BlueCross and BlueShield of Montana Medical Policy/Codes
Refractive and Therapeutic Keratoplasty
Chapter: Surgery: Procedures
Current Effective Date: July 18, 2013
Original Effective Date: November 07, 2008
Publish Date: April 18, 2013
Revised Dates: February 8, 2012; April 17, 2013
Description

Refractive Procedures

Refractive keratoplasty is a generic term which includes surgical procedures performed to reshape the cornea of the eye to correct vision problems.  Vision occurs when light rays are bent or refracted by the cornea and lens and received by the retina, (the nerve layer at the back of the eye), in the form of an image, which is sent through the optic nerve to the brain.  Refractive errors occur when the eye cannot properly focus light and images appear out of focus.  The main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness) and astigmatism (distortion).  Presbyopia (aging eye) is a problem of the lens and is characterized by the inability to bring close objects into focus.  Refractive errors are generally corrected with glasses or contact lenses.  Refractive eye surgery (or refractive keratoplasty) involves procedures that permanently change the shape of the corneal surface.

Refractive keratoplasties include but are not limited to 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.
  • 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.
  • Photorefractive Keratectomy (PRK) uses a computerized laser to correct mild to moderate myopia.  The laser delivers bursts of ultraviolet light that vaporize precisely targeted corneal tissue, thus altering the corneal curvature, and improving the focus of light on the retina in the back of the eye.
  • Photoastigmatic Keratectomy (PARK or PRK-A) is a refractive surgical procedure to correct myopia with mild to moderate degrees of astigmatism. 
  • Conductive Keratoplasty involves the application of radiofrequency thermal energy to increase the curvature of the cornea and reduce hyperopia.
  • Astigmatic keratotomy (AK) (arcuate incision, corneal wedge resection) is a refractive surgical procedure similar to RK that is used to reduce astigmatism.  Instead of radial incisions, a curvilinear pattern is used to smooth the areas of the cornea that are too steeply curved.
  • Lamellar keratoplasty (LKP) partial thickness corneal grafting.
  • 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 three to four 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.
  • Laser In-Situ Keratomileusis (LASIK) is a procedure to correct or reduce moderate to high levels of myopia.  In LASIK, the surgeon creates a flap in the cornea using a microkeratome.  An excimer laser is used to remove a micro-thin layer of tissue from the exposed corneal surface.  The flap is replaced without the need for sutures.  This procedure is very similar to ALK for myopia.
  • 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).
  • Refractive Lensectomy is a refractive surgical procedure designed for use in patients 40 years of age and older whose natural lens has become more rigid and less flexible.  This procedure involves replacement of the natural lens of the eye with an accommodative intraocular lens using the same technique as modern cataract surgery.  This lens allows the restoration of the eye’s natural focusing ability.
  • Refractive Epikeratophakia is a surgical procedure which involves the removal of the corneal epithelium from the recipient eye and the suturing of a prelathed donor corneal graft onto the surface of the recipient cornea. 

Therapeutic Procedures

Therapeutic keratoplasties include but are not limited to the following surgical procedures:

  • Penetrating keratoplasty (PK) or keratoplasty (PKP) (corneal transplantation) is a therapeutic surgical procedure indicated for a number of serious corneal conditions, e.g., scarring, edema, thinning, and distortion.
    • Lamellar keratoplasty (LKP) is a partial thickness corneal grafting.
    • Penetrating keratoplasty (PK) is full thickness corneal grafting.

Lamellar or non-penetrating keratoplasty is a corneal transplant procedure in which a partial thickness of the cornea is removed.  The diseased tissue is replaced with a partial-thickness donor cornea.  Lamellar keratoplasty may be indicated for a number of corneal diseases, including scarring, edema, thinning, distortion, dystrophy, degenerations and keratoconus. 

Penetrating Keratoplasty (PK) involves the replacement of the full thickness of the cornea with donor cornea, while retaining the periphereal cornea.  Most penetrating keratoplasties are performed to improve poor visual acuity caused by an opaque cornea.  PK is also used to restore altered corneal structure; to prevent loss of the globe that has been punctured; and to remove active corneal disease, such as persistent severe bacterial, fungal, or amebic inflammation.

Epikeratophakia is a surgical procedure which involves the removal of the corneal epithelium from the recipient eye and the suturing of a prelathed donor corneal graft onto the surface of the recipient 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.

Endothelial keratoplasty (EK), also referred to as posterior lamellar keratoplasty (PLK), is a form of corneal transplantation in which the diseased inner layer of the cornea, the endothelium, is replaced with healthy donor tissue.  Specific techniques include Descemet’s stripping endothelial keratoplasty (DSEK); Descemet’s stripping automated endothelial keratoplasty (DSEAK), or Descemet’s membrane endothelial keratoplasty (DMEK) or Descemet’s membrane automated endothelial keratoplasty (DMAEK).

Descemet stripping with endothelial keratoplasty (DSEK) involves the scraping of the Descemet membrane and endothelium from the recipient cornea instead of the lamellar dissection and excision procedures performed in DLKP and DLEK.  DSEK is also less technically challenging than DLEK.  The primary complications of endothelial replacement procedures are disc dislocation and endothelial cell loss.

Deep anterior lamellar keratoplasty (DALK) is used when the pathology is confined to front layers of the cornea.  In this procedure, most of the anterior layers of the cornea (i.e., epithelium, Bowman membrane, and stroma) are removed. 

Deep lamellar keratoplasty (DLKP) is a surgical method that completely removes pathological corneal stromal tissue down to the Descemet membrane, followed by transplantation of donor tissue.  This technique was modified with redesigned instrumentation, and renamed deep lamellar endothelial keratoplasty (DLEK).

Descemet’s stripping endothelial keratoplasty (DSLEK) is a variation of the DLEK.  In this procedure the surgeon removes the endothelium and some (or all) of the Descemet’s membrane and transplants the endothelium, Descemet’s membrane, and a thin layer or stroma.

Keratoprosthetic devices are designed to be implanted in patients with severe bilateral corneal conditions, such as Stevens-Johnson syndrome, chemical burns, and repeated failure of PK.  In general, keratoprostheses consist of a transparent cylinder-shaped optical portion and a haptical portion.  The optical cylinder is inserted into a central circular opening of the opacified cornea, focusing images on a functioning retina.  The haptical section is fixed to and buried under neighboring tissue.  The different designs of keratoprostheses vary primarily in the haptical portion of the devices.  For example, the osteo-odonto-keratoprosthesis (OOKP) is a method of corneal substitution which uses a prosthesis composed of an acrylic optical cylinder mounted in a section of one of the patient’s own teeth.  This type of implant is proposed for use in patients who are at high risk of graft rejection, as autologous tissue is utilized for the procedure.  The biocolonisable microporous fluorocarbon haptic keratoprosthesis (BIOKOP) procedure utilizes a synthetic hydrogel core surrounded by a porous skirt that allows biointegration and prevents epithelial down growth.

The established surgical treatment for corneal disease is penetrating keratoplasty (PK), which involves the creation of a large central opening through the cornea and then filling the opening with full-thickness donor cornea that is sutured in place.  Visual recovery after PK may take one year or more due to slow wound healing of the avascular full-thickness incision, and the procedure frequently results in irregular astigmatism due to the sutures and the full-thickness vertical corneal wound.  PK is associated with an increased risk of wound dehiscence, endophthalmitis, and total visual loss after relatively minor trauma for years after the index procedure.  There is also risk of severe, sight-threatening complications such as expulsive suprachoroidal hemorrhage, in which the ocular contents are expelled during the operative procedure, as well as postoperative catastrophic wound failure.

A number of related techniques have been, or are being, developed to selectively replace the diseased endothelial layer.  One of the first endothelial keratoplasty (EK) techniques was termed deep lamellar endothelial keratoplasty (DLEK), which used a smaller incision than PK, allowed more rapid visual rehabilitation, and reduced postoperative irregular astigmatism and suture complications.  Modified EK techniques include endothelial lamellar keratoplasty, endokeratoplasty, posterior corneal grafting, and microkeratome-assisted posterior keratoplasty.  Most frequently used at this time are Descemet’s stripping endothelial keratoplasty (DSEK), which uses hand-dissected donor tissue, and Descemet’s stripping automated endothelial keratoplasty (DSAEK), which uses an automated microkeratome to assist in donor tissue dissection.  A laser may also be utilized for stripping in a procedure called femtosecond laser-assisted corneal endothelial keratoplasty (FLEK).  These techniques include some donor stroma along with the endothelium and Descemet’s membrane, which results in a thickened stromal layer after transplantation.  If the donor tissue comprises Descemet’s membrane and endothelium alone, the technique is known as Descemet’s membrane endothelial keratoplasty (DMEK).  By eliminating the stroma on the donor tissue and possibly reducing stromal interface haze, DMEK is considered a potential improvement over DSEK/DSAEK.  A variation of DMEK is Descemet’s membrane automated EK (DMAEK).  DMAEK contains a stromal rim of tissue at the periphery of the DMEK graft to improve adherence and increase ease of handling of the donor tissue.

EK involves removal of the diseased host endothelium and Descemet’s membrane with special instruments through a small peripheral incision.  A donor tissue button is prepared from corneoscleral tissue after removing the anterior donor corneal stroma by hand (e.g., DSEK) or with the assistance of an automated microkeratome (e.g., DSAEK) or laser (FLEK).  Several microkeratomes have received clearance for marketing through the U.S. Food and Drug Administration (FDA) 510(k) process.  Donor tissue preparation may be performed by the surgeon in the operating room or by the eye bank and then transported to the operating room for final punch out of the donor tissue button.  To minimize endothelial damage, the donor tissue must be carefully positioned in the anterior chamber.  An air bubble is frequently used to center the donor tissue and facilitate adhesion between the stromal side of the donor lenticule and the host posterior corneal stroma.  Repositioning of the donor tissue with application of another air bubble may be required in the first week if the donor tissue dislocates.  The small corneal incision is closed with one or more sutures, and steroids or immunosuppressants may be provided either topically or orally to reduce the potential for graft rejection.  Visual recovery following EK is typically achieved in 4-8 weeks, in comparison with the year or more that may be needed following PK.

Eye Bank Association of America (EBAA) statistics show the number of EK cases in the United States increased from 1,398 in 2005 to 14,159 in 2007.  Approximately one third of corneal transplants performed in the United States were EK procedures, and EK was performed for more than 85% of patients with endothelial disease.  As with any new surgical technique, questions have been posed about long-term efficacy and the risk of complications.  EK-specific complications include graft dislocations, endothelial cell loss, and rate of failed grafts.  Long-term complications include increased intraocular pressure, graft rejection, and late endothelial failure.  Also of interest is the impact of the surgeon’s learning curve on the risk of complications.

Policy

Each benefit plan or contract defines which services are covered, which are excluded, and which are subject to dollar caps or other limits.  Members and their providers have the responsibility for consulting the member's benefit plan or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply.   If there is a discrepancy between a Medical Policy and a member's benefit plan or contract, the benefit plan or contract will govern.

Refractive Procedures

BCBSMT considers procedures on the eye that are primarily refractive (changing the direction of light rays to correct vision) in nature or that are primarily to compensate for the native refractive error (farsightedness/nearsightedness) of the eye not medically necessary, including but not limited to:

  • Radial keratotomy (RK), minimally invasive radial keratotomy (mini-RK) and photorefractive keratectomy (PRK);
  • Photorefractive keratotomy (PRK) as a treatment of children with anisometropic amblyopia;
  • Astigmatic keratotomy (AK), whether performed independently or as a part of another service;
    • Photoastigmatic keratectomy (PARK or PAK-A);
    • Conductive keratoplasty (thermokeratoplasty);
    • Refractive lamellar keratoplasty when performed solely to correct astigmatism;
    • Automated lamellar keratoplasty (ALK);
    • Laser-In-Situ keratomileusis (LASIK);
    • Keratomileusis;
    • Refractive lensectomy or removal of the native lens when primarily to alter the refractive state of the eye;
    • Epikeratoplasty (epikeratophakia), when used primarily to compensate for native refractive errors.

Therapeutic Procedures

BCBSMT may consider penetrating keratoplasty (PK) for significant visual impairment medically necessary for any of the following indications:

  • Bullous keratoplasty; or
  • Chemical burns to the eye; or
  • Fuch’s dystrophy; or
  • Keratoconus; or
  • Severe corneal ulcers caused by bacterial, fungal, parasitic or viral eye infections; or
  • Severe traumatic injuries that pierce or cut the cornea; or
  • Severe corneal edema or scarring;
  • Descemetocele (corneal thinning).

Endothelial keratoplasty (EK), Descemet’s stripping endothelial keratoplasty (DSEK),  or Descemet’s membrane endothelial keratoplasty (DMEK) and Descemet’s stripping automated endothelial keratoplasty (DSAEK) or Descemet’s membrane automated endothelial keratoplasty (DMAEK) may be considered medically necessary for the treatment of endothelial dysfunction, including but not limited to:

  • Fuchs’ endothelial dystrophy,
  • Aphakic, and
  • Pseudophakic bullous keratopathy, and
  • Failure or rejection of a previous corneal transplant.

NOTE:  Endothelial keratoplasty should not be used in place of PK for conditions with concurrent endothelial disease and anterior corneal disease.  These situations would include concurrent anterior corneal dystrophies, anterior corneal scars from trauma or prior infection, and ectasia after previous laser vision correction surgery.  EK should be performed by surgeons who are adequately trained and experienced in the specific techniques and devices used.

Lamellar or non-penetrating keratoplasty may be considered medically necessary for patients with corneal scarring, edema, thinning, distortion, dystrophy, degenerations and keratoconus. 

Epikeratoplasty (or epikeratophakia or lamellar keratoplasty or non-penetrating keratoplasty) may be considered medically necessary in the treatment of childhood aphakia.

The following therapeutic keratoplasty procedures are considered experimental, investigational and unproven:

  • Deep anterior lamellar keratoplasty (DALK); and
  • Deep lamellar keratoplasty (DLKP); and
  • Deep lamellar endothelial keratoplasty (DLEK); and
  • Keratoprosthesis; and
  • Keratophakia

Rationale

Refractive Procedures

Refractive Keratoplasty

Myopia, hyperopia and astigmatism are extremely common refractive errors of the eye and may be considered anatomic variants.  For example, it is estimated that 43% of Americans report low myopia, 3.2% had high myopia and 0.2% had extreme myopia.  These common refractive errors are effectively corrected with either spectacles or contact lenses.  Refractive surgery offers a permanent form of correction.

A critical issue in assessment of refractive surgical procedures is the medical outcome.  Although the efficacy of refractive surgery is improving, the accuracy and precision of the refractive corrections achieved is substantially less than that which can be achieved with spectacle correction.  Spectacles or contact lenses have been shown to provide more accurate corrections of refractive errors than refractive surgery.

Myopia is the most common indication for refractive surgery and most reports of refractive surgery have focused on myopic eyes.  At this point the Laser-In-Situ keratomileusis (LASIK) procedure is emerging as an increasingly popular approach.  In a large series of 1062 eyes in 574 myopic patients, Stutling et al. reported that complications occurred in 5% of patients.  Complications included corneal flap complications, epithelial in-growth or keratitis.  There was a reduction in best-corrected visual acuity in 50 patients.  Among 148 eyes with preoperative myopia greater than 10D (i.e., severe myopia), 8.8% lost more than two Snellen lines of visual acuity.  Additionally, 26% of eyes in this group underwent repeat LASIK procedures.  Perez-Santonja et al. reported a case series of 143 eyes with high myopia.  Preoperatively the mean best-corrected visual acuity (BCVA) was 0.51, while the postoperative BCVA was 0.59, a difference that did not reach statistical significance.  The mean postoperative uncorrected visual acuity was 0.47, less than the preoperative BCVA.  Results with photorefractive keratectomy for high myopia may be worse; case series have reported losses of BCVA in from 0 to 33% of cases.  Hersh et al. reported on the results of a study that randomized 220 patients with moderate to high myopia to undergo either PRK or LASIK.  At all-time point studies, relatively more patients in the PRK group lost two Snellen lines or more compared to the LASIK group.  The differences in the pre- and postoperative BCVA were not reported for those with high myopia.

In 1996, the American Academy of Ophthalmology (AAO) issued a preliminary procedure assessment of keratomileusis in situ.  This assessment concluded, "A large number of alternative procedures for surgical correction of high myopia and hyperopia have been proposed and are under investigation, including clear lens extraction, phakic intraocular lenses, excimer laser photorefractive keratectomy, laser in situ keratomileusis, and automated lamellar keratoplasty.”  The peer reviewed literature contains a lack of information on the relative safety and efficacy of these competing approaches.

In 1996, the AAO also published an assessment of epikeratoplasty.  This assessment stated, “epikeratoplasty is an increasingly unpopular option for correcting myopia because of its lack of predictability and poor optical results as measured by contrast sensitivity tests.”  The assessment further concluded that “…myopic epikeratoplasty has a very limited place in the correction of myopia given the advances in excimer laser technology and radial keratotomy.”

In 1994, the 10-year follow up of the study Prospective Evaluation of Radial Keratotomy (PERK) was published.  The PERK study was a multi-institutional study designed to assess the long-term effects of radial keratotomy on mild to moderate myopia in 793 eyes (427 patients).  Uncorrected visual acuity was 20/20 or better in 53% of 681 eyes and 20/40 or better in 85%.  Among 310 patients with bilateral radial keratotomy, 70% reported not wearing spectacles or contact lenses for distance vision at two years.  The major finding associated with long term follow up was the instability of the refractive error; 43% of eyes changed refractive power in the hyperopic direction, termed hyperopic shift.

