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Chandelier illumination to complete Descemet stripping through severe hazy cornea during Descemet-stripping automated endothelial keratoplasty

Inoue, Tomoyuki MD; Oshima, Yusuke MD; Shima, Chiharu MD; Hori, Yuichi MD; Maeda, Naoyuki MD; Tano, Yasuo MD

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Journal of Cataract & Refractive Surgery: June 2008 - Volume 34 - Issue 6 - p 892-896
doi: 10.1016/j.jcrs.2008.02.032
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Abstract

Descemet stripping automated endothelial keratoplasty (DSAEK), which displaces the diseased host endothelium and Descemet membrane through a small incision without full-thickness corneal penetration, has been gaining attention as an alternative to conventional penetrating keratoplasty (PKP) to treat endothelial dysfunction such as Fuchs dystrophy and pseudophakic bullous keratopathy.1–5 The less invasive procedure offers several advantages over conventional PKP including better preservation of host corneal biomechanical properties and structural integrity, minimally induced changes in corneal curvature, and fewer ocular surface complications, thus resulting in rapid visual recovery.1–5 However, this promising new procedure for treating advanced endothelial diseases is considered challenging because of difficulties in intraocular visualization and manipulation in patients with very hazy corneas.2,6

To overcome these challenges and expand the surgical indications for DSAEK to advanced stages of endothelial dysfunction, we refined the intraocular illumination technique to facilitate clear intraocular visibility and the safety of Descemet stripping and sequential manipulation through a hazy cornea. In this article, we demonstrate the efficacy of chandelier illumination-assisted DSAEK for the treatment of severe bullous keratopathy. We present 2 illumination approaches using chandelier illumination for complete Descemet stripping with or without cataract surgery.

SURGICAL TECHNIQUE

A commercially available, self-retaining 25-gauge (0.5 mm) or 27-gauge (0.35 mm) chandelier illumination fiber (Synergetics, Inc.) with a mercury vapor light source (Photon II, Synergetics, Inc.) was used.7,8 The chandelier illumination technique was performed only in cases with severe corneal haze through which intraocular visibility could not be obtained with conventional microscopic illumination (Figure 1, A) or with an illumination light pipe (Figure 1, B). The technique was not used in any case of longstanding bullous keratopathy with dense stromal scarring because PKP is currently a more suitable procedure.

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Figure 1:
Intraoperative photographs of chandelier illumination–assisted DSAEK in pseudophakia. A: Corneal haze reflects the light from a conventional surgical microscope and hinders visibility inside the eye. B: Light pipe spot lighting in the anterior chamber is insufficient to improve the intraocular visibility. C: A 25-gauge self-retaining chandelier fiber is set at the corneal limbus with the tip inside the anterior chamber through a small side-port incision. D: Sclerotic scattering-like illumination from the sclerocorneal margin and endoillumination from the anterior chamber, both generated by the chandelier illumination fiber, offer sufficient lighting to clearly view the anterior chamber and the corneal endothelial layer despite a hazy cornea. E: The stripped Descemet membrane and the tip of the reversed Sinskey hook are visualized clearly through the hazy cornea. F: Descemet membrane can be stripped as a single sheet and confirmed under chandelier illumination without biological staining.

For chandelier illumination-assisted DSAEK, 2 illuminating approaches can be used depending on whether DSAEK is performed with or without cataract surgery.

Anterior Chamber Illumination for DSAEK in Pseudophakia

In patients with pseudophakia, a self-retaining chandelier illumination fiber is inserted into the anterior chamber through a corneal side port inferonasally at the corneal limbus (Figure 1, C). The tip of the chandelier probe inserted approximately 2.0 to 3.0 mm into the anterior chamber provides optimal illumination to facilitate visibility of the corneal endothelial layer and the anterior chamber. In contrast to the poor visibility under conventional microscopic illumination and spotlight illumination using a light pipe, excellent intraocular visualization is obtained by a sclerotic scattering-like illumination from the sclerocorneal margin and endoillumination from the anterior chamber (Figure 1, D), both of which are generated by the chandelier illumination fiber. All manipulations and the instrument used in the anterior chamber for Descemet stripping and the stripped endothelial membrane itself are well visualized through the hazy cornea even without biological staining to enhance membrane visualization (Figure 1, D and E). Descemet membrane can be stripped successfully in 1 sheet, which eliminates concerns about residual membrane adhering to the recipient stroma (Figure 1, F). The detailed surgical procedures are available on the online video.

Because of the hands-free and self-retaining nature of the chandelier fiber, bimanual manipulation during DSAEK can be performed easily, similar to manipulations performed using conventional microscopic illumination. After the tip of the chandelier fiber is removed from the corneal side port, the corneal wound can be self-sealed or sealed easily with slight corneal stromal hydration at the end of surgery.

Retroillumination for DSAEK Combined with Cataract Surgery

Patients with Fuchs dystrophy or laser iridectomy–induced bullous keratopathy frequently have loss of vision from coexisting dense cataracts. In these patients, simultaneous DSAEK and phacoemulsification with intraocular lens (IOL) implantation, the so-called triple procedure, has been reported to be a beneficial treatment option, providing rapid visual rehabilitation with predictable refractive outcomes.9 However, a disadvantage of combined DSAEK and phacoemulsification is that cataract surgery must be performed through a cloudy cornea.9

Although the anterior chamber illumination technique is useful for visualizing the corneal endothelial layer for Descemet stripping through a hazy cornea, this approach should not be used when performing cataract surgery because the scattered reflection from the corneal haze interferes with intracapsular visibility, especially visibility of the posterior capsule.

In patients with severe corneal haze requiring the triple procedure, a chandelier fiber setting at the pars plana is useful for both cataract surgery and DSAEK (Figure 2, A). After retrobulbar anesthesia, a 25-gauge chandelier fiber is inserted transconjunctivally into the vitreous cavity through a sclerotomy introduced by a 25-gauge needle inserted 3.5 mm posterior to the corneal limbus. It is not necessary to perform conjunctival peritomy or vitrectomy before inserting the chandelier fiber. By inserting the tip of the chandelier fiber into the sclerotomy, the footplate keeps the chandelier in contact with the eye and prevents the fiber from advancing into the vitreous cavity and causing retinal complications. Retroillumination generated by the chandelier fiber and mercury vapor light source provides excellent intraocular visibility, as we have described.8 Retroillumination from the posterior side is sufficient to support safe intracapsular manipulation during phacoemulsification and IOL insertion and also sufficiently bright to provide clear visibility of the anterior chamber, thus supporting the safety of Descemet stripping (Figure 2, B) and subsequent DSAEK manipulations.

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Figure 2:
Intraoperative photographs of chandelier retroillumination–assisted DSAEK combined with cataract surgery. A: The self-retaining chandelier stays in the inferotemporal pars plana region by virtue of its design without the need for sutures. A footplate (arrow) keeps the chandelier in contact with the eye and prevents the chandelier fiber from advancing into the vitreous cavity. Phacoemulsification and IOL implantation have been performed under retroillumination.8 B: Chandelier retroillumination passing through the pupil (arrows) creates a large oval spot (arrowheads) on the retrocorneal surface. Retroillumination offers sufficient lighting to clearly view the anterior chamber without obstruction by the hazy cornea for Descemet stripping. C: Descemet membrane can be stripped in 1 sheet (arrowheads). D: At the end of surgery, the tip of the chandelier fiber is easily removed from the pars plana. The scleral wound self seals without suture placement.

Descemet membrane is well observed and can be stripped successfully in 1 sheet; the technique can be performed under the chandelier illumination via the corneal limbal approach (Figure 2, C). After the donor graft is inserted and air is injected into the anterior chamber to press the graft sheet against the recipient corneal stroma, centering and apposition of the donor graft sheet to the recipient is well visualized under retroillumination.

After the chandelier fiber is removed from the ciliary margin at the end of surgery, the scleral wound self-seals without sutures (Figure 2, D). If a minute amount of vitreous gel spills from the sclerotomy after the chandelier fiber is removed, it can be removed using a spring scissors followed by gentle repositioning of the conjunctiva over the sclerotomy.

In patients with advanced bullous keratopathy, corneal clarity can be restored successfully by anterior chamber chandelier illumination–assisted DSAEK (Figure 3) and chandelier retroillumination–assisted triple procedure.

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Figure 3:
A: Postoperative slitlamp photograph of the left eye shows restoration of corneal clarity after DSAEK under anterior chamber chandelier illumination. Despite subtle opacification in the corneal stroma, the visual acuity improved from 0.3 to 0.6 1 month postoperatively. B: Anterior segment optical coherence tomography image shows that the host cornea has recovered to within a normal range of thickness and the donor endothelial graft sheet is successfully attached to the recipient stroma without residual remnants of the original Descemet membrane.

DISCUSSION

Despite encouraging surgical outcomes after DSAEK for endothelial dysfunction, eyes with advanced bullous keratopathy present challenges for DSAEK because of the difficulty of visualizing Descemet membrane and the donor tissue behind a hazy, edematous recipient corrna.2,6 Several technical modifications, such as removal of the recipient epithelium2 and biological staining of the donor and/or recipient tissues with trypan blue (Vision Blue, DORC International BV),4,6,10 have been reported to improve intraocular visibility under conventional microscopy. However, microscopic illumination is limited for intraocular visualization through severe bullous keratopathy because diffuse illumination from the microscope is scattered by the corneal haze, thus interfering with intraocular visibility. The anterior chamber illumination technique using a light pipe has been reported to be helpful during cataract surgery in cases with mild or moderate corneal haze.11,12 However, spotlight illumination from a small light pipe is insufficient to clearly visualize the anterior and posterior chambers in eyes with severe bullous keratopathy. The need to hold the light pipe makes it difficult for the surgeon to perform bimanual manipulations such as Descemet stripping and donor graft insertion during DSAEK.

In contrast to the limitations of microscopic illumination and light pipe spot lighting, we found that chandelier illumination from the posterior side is sufficiently bright to perform cataract surgery through a very hazy cornea.8 By changing the position of the chandelier fiber, we showed that chandelier illumination can also provide excellent intraocular visibility during DSAEK in patients with advanced bullous keratopathy. Although it must be performed cautiously to prevent possible posterior segment complications, particularly when setting up the chandelier fiber for the pars plana approach, the chandelier illumination technique has several advantages: The design of the chandelier fiber allows easy entry without a conjunctival peritomy; the fiber is self-retaining (hands free) and the wound self seals after the fiber is removed; the technique provides excellent intraocular visibility through very hazy corneas; and there is no need for epithelial removal and biological staining for improved visualization. Finally, it is a retroillumination technique that is highly compatible with the triple procedure.

Descemet stripping might not be a critical procedure in every case, especially those with a normal Descemet membrane13 or those in the early stage of endothelial decompensation without fibrotic changes in Descemet membrane. However, in advanced bullous keratopathy, endothelial dysfunction as well as degenerative and fibrotic changes in Descemet membrane may contribute to the corneal haze. Inadequate Descemet membrane stripping that leaves fibrotic remnants adhering to the recipient stroma could result in poor donor graft adhesion.14 Therefore, stripping the diseased Descemet membrane in 1 sheet without remnants on the recipient stroma is important to prevent this complication in advanced bullous keratopathy.

We understand that DSAEK cannot replace PKP in every advanced case, especially cases with irreversible severe stromal opacification. Nevertheless, clear visibility under chandelier illumination makes it safe and easy to perform complete Descemet membrane stripping from the recipient through a very hazy cornea, thus enhancing favorable surgical outcomes in selected cases, as shown in Figure 3. Furthermore, because of the intraocular visibility obtained under chandelier illumination, neither epithelial removal nor biological staining was required to improve intraocular visualization in our recent series. Descemet stripping automated endothelial keratoplasty can be a less traumatic procedure even in patients with advanced bullous keratopathy.

To our knowledge, this is the first report to describe the use of chandelier illumination in DSAEK. Although caution must be taken when setting up the chandelier fiber, especially during the pars plana approach to prevent possible posterior segment complications, self-retaining chandelier illumination-assisted DSAEK may expand the surgical indications of DSAEK to include challenging cases.

REFERENCES

1. Price FW Jr, Price MO. Descemet's stripping with endothelial keratoplasty in 50 eyes: a refractive neutral corneal transplant. J Refract Surg. 2005;21:339-345.
2. Price FW Jr, Price MO. Descemet's stripping with endothelial keratoplasty in 200 eyes: early challenges and techniques to enhance donor adherence. J Cataract Refract Surg. 2006;32:411-418.
3. Gorovoy MS. Descemet-stripping automated endothelial keratoplasty. Cornea. 2006;25:886-889.
4. Mearza AA, Qureshi MA, Rostron CK. Experience and 12-month results of Descemet-stripping endothelial keratoplasty (DSEK) with a small-incision technique. Cornea. 2007;26:279-283.
5. Koenig SB, Covert DJ. Early results of small-incision Descemet's stripping and automated endothelial keratoplasty. Ophthalmology. 2007;114:221-226.
6. Price MO, Price FW Jr, Trespalacios R. Endothelial keratoplasty technique for aniridic aphakic eyes. J Cataract Refract Surg. 2007;33:376-379.
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11. Farjo AA, Meyer RF, Farjo QA. Phacoemulsification in eyes with corneal opacification. J Cataract Refract Surg. 2003;29:242-245.
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APPENDIX SUPPLEMENTARY DATA

Video 1. Corneal haze reflects the light from a conventional surgical microscope and hinders visibility inside the eye. Light pipe spot lighting in the anterior chamber is insufficient to improve the intraocular visibility. A 25-gauge self-retaining chandelier fiber is set at the corneal limbus with the tip inside the anterior chamber through a small side-port incision. Sclerotic scattering-like illumination from the sclerocorneal margin and endoillumination from the anterior chamber, both generated by the chandelier illumination fiber, offers sufficient lighting to clearly view the anterior chamber and the corneal endothelial layer despite a hazy cornea. Descemet stripping from the recipient stroma and subsequent manipulation can be well visualized and safely carried out under chandelier illumination. Descemet membrane can be stripped as a single sheet and confirmed under chandelier illumination without biological staining.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found in the online version, at doi:10.1016/j.jcrs.2008.02.032

© 2008 by Lippincott Williams & Wilkins, Inc.