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MP 9.03.14 Implantation of Intrastromal Corneal Ring Segments

Original Policy Date
Last Review Status/Date
Reviewed with literature search/9:2013
  Return to Medical Policy Index


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. 


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 pellucid marginal degeneration, 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.

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 laser in situ keratomileusis (LASIK), but in general, results of these techniques have been poor. In deep anterior lamellar keratoplasty, pathologic corneal stromal tissue is selectively removed to the level of the Descemet membrane; followed by transplantation of a donor graft. 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.

Pellucid marginal degeneration is a noninflammatory progressive degenerative disease, typically characterized by bilateral peripheral thinning (ectasia) of the inferior cornea. Deterioration of visual function results from the irregular astigmatism induced by asymmetric distortion of the cornea, and visual acuity typically cannot be restored by using spherocylindrical lenses. Rigid gas permeable contact lenses may be used to treat pellucid marginal degeneration. Intracorneal ring segment implantation, crescentic lamellar keratoplasty, penetrating keratoplasty, and corneal wedge excision have also been proposed.

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.

Regulatory Status

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

In 1999, INTACS inserts 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:

  • Who are 21 years of age or older;
  • With documented stability of refraction as demonstrated by a change of less than or equal to 0.50 diopter for at least 12 months prior to the preoperative examination; and
  • Where the astigmatic component is +1.00 diopter or less.”

In 2004, INTACS received an additional approval by the FDA 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.

Intrastromal corneal ring devices available outside of the U.S. include:


Ferrara intrastromal corneal ring segment (ICRS)

Keraring intrastromal corneal ring segments (ICRS)

MyoRing intracorneal continuous ring (ICCR)


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:

  • The patient has experienced a progressive deterioration in their vision, such that they can no longer achieve adequate functional vision with contact lenses or spectacles; AND
  • Corneal transplantation is the only alternative to improve their functional vision; AND
  • The patient has a clear central cornea with a corneal thickness of 450 microns or greater at the proposed incision site.

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

In July 2005, the following CPT category III code was introduced:

0099T: Implantation of intrastromal corneal ring segments

Benefit Application
BlueCard/National Account Issues

Some Plan benefits or contracts may include an exclusion for refractive eye surgery that would apply to the use of intrastromal corneal ring segments as a treatment of mild myopia.

State or federal mandates (e.g., FEP) may dictate that all devices approved by the U.S. Food and Drug Administration (FDA) may not be considered investigational, and thus these devices may be assessed only on the basis of their medical necessity.


This policy was created in 2005 and has since been updated periodically using the MEDLINE database. The most recent literature update was performed for the period of August 2012 through August 13, 2013.

Literature Review


Approval by the U.S. Food and Drug Administration (FDA) for the INTACS® device was based on the results of a multi-institutional study involving 361 subjects with mild myopia. Subsequently, the 2-year results of this study were published in the peer-reviewed literature. (1) 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 INTACS 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.


The published data regarding INTACS for keratoconus consists primarily of single institution case series. These case series indicate that a substantial proportion of patients with keratoconus treated with this system have improved vision at up to 5-year follow-up. Most studies have reported improvements (in uncorrected or corrected visual acuity) in 75% to 80% of patients in whom changes in 2–3 lines of corrected or uncorrected visual acuity were considered success. (2-5) Approximately 10% of patients required a second procedure because of an unsatisfactory initial result. (3, 6)

For example, in 2007 Colin and Malet reported 2-year follow-up from a prospective, single-center European study in 100 eyes with keratoconus (82 consecutive patients) and INTACS implantation. (7) Patients had been referred for a penetrating keratoplasty procedure due to contact lens intolerance for correction of myopia and irregular astigmatism. INTACS inserts were removed from 4 eyes (4%) due to poor visual outcome or extrusion, and 14 eyes 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.

Several retrospective studies have reported stable vision at up to 5 years after INTACS implantation. Bedi et al. evaluated the risk of keratoconus progression in a study of 105 consecutive eyes (85 patients) that had undergone INTACS implantation. (8) At 1-year follow-up, 1 eye had extrusion, and 12 (11.4%) had undergone removal of INTACS because of unsatisfactory results; these eyes were managed by penetrating or deep lamellar keratoplasty. Of the 105 eyes, 80% retained the INTACS implant and showed no keratoconus progression over 5 years of follow-up. Vega-Estrada et al. reported that in a series of 51 eyes, the improvement in vision obtained at 6 months after INTACS implantation was maintained out to 5 years postoperatively, although this study only included cases without significant changes in corneal topography over the 12 months before surgery. (9)

Kymionis et al. 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 patients with keratoconus. (10) In 5 patients (7 eyes), the INTACS segments were removed due to patient dissatisfaction. Five-year follow-up was reported for 17 eyes (59%). Refractive stability was obtained at the 6-month follow-up (spherical equivalent error at baseline -5.54 to -2.68 at 6 months) and remained stable throughout the 5-year follow-up (-3.02).

One retrospective study compared outcomes between intrastromal corneal ring segments (Keraring, n=30) and deep anterior lamellar keratoplasty (DALK, n=36) in patients with advanced keratoconus. (11) One eye in the DALK group was converted to penetrating keratoplasty and was not included in the analysis. At 24 months’ follow-up, compared to preoperatively, the DALK group had significantly greater improvement in uncorrected and corrected distance visual acuity and significantly greater reduction in spherical equivalent, manifest cylinder, and K values. The uncorrected distance visual acuity improved by at least 1 line in all eyes in the DALK group. In the intrastromal corneal ring segment group, uncorrected distance visual acuity improved in 24 (80%) eyes, remained unchanged in 3 (10%) eyes, and decreased in 3 (10%) eyes.

Ongoing randomized clinical trials are evaluating combined treatment with INTACS and corneal collagen cross-linking to slow the progression of keratoconus (see policy No. 9.03.28 Corneal Collagen Cross-Linking).

Astigmatism after Penetrating Keratoplasty

Several case series from Europe and South America have been identified in which intrastromal ring segments have been implanted for the correction of residual astigmatism after penetrating keratoplasty. In one of the studies 9 patients received intrastromal ring segments (Kerarings) for high astigmatism (greater than 4 diopters) after penetrating keratoplasty. (12) Mean keratometry decreased 4.17 diopters (from 46.28 to 42.11). Of the 9 patients, 1 reported night halos, and 2 had the implant removed due to compulsive eye rubbing and vascularization in the stromal tunnel. The authors noted that in patients with a corneal transplant with a diameter of 7.5 mm or smaller, INTACS intrastromal ring segments should not be used because the segments would be close to the graft-host junction.

Pellucid Marginal Degeneration

In 2009, Pinero and colleagues published a European multicenter retrospective analysis of 21 consecutive eyes in 15 patients with intrastromal corneal ring implantation (3 INTACS and 18 Kerarings) for pellucid marginal degeneration who had reduced best-corrected visual acuity and/or contact lens intolerance or dissatisfaction. (13) At 6 months after surgery, uncorrected visual acuity had not changed; 17% of eyes lost lines of best-corrected visual acuity, and 44% of eyes gained 2 lines or greater of best-corrected visual acuity. Ring explantation was performed in 4 eyes (19%) due to visual deterioration during the follow-up. Mean keratometry decreased 1.76 diopters, from 44.95 diopters to 43.19 diopters at 6-months postoperatively.

A 2010 publication from Europe reported a retrospective analysis of intrastromal ring segment implantation (210-degree arc length Keraring) in 16 consecutive eyes of 10 patients with pellucid marginal degeneration who had reduced best-corrected visual acuity and dissatisfaction with spectacle and contact lens-corrected vision. (14) At 12 months after implantation, uncorrected visual acuity improved from 1.69 logMAR to 0.83 logMAR. At the 36 month follow-up, patients (n=11) had gained a mean of 2.4 lines uncorrected visual acuity and 3.3 lines of spectacle-corrected visual acuity. There was a statistically significant reduction in manifest spherical refraction from -2.43 diopters to -0.72 diopters. For the 11 patients who completed 36-month follow-up, there was no significant change in outcome measures between 12 and 36 months. No intraoperative or postoperative complications were noted aside from white deposits around the segments in 1 patient.

Adverse events

Updated literature searches have identified a number of case reports of adverse events following implantation of intrastromal corneal ring segments, including persistent pain, extrusion, traumatic shattering, bacterial keratitis, fungal keratitis, corneal edema, deep corneal vascularization, Descemet membrane’s detachment, and alterations of extracellular matrix components and proteinases. In a multicenter series of 251 intrastromal corneal ring segment implantations, 58 eyes of 47 patients had the devices explanted. (15) The main cause was found to be extrusion (48%), followed by poor refractive outcome (38%), keratitis (7%), and corneal melting and perforation (7%). The time from implantation to explantation ranged from 0.1 to 82 months.

In another study, 6 of 20 eyes had “significant” postoperative problems with regards to thinning and ring exposure, and a dense corneal infiltrate developed in 1 patient at 7 months. (16) Histopathologic examination of 8 eyes that underwent penetrating keratoplasty after removal of INTACS inserts revealed keratocyte apoptosis. (17) Further study long-term is needed to determine whether INTACS reduce or accelerate corneal thinning and progression of keratoconus.

Ongoing Clinical Trials

A search of online site in August 2013 identified 2 large randomized trials on the treatment of keratoconus with combined use of intrastromal corneal ring segments and collagen cross-linking. A Phase II/III randomized trial (NCT01081561) will compare corneal collagen cross-linking in eyes with INTACS compared to eyes without INTACS. The study has an estimated enrollment of 400 subjects with estimated completion in 2015. Another Phase III trial (NCT01112072) will randomly assign subjects to receive collagen cross-linking immediately after, or 3 months after, INTACS implantation. Estimated enrollment is 160 subjects, with an estimated completion date of December 2014.

Clinical Input Received through Physician Specialty Societies and Academic Medical Centers

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.

In response to requests, input was received through 1 physician specialty society and 3 academic medical centers while this policy was under review in 2009. The input considered implantation of intrastromal corneal ring segments to be 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.


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, use of intrastromal corneal ring segments may be considered medically necessary in patients who meet the FDA-humanitarian device exemption (HDE) criteria for use of this device.

There is insufficient evidence to evaluate health outcomes in patients with pellucid marginal deterioration. Therefore, intrastromal corneal ring segments in this population are considered investigational.

Practice 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. (18) The guidance, based on 9 case series, 1 nonrandomized 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

There is no national coverage determination.





  1. 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.
  2. 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(5):756-61.
  3. Colin J. European clinical evaluation: use of Intacs for the treatment of keratoconus. J Cataract Refract Surg 2006; 32(5):747-55.
  4. Siganos CS, Kymionis GD, Kartakis N et al. Management of keratoconus with Intacs. Am J Ophthalmol 2003; 135(1):64-70.
  5. Boxer Wachler BS, Christie JP, Chandra NS et al. Intacs for keratoconus. Ophthalmology 2003; 110(5):1031-40.
  6. Levinger S, Pokroy R. Keratoconus managed with intacs: one-year results. Arch Ophthalmol 2005; 123(10):1308-14.
  7. Colin J, Malet FJ. Intacs for the correction of keratoconus: two-year follow-up. J Cataract Refract Surg 2007; 33(1):69-74.
  8. Bedi R, Touboul D, Pinsard L et al. Refractive and topographic stability of Intacs in eyes with progressive keratoconus: five-year follow-up. J Refract Surg 2012; 28(6):392-6.
  9. Vega-Estrada A, Alio JL, Brenner LF et al. Outcomes of intrastromal corneal ring segments for treatment of keratoconus: Five-year follow-up analysis. J Cataract Refract Surg 2013; 39(8):1234-40.
  10. Kymionis GD, Siganos CS, Tsiklis NS et al. Long-term follow-up of Intacs in keratoconus. Am J Ophthalmol 2007; 143(2):236-44.
  11. Ozerturk Y, Sari ES, Kubaloglu A et al. Comparison of deep anterior lamellar keratoplasty and intrastromal corneal ring segment implantation in advanced keratoconus. J Cataract Refract Surg 2012; 38(2):324-32.
  12. Arriola-Villalobos P, Diaz-Valle D, Guell JL et al. Intrastromal corneal ring segment implantation for high astigmatism after penetrating keratoplasty. J Cataract Refract Surg 2009; 35(11):1878-84.
  13. Pinero DP, Alio JL, Morbelli H et al. Refractive and corneal aberrometric changes after intracorneal ring implantation in corneas with pellucid marginal degeneration. Ophthalmology 2009; 116(9):1656-64.
  14. Kubaloglu A, Sari ES, Cinar Y et al. A single 210-degree arc length intrastromal corneal ring implantation for the management of pellucid marginal corneal degeneration. Am J Ophthalmol 2010; 150(2):185-92 e1.
  15. Ferrer C, Alio JL, Montanes AU et al. Causes of intrastromal corneal ring segment explantation: clinicopathologic correlation analysis. J Cataract Refract Surg 2010; 36(6):970-7.
  16. Kanellopoulos AJ, Pe LH, Perry HD et al. Modified intracorneal ring segment implantations (INTACS) for the management of moderate to advanced keratoconus: efficacy and complications. Cornea 2006; 25(1):29-33.
  17. 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.
  18. National Institute for Health and Clinical Excellence (NICE). Guidance on corneal implants for keratoconus. 2007. Available online at: Last accessed August 2013.   




CPT  0099T  Implantation of intrastromal corneal ring segments 
ICD-9 Diagnosis  367.1  Myopia 
  371.60 – 371.62  Keratoconus code range 
ICD-10-CM (effective 10/1/14)  H18.601-H18.629 Keratoconus code range  
ICD-10-PCS (effective 10/1/14)   ICD-10-PCS codes are only used for inpatient services.  
    08U80JZ, 08U83JZ, 08U8XJZ, 08U90JZ, 08U93JZ, 08U9XJZ Surgical, eye, supplement, cornea, synthetic substitute, codes for right and left corneas and open, percutaneous and external approaches 



Policy History

Date Action Reason
04/1/05 Add policy to Other section, Vision subsection New policy
03/7/06 Replace policy Policy updated with literature review; no change in policy statement
12/12/06 Replace policy Policy updated with literature review; no change in policy statement. Reference numbers 6-11 added
01/10/08 Replace Policy Policy updated with literature review; references 12–14 added; no change in policy statement.
09/10/09 Replace policy Policy updated with literature review through August 2009; reference 15 added. Clinical input reviewed; policy statement revised; may be medically necessary in specified conditions.
09/16/10 Replace policy Policy updated with literature review through July 2010; references added; policy statements unchanged
09/01/11 Replace policy Policy updated with literature review through July 2011; reference 17 added; policy statements unchanged
9/13/12 Replace policy Policy updated with literature review through July 2012; Rationale section revised; references 6 and 8 added; some references removed; policy statements unchanged
9/12/13 Replace policy Policy updated with literature review through August 13, 2013; reference 9 added; policy statements unchanged