Ординатура / Офтальмология / Английские материалы / Corneal Endothelial Transplant (DSAEK, DMEK & DLEK)_John_2010

exposed donor corneal stroma blue and can be seen well even through a cloudy cornea, upon placement of the donor disk into the recipient AC (Figures 32-4 and 32-5). The freecap was then gently removed from the microkeratome head and replaced on to the exposed donor corneal stroma, such that the pre-placed marks were aligned. The outer cylinder in the AAC was then rotated into the unlocked position. The corneal button with the outer corneal cap was then removed from the AAC and it was placed on a Hanna corneal punch with the epithelial side down (Moria Inc., Antony, France).

Looking through the central opening in the Hanna trephine the surgeon could see the area of blue staining. Trypan blue only stained the cut stromal surface and the surrounding epithelium remained unstained. The blue coloration helped in the centration of the trephine and prevented any eccentric trephination of the donor corneal disk. Centration was more critical with a larger diameter trephine, such as a 9.0 mm diameter trephine, as compared to a smaller trephine, such as a 7.5 mm trephine blade. With a 9.0 mm trephine, there is a greater potential for eccentric trephination as compared to a smaller 7.5 mm trephine. The circular blade should land within the area of blue coloration to obtain a properly cut donor corneal disk and avoid eccentric trephination of the donor corneal disk.

A temporal approach was used in all cases. Following trephination of the donor cornea from the endothelial side, the trephine blade edge was ink-marked, and the recipient corneal surface on the epithelium was marked using the same diameter trephine as used on the donor cornea. Alternatively, the low-profile, John DSAEK corneal marker (ASICO Inc., Westmont, IL) was used to mark the recipient cornea. The subsequent descemetorhexis was performed using the John Dexatome spatula in all cases (ASICO Inc., Westmont, IL), 0.5 mm within this circular mark, such that the host Descemet’s membrane (DM) skirt covered the edge of the donor disk 360 degrees without any area devoid of DM, and thus prevented any postoperative peripheral corneal edema.

Conjunctiva and Tenon’s membrane were cut in the temporal region to expose the bare sclera. Complete hemostasis was achieved using a disposable cautery. A Castroviejo caliper was ink-marked at the tips with a marking pen, and the marks were placed at the perilimbal sclera, with a chord length of 5.0 mm. A curvilinear incision was then made at the limbus using a 350 µm fixed-depth diamond blade. A peripheral intracorneal pocket was created in the temporal region using an angled crescent blade (Alcon Inc., Fort Worth, TX). The AC was not entered at this time. Two stab-incisions were made at the limbus, one to the right (about 2:00 o’clock position) and a second-

stab incision was made on the left side of the temporal incision (about 5:00 o’clock position) using a 15-degree superblade (Alcon Inc., Fort Worth, TX). The 2:00 o’clock incision was used to inject the Healon and the 5:00 o’clock incision was used to inject air to unfold the “taco-folded” donor disk within the AC. These incisions were also used to introduce other instruments such as a John Dexatome spatula (ASICO Inc., Westmont, IL), reverse Sinskey hook, John super micro-scissors (ASICO Inc., Westmont, IL), John super-micro forceps (ASICO Inc., Westmont, IL), etc. as needed.

Descemetorhexis was performed under a Healon-filled AC. Descemet’s membrane was scored using the John Dexatome Spatula (ASICO Inc., Westmont, IL) first in a clockwise direction, followed by a counterclockwise scoring to complete a 360-degree scoring of the DM that was about 0.5 mm inner to the circular mark on the corneal surface. John Dexatome Spatula allowed easy Descemetorhexis, 360-degrees from a single wound entry into the AC, without exiting the AC, and without using a second instrument such as a Descemet’s stripper. Following 360-degrees scoring of the DM, the DM was then detached as a single disk and it was removed from the AC using the John EK/DSAEK insertion forceps (ASICO Inc., Westmont, IL). The John Dexatome Spatula allowed for the Descemet’s membrane to be removed as a single, complete disk, almost 100% of the time, except, in occasional cases with severe focal DM adhesions due to scarring from previous penetrating keratoplasty (PKP), such as in cases of failed corneal graft. In such cases, the John supermicro forceps (ASICO, Westmont, IL) and the John supermicro scissors (ASICO, Westmont, IL) helped to release the Descemet’s membrane in these areas of focal scarring and allowed the removal of the Descemet’s membrane as a single disk. Next, the AC was entered through the temporal pre-made groove, using a 3.2 mm keratome blade (Alcon Surgical, Fort Worth, TX). The detached Descemet’s membrane disk was then removed from the AC using a John insertion forceps (ASICO, Westmont, IL) and quickly examined under the microscope to confirm the removal of the Descemet’s membrane as a single disk.

Peripheral stromal scrubbing was performed within the epithelial circular mark to increase adhesion of the donor corneal disk to the exposed host corneal stroma. The author (TJ) performed peripheral scrubbing of the host corneal stroma routinely using a John scrubber (ASICO, Westmont, IL). This technique of peripheral stromal scrubbing was first described by Terry.48 During the scrubbing of the peripheral stroma, Healon remained in the AC to prevent AC collapse. Following stromal scrubbing, Healon was completely removed from the AC using an irrigation