Refractive lensectomy is a clear lens extraction technique similar to cataract extraction, where the eyes’ natural lens is removed and replaced with an accommodating intraocular lens.  The surgical procedure has been shown to be safe and efficacious.  However, studies of refractive surgical procedures have shown that eyeglasses or contact lenses provide more accurate corrections of refractive errors in non cataractous patients. 

Therapeutic Procedures

Therapeutic Keratoplasty

Corneal transplantation is the most common type of transplant done in the United States.  Penetrating keratoplasty (PK) is considered a standard surgical intervention for corneal conditions such as keratoconus, bullous keratopathy, Fuchs' endothelial dystrophy, corneal thinning, and graft failure.  Surgical treatment of corneal disorders is evolving with attempts to replace only the diseased portion of the cornea.  Various techniques of lamellar keratoplasty have emerged, which have advantages over PK, such as less suturing and faster visual rehabilitation.  These techniques include deep anterior lamellar keratoplasty (DALK), deep lamellar keratoplasty (DLKP), deep lamellar endothelial keratoplasty (DLEK), and Descemet stripping with endothelial keratoplasty (DSEK).

The available studies evaluating the safety and efficacy of DALK and DLKP are nonrandomized and generally of small sample sizes, making it difficult to generalize results to the larger population.  Although promising, DALK and DLKP are considered investigational at this time.  DLEK and DSEK, performed to replace the endothelium or posterior portion of the cornea, have been proposed for the treatment of endothelial dysfunction.  Of these two techniques, DLEK is considered to be more technically challenging.  DSEK is rapidly becoming the procedure of choice and is increasingly being seen as the standard of care for patients with visual impairment from corneal endothelial disease.

There is insufficient evidence in the peer-reviewed medical literature regarding patient selection criteria, safety and efficacy of keratoprosthesis.

2012 Update

Descemet’s Stripping Endothelial Keratoplasty and Descemet’s Stripping Automated Endothelial Keratoplasty (DSEK/DSAEK)

A review of the safety and efficacy of DSAEK, performed by the American Academy of Ophthalmology’s (AAO) Ophthalmic Technology Assessment Committee, identified one level-I study (randomized controlled trial [RCT] of precut vs. surgeon dissected) along with nine level-II (well-designed observational studies) and 21 level-III studies (mostly retrospective case series).  Although more than 2,000 eyes treated with DSAEK were reported on in different publications, most were reported by one research group with some overlap in patients.  The main results from this evidence review are as follows:

  • DSAEK-induced hyperopia ranged from 0.9 to 1.5 diopters (D), with minimal induction of astigmatism (ranging from 0 to 0.6 D).
  • The reporting of visual acuity was not standardized in the studies reviewed.  The average best-corrected visual acuity (BCVA) ranged from 20/33 to 20/66, and the percentage of patients seeing 20/40 or better ranged from 38% to 100%.
  • The most common complication from DSAEK in the studies reviewed was posterior graft dislocation (mean 14%; range 0–82%), with a lack of adherence of the donor posterior lenticule to the recipient stroma, typically occurring within the first week.  It was noted that this figure may be skewed by multiple publications from one research group with low complication rates.  Graft dislocation required additional surgical procedures (rebubble procedures) but did not lead to sight-threatening vision loss in the articles reviewed.
  • Endothelial graft rejection occurred in an average 10% of patients (range, 0–45%); most were reversed with topical or oral immunosuppression, with some cases progressing to graft failure.  Primary graft failure, defined as unhealthy tissue that has not cleared within two months, occurred in 5% of patients (range 0–29%).  Iatrogenic glaucoma occurred in an average of 3% of patients (range 0–15%) due to a pupil block induced from the air bubble in the immediate postoperative period or delayed glaucoma from topical corticosteroid adverse effects.
  • Endothelial cell loss, which provides an estimate of long-term graft survival, was an average 37% at six months and 42% at 12 months.  This percentage of cell loss was reported to be similar to that observed with penetrating keratoplasty (PK).

The AAO technology assessment concluded that DSAEK appears at least equivalent to PK in terms of safety, efficacy, surgical risks, and complication rates, although long-term results are not yet available.  The evidence also indicated that endothelial keratoplasty (EK) is superior to PK in terms of refractive stability, postoperative refractive outcomes, wound- and suture-related complications, and risk of intraoperative choroidal hemorrhage.  The reduction in serious and occasionally catastrophic adverse events associated with PK has led to the rapid adoption of EK in place of PK for the treatment of corneal endothelial failure.

It was noted that the specific techniques are still evolving; the (AAO) Ophthalmic Technology Assessment Committee, identified the following future research needs:

“Future research should be directed at assessing better surgical techniques for increasing endothelial cell survival with endothelial procedures, whether this represents new surgical techniques and/or new instrumentation….  Both new surgical techniques such as Descemet’s membrane endothelial keratoplasty and new insertion techniques must be validated by basic laboratory ex vivo studies and large, well-designed cohort or randomized controlled studies and/or long-term prospective studies demonstrating complication rates and long-term endothelial cell survival.”

A number of studies included in the AAO review were from Chen and colleagues at the Devers Eye Institute.  One of the publications reported six-month clinical outcomes from 100 of the first 150 consecutive eyes treated by DSAEK at this tertiary care center during 2005 and 2006.  Fifty eyes were not available for six-month follow-up due to illness, death, or residence out of state.  Preoperatively, every patient had a diagnosis of endothelial dysfunction with clinically evident stromal edema; BCVA averaged 20/86, and uncorrected visual acuity (UCVA) averaged 20/155.  Cataract surgery (n=51) was concurrently performed if the patient had visually significant cataract or mild cataract with expectation of progression and minimal remaining accommodative amplitude.  At six-month follow-up all grafts were clear, and there were no primary graft failures.  There was an average gain of greater than four Snellen lines with an average BCVA of 20/38.  Eighty-five percent of eyes had better visual acuity than they had preoperatively, and 81% obtained vision of 20/40 or better.  When patients were excluded due to other possible causes of visual loss such as macular or glaucomatous damage, BCVA improved from 20/60 to 20/30 (n=74), with an average gain of three Snellen lines.  Eighty-eight percent of eyes in this group had better visual acuity at six months than they had preoperatively, and 97% of eyes had obtained a vision of 20/40 or better.  The reporting of results on visual acuity did not distinguish between patients who had received concurrent cataract surgery and those whose improvements could be attributed entirely to DSAEK.

A search of the MEDLINE database, performed to identify additional reports published after the 2009 AAO technology assessment, identified several case reports on complications (e.g., epithelial ingrowth and adverse effects of the bubbles), as well as a number of papers on DSEK/DSAEK technique.  Chen and colleagues reported the effect of training on outcomes following DSAEK.  Of 327 consecutive cases performed at their tertiary care centers during 2005–2007, 235 were performed by the attending corneal surgeon, and 92 were performed by the corneal fellows.  Loss to follow-up at six months (36% to 37%) was due to illness, death, or residence out of state.  For the 208 patients who returned for the six-month assessment, 91% of those treated by the attending surgeon and 69% of those treated by fellows had also undergone concurrent phacoemulsification for visually significant cataract at the time of DSAEK.  There were no graft failures in either group, and all grafts were clear at the six-month assessment.  Dislocations and endothelial cell loss were similar in the two groups of patients (2% vs.1% dislocations, respectively, and mean cell loss of 32% and 35%, respectively).  Patients from both groups gained approximately four Snellen lines, with a six-month average best corrected visual acuity of 20/37 and 20/36.  Vision of 20/40 or better was obtained by 78% of patients treated by attending surgeons and 90% of patients treated by fellows.  Vision of 20/20 or better was obtained by 14% of patients treated by attending surgeons and 3% treated by fellows.

Femtosecond Laser-Assisted Corneal Endothelial Keratoplasty (FLEK)

Cheng et al. reported a multicenter randomized trial from Europe that compared FLEK with PK.  Eighty patients with Fuchs’ endothelial dystrophy, pseudophakic bullous keratopathy, or posterior polymorphous dystrophy, and best spectacle-corrected visual acuity lower than 20/50, were included in the study.  In the FLEK group, four of the 40 eyes did not receive the treatment due to significant preoperative events and were excluded from the analysis.  Eight eyes failed (22% of 36), and two patients were lost to follow-up due to death in the FLEK group.  Only one patient was lost to follow-up in the PK group due to health issues.  At 12 months postoperatively, refractive astigmatism was lower in the FLEK group than the PK group (86% vs. 51%, respectively, with astigmatism < 3.0 D), but there was greater hyperopic shift.  Mean best corrected visual acuity was better following PK than FLEK at 3-, 6-, and 12-month follow-up.  There was greater endothelial cell loss in the FLEK group (65%) than the PK group (23%).  With the exception of dislocation and need for repositioning of the FLEK grafts in 28% of eyes, the percentage of complications were similar in the two groups.  Complications in the FLEK group were due to pupillary block, graft failure, epithelial ingrowth, and elevated intraocular pressure, whereas complications in the PK group were related to the sutures and elevated intraocular pressure.

Descemet’s Membrane Endothelial Keratoplasty (DMEK) and Descemet’s Membrane Automated Endothelial Keratoplasty (DMAEK)

Recent reviews suggest that by eliminating the stroma on the donor tissue, DMEK/DMAEK may reduce stromal interface haze and provide better visual acuity outcomes than DSEK/DSAEK.  Current literature is limited, although a review of the first 50 consecutive cases from a group in Europe suggests that a greater number of patients achieve 20/25 vision or better with DMEK.  Of the 50 consecutive eyes, 10 (20%) required a secondary DSEK for failed DMEK.  For the remaining 40 eyes, 95% had a best-corrected visual acuity of 20/40 or better, and 75% had a best-corrected visual acuity of 20/25 or better.  Donor detachments and primary graft failure with DMEK were problematic, and the ultimate success of DMEK will depend on the reliability of graft adherence and demonstrated improvement in visual acuity outcomes in comparison with DSAEK.

Price and colleagues reported three-month outcomes from a prospective consecutive series of 60 cases of DMEK.  Indications for DMEK were Fuchs’ dystrophy, pseudophakic bullous keratopathy, failed PK, or failed EK.  Twelve DMEK procedures were combined with other procedures to treat coexisting conditions, and 48 cases were stand-alone graft procedures.  Preoperative BCVA ranged from 20/25 to only hand movements.  Excluding four eyes (7%) that had significant ocular comorbidity at baseline, BCVA at three months ranged from 20/20 to 20/50, with a mean and median of 20/25.  Sixty-three percent of patients had BCVA of 20/25 or better, while 94% of eyes had a BCVA of 20/40 or better.  There was a significant hyperopic shift and a mean cell loss at three months of 30%.  Although visual acuity outcomes appeared to be improved over a DSAEK series from the same investigators, preparation of the donor tissue and attachment of the endothelial graft were found to be more challenging.

McCauley et al. reported a prospective consecutive series of their initial 40 cases (36 patients) of DMAEK (microkeratome dissection and a stromal ring) in 2011.  Indications for EK were Fuchs’ endothelial dystrophy (87.5%), pseudophakic bullous keratopathy (7.5%), and failed EK (5%).  Patients with coexisting retinal pathology (e.g., six with macular degeneration and one with macular hole) were included in the study but excluded from pre- and postoperative vision analysis.  Air was reinjected in 10 eyes (25%) to promote graft attachment; two grafts (5%) failed to clear and were successfully regrafted.  Compared with a median BCVA 20/40 at baseline (range, 20/25-20/400), median BCVA at one month was 20/30 (range, 20/15 -20/50).  At six months, 48% of eyes had equal to or greater than 20/20 vision, 74% were equal to or greater than 20/25, 93% were equal to or greater than 20/30 and 100% were equal to or greater than 20/40.  Mean endothelial cell loss at six months relative to baseline donor cell density was 31%.  Central corneal thickness, assessed by ultrasonic pachymetry, was 632 microns at baseline and 525 microns at six months.

Long-term graft survival with these new techniques is presently unknown.  However, current procedures result in acceptable short-term survival, and additional surgical intervention can be performed with a low risk of visual loss.  Due to the marked reduction in serious complications compared to the alternative, DSEK/DSAEK has become the preferred approach for endothelial dysfunction among corneal surgeons.  Therefore, these techniques may be considered medically necessary.

EK will continue to evolve as techniques are modified in an attempt to improve donor tissue adherence and increase endothelial survival.  Randomized controlled studies and/or long-term prospective studies will be needed to adequately evaluate these new procedures.

The Health Policy Committee of the American Academy of Ophthalmology (AAO) published a position paper on endothelial keratoplasty, stating that the optical advantages, speed of visual rehabilitation, and lower risk of catastrophic wound failure have driven the adoption of EK as the standard of care for patients with endothelial failure and otherwise healthy corneas. 

The AAO position paper was based in large part on a comprehensive review of the literature on Descemet’s stripping automated endothelial keratoplasty (DSAEK) by the American Academy of Ophthalmology’s Ophthalmic Technology Assessment Committee.  The Technology Assessment Committee concluded that “the evidence reviewed suggests DSAEK appears safe and efficacious for the treatment of endothelial diseases of the cornea.  Evidence from retrospective and prospective DSAEK reports described a variety of complications from the procedure, but these complications do not appear to be permanently sight threatening or detrimental to the ultimate vision recovery in the majority of cases.  Long-term data on endothelial cell survival and the risk of late endothelial rejection cannot be determined with this review.”  “DSAEK should not be used in lieu of PK for conditions with concurrent endothelial disease and anterior corneal disease.  These situations would include concurrent anterior corneal dystrophies, anterior corneal scars from trauma or prior infection, and ectasia after previous laser vision correction surgery.”

The United Kingdom’s National Institute for Health and Clinical Excellence (NICE) released guidance on corneal endothelial transplantation in 2009.  The studies reviewed used DLEK, DSEK, and DSAEK.  Additional data reviewed from the United Kingdom Transplant Register showed lower graft survival rates after EK than after PK; however, the difference in graft survival between the two procedures was noted to be narrowing with increased experience in EK use.  The guidance concluded that “current evidence on the safety and efficacy of corneal endothelial transplantation (also known as endothelial keratoplasty [EK]) is adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance and consent.”  The Committee noted that techniques for this procedure continue to evolve, and thorough data collection should continue to allow future review of outcomes.

Summary

Endothelial keratoplasty, and particularly DSEK, DSAEK, DMEK and DMAEK, are relatively new procedures.  FLEK has been reported as another way to prepare the donor endothelium.  The literature and clinical input available at this time indicates that endothelial keratoplasty reduces the serious complications associated with penetrating keratoplasty.  Specifically, visual recovery occurs much earlier, and because EK maintains an intact globe without a sutured donor cornea, astigmatism and the risk of severe, sight-threatening complications such as expulsive suprachoroidal hemorrhage and postoperative catastrophic wound failure are eliminated.  These improvements appear to have resulted in rapid acceptance of these procedure with a trend toward intervention at an earlier stage of endothelial disease.

Coding

Disclaimer for coding information on Medical Policies         

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy.  They may not be all-inclusive.           

The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers.  Only the written coverage position in a medical policy should be used for such determinations.           

Benefit coverage determinations based on written Medical Policy coverage positions must include review of the member’s benefit contract or Summary Plan Description (SPD) for defined coverage vs. non-coverage, benefit exclusions, and benefit limitations such as dollar or duration caps. 

ICD-9 Codes

11.71, 076.1, 190.3, 198.4, 224.3, 234.0, 238.8, 239.89, 239.89, 264.6, 367.0, 367.1, 367.20, 367.21, 367.22, 367.31, 367.32, 367.89, 367.9, 370.00- 370.07, 370.40, 370.49, 370.62, 370.63, 370.8, 371.01-371.04, 371.11-371.13, 371.16, 371.20, 371.23, 371.30-371.33, 371.40, 371.41, 371.46, 371.53, 371.57, 371.60-371.62, 372.50-372.54, 372.63, 379.31, 694.61, 695.13, 743.35, 743.41, 743.42, 871.0, 871.1, 871.2, 871.5, 871.6, 871.9, 906.5, 940.2-940.4, 940.9, 941.12, 941.22, 941.32, 996.51, 996.53, 996.63, 996.75, 997.99, 998.32, 998.83, V42.5, V43.1, V45.69

ICD-10 Codes
A71.1, B60.13 - H16.8, H16.001-H16.009, H16.011 - H16.019, H16.021 - H16.029, H16.031 - H16.039, H16.041 - H16.049,  H16.061 - H16.069, H16.071 - H16.079, H16.441 - H16.449, H16.051 - H16.059, H16.071,  H16.079, , H16.201 - H16.209,  H16.291 - H16.299, H16.421 - H16.429, H17.10 - H17.13    H17.811 - H17.819, H17.821 - H17.829,    H18.10 - H18.13,        H18.20, H18.021 - H18.029, H18.30, H18.40, H18.051 - H18.059   H18.061-H18.069, H18.411 - H18.419, H52.00 - H52.03,  H52.6, H52.10 - H52.13, H52.31, H52.32, H52.201 - H52.209,  H52.211 - H52.219,  H52.221 - H52.229, H18.311 - H18.319,  H18.321 - H18.329, H18.331 - H18.339
Procedural Codes: 0289T, 0290T, 65710, 65730, 65750, 65755, 65756, 65757, 65760, 65765, 65767, 65770, 65771, 65772, 65778, 65779, S0800, S0810, V2785
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History
February 2012 Policy updated, changed not medically necessary statement to investigational.
April 2013 Policy title changed from "Refractive Keratoplasty" to "Refractive and Therapeutic Keratoplasty".  Language and formatting revised.  Radial keratotomy changed from possibly medically necessary to not medically necessary.  Additional criteria added that are medically necessary.
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Refractive and Therapeutic Keratoplasty