety of keratorefractive procedures have been attempted, broadly divided into subtractive and additive techniques. Subtractive techniques include photorefractive keratectomy or LASIK, but in general results of these techniques have been poor. Implantation of intrastromal corneal ring segments represents an additive technique in which the implants are intended to reinforce the cornea, prevent further deterioration, and potentially obviate the need for a penetrating keratoplasty. This technique has primarily been investigated in patients in whom the cornea has remained transparent and who are intolerant of contact lenses.

INTACS® represent an intrastromal corneal ring that has received approval by the U.S. Food and Drug Administration (FDA) for 2 indications.

In 1999, INTACS were approved through a premarket approval process (PMA) for the following labeled indication:

“The KeraVision Intacs are intended for the reduction or elimination of mild myopia (-1.00 to -3.00 diopters spherical equivalent at the spectacle plane) in patients:

In 2004, INTACS received an additional FDA approval through the humanitarian device exemption (HDE) process for the following indication:

“This device is indicated for the reduction or elimination of myopia and astigmatism in patients with keratoconus, who are no longer able to achieve adequate vision with their contact lenses or spectacles, so that their functional vision may be restored and the need for a corneal transplant procedure may potentially be deferred. The specific set of keratoconic patients proposed to be treated with INTACS prescription inserts are those patients:

• Who have experienced a progressive deterioration in their vision, such that they can no longer achieve adequate functional vision on a daily basis with their contact lenses or spectacles;
• Who are 21 years of age or older;
• Who have clear central corneas;
• Who have a corneal thickness of 450 microns or greater at the proposed incision site; AND
• Who have corneal transplantation as the only remaining option to improve their functional vision.”
  

Note: HDE does not require the manufacturer to provide data confirming the efficacy of the device, but rather data supporting its “probable” benefit. The HDE process is available for devices treating conditions that affect fewer than 4,000 Americans per year.

Policy

Implantation of intrastromal corneal ring segments may be considered medically necessary for the treatment of keratoconus in patients 21 years of age or older who meet the following criteria:

Implantation of intrastromal corneal ring segments is considered not medically necessary as a treatment of myopia.

Implantation of intrastromal corneal ring segments is considered investigational for all other conditions.

Policy Guidelines

Benefit Application

Rationale

Myopia

The FDA approval for the INTACS device was based on results of a multi-institutional study involving 361 subjects with mild myopia. (1) Subsequently, the 2-year results of this study were published in the peer- reviewed literature. (2) These data suggested that the intrastromal rings predictably and effectively reduced or eliminated mild myopia (-1.00 to -3.00 diopter) and that the refractive effect was stable over time. However, mild myopia is effectively treated with either spectacles or contact lenses. Therefore, this application of intrastromal corneal implants is considered not medically necessary. In addition, as noted in the Benefits Applications section, many plan benefits or contracts contain a specific exclusion for refractive eye surgeries.

Keratoconus

The published data regarding intrastromal corneal implants for keratoconus consist of single institution case series, with the largest case series including 74 subjects. (3-5) Boxer Wachler and colleagues reported on the outcomes in 74 eyes of 50 subjects with a mean follow-up of 9 months. (3) A total of 45% gained at least 2 lines of best spectacle corrected visual acuity (BSCVA), 51% of patients had no change, and 4% lost BSCVA. Siganos and colleagues studied 33 eyes in 26 patients at a mean follow-up of 11.3 months. (4) In this study, 25 eyes recorded a 1- to 6-line gain in BSCVA, while 4 eyes remained unchanged and 4 eyes experienced a loss. Colin and colleagues reported the 1-year results in a series of 10 patients. (5) The mean values for BSCVA improved progressively over time, and at the 12-month follow-up, average visual acuity was 2 lines better than baseline.

These data are inadequate to permit scientific conclusions due to the small number of patients and the limited follow-up of 1 year. The long-term outcomes, and the key outcome of whether or not the use of the inserts will significantly delay or obviate the need for a corneal transplant, cannot be evaluated.

2006 Update

A literature search was performed for the period of 2005 through January 2006. No additional published articles were identified that would prompt reconsideration of the policy statement, which remains unchanged.

2006 Updates

A number of studies have been published since the prior update. These are all case series without control groups. From the published studies a number of findings can be summarized:

And finally, alternative approaches (laser) are being used to place this type of ring. (11).

While these studies reflect ongoing evaluation, they still do not adequately address long-term outcomes, and the question of an impact on and need for corneal transplants is unknown.

2007-2008 Update
A search of the MEDLINE database was performed for the period of January 2007 through December 2007.
Colin and Malet reported 2-year follow-up from a prospective, single-center European study in 100 keratoconic eyes (82 consecutive patients) with Intacs implantation. (12) Patients had been referred for a PKP procedure due to contact lens intolerance for correction of myopia and irregular astigmatism. Intacs were removed from 4 eyes (4%) due to poor visual outcome or extrusion, and 14 were lost to follow-up. Of the 82 remaining eyes (68 patients), both corrected and uncorrected visual acuity remained relatively stable between 1- and 2-years follow-up. Central corneal thickness decreased from 478 microns pre-operatively to 434 microns at 1 year and 421 microns at 2 years. The authors note that this may have resulted from slight stretching of the corneal tissue by the segments rather than a disease-related progressive thinning of the cornea. Histopathology from 8 eyes who had PKP after removal of Intacs inserts revealed keratocyte apoptosis. (13) The authors note that further study is needed to determine whether Intacs accelerate corneal thinning and keratoconus progression.
Another study reported 5-year follow-up on 28 patients (36 eyes) who had initially participated in a clinical trial for safety and efficacy of Intacs implantation in keratoconic patients. (14) In 5 patients (7 eyes), the Intacs segments were removed due to patient’s dissatisfaction. An additional 8 patients (12 eyes) were unable to attend follow-up appointments. Five-year follow-up was reported for the remaining 17 eyes (59%). Refractive stability was obtained at the 6-month follow-up (spherical equivalent error at baseline -5.54 to -2.68 at six months) and remained stable throughout the 5-year follow-up (-3.02). With the exception of one eye that had a decrease of 3 lines, the best-corrected visual acuity was maintained to the pre-Intacs level. Keratometric values showed a mean reduction of 1.57 D (49.59 to 48.02 diopters).
2009 Update

An updated literature search for the period of January 2008 through August 2009 was performed using the MEDLINE database. The search identified a number of case reports of adverse events following implantation of intrastromal corneal ring segments, including bacterial keratitis, fungal keratitis, corneal edema, deep corneal vascularization, descemet detachment, and alterations of extracellular matrix components and proteinases.

Clinical Input Received through Physician Specialty Societies and Academic Medical Centers

In response to requests, input was received through one Physician Specialty Society and 3 Academic Medical Centers while this policy was under review. While the various Physician Specialty Societies and Academic Medical Centers may collaborate with and make recommendations during this process, through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the Physician Specialty Societies or Academic Medical Centers, unless otherwise noted. The input agreed that implantation of intrastromal corneal ring segments may be considered medically necessary for selected patients with keratoconus when the only other option for improving visual acuity is corneal transplantation. The input agreed that implantation of intrastromal corneal ring segments is not medically necessary as a treatment of myopia.

Summary

Clinical input strongly supports the use of intrastromal corneal ring segments in a select group of patients with advanced keratoconus whose only other option for restoration of visual function is the more invasive penetrating keratoplasty. Although questions remain regarding the impact of this procedure on long-term health outcomes, the risk of adverse events is decreased in comparison with the existing alternative (corneal transplant), and there is a potential (as yet unproven) to delay the need for the more invasive procedure. Therefore, the policy statement has been changed. Use of intrastromal corneal ring segments may be considered medically necessary in patients who meet the FDA-HDE criteria for use of this device.

Technology Assessments, Guidelines and Position Statements

The United Kingdom’s National Institute for Health and Clinical Excellence (NICE) issued guidance in 2007 on corneal implants for keratoconus. (15) The guidance, based on 9 case series, one non- randomized controlled trial and specialist advisors’ opinion concluded that “current evidence on the safety and efficacy of corneal implants for keratoconus appears adequate to support the use of this procedure provided that normal arrangements are in place for consent, audit and clinical governance.”

Medicare National Coverage
No national coverage determination

References:

1. www.fda.gov/cdrh/pdf/p980031b.pdf
2. Schanzlin DJ, Abbott RL, Asbell PA et al. Two-year outcomes of intrastromal corneal ring segments for the correction of myopia. Ophthalmology 2001; 108(9):1688-94.
3. Boxer Wachler BS, Christie JP, Changra NS et al. Intacs for keratoconus. Ophthalmology 2003; 110(5):1031-40.
4. Siganos CS, Kymionis GD, Kartakis N et al. Management of keratoconus with Intacs. Am J Ophthalmology 2003; 135(1):64-70.
5. Colin J, Cochener B, Savary G et al. INTACS inserts for treating keratoconus: one-year results. Ophthalmology 2001; 108(8):1409-14.
6. Alio JL, Shabayek MH, Belda JI, et al. Analysis of results related to good and bad outcomes of Intacs implantation for keratoconus correction. J Cataract Refract Surg 2006; 32:756-61.
7. Colin J. European clinical evaluation: use of Intacs for the treatment of keratoconus. J Cataract Refract Surg 2006; 32:747-55.
8. Levinger S, Pokroy R. Keratoconus managed with intacs: one-year results. Arch Opthalmol 2005; 123:1308-14.
9. Kanellopoulos AJ, Pe LH, Perry HD et al. Modified intracorneal ring segment implantations (INTACS) for the management of moderate to advance keratoconus” efficacy and complications. Cornea 2006; 25:29-33.
10. Alio JL, Shabayek MH, Artola A. Intracorneal ring segments for keratoconus correction: long-term follow-up. J Cataract Refract Surg 2006; 32:978-85.
11. Rabinowitz YS, Li X, Ignacio TS et al. INTACS inserts using the femtosecond laser compared to the mechanical spreader in the treatment of keratoconus. J Refract Surg 2006; 22:764-71.
12. Colin J, Malet FJ. Intacs for the correction of keratoconus: two-year follow-up. J Cataract Refract Surg 2007; 33(1):69-74.
13. Samimi S, Leger F, Touboul D et al. Histopathological findings after intracorneal ring segment implantation in keratoconic human corneas. J Cataract Refract Surg 2007; 33(2):247-53.
14. Kymionis GD, Siganos CS, Tsiklis NS et al. Long-term follow-up of Intacs in keratoconus. Am J Ophthalmol 2007; 143(2):236-44.
15. National Institute for Health and Clinical Excellence (NICE). Guidance on corneal implants for keratoconus. July 2007. Available at: http://www.nice.org.uk/nicemedia/pdf/IPG227guidance.pdf Last viewed August 2009.

Index

Policy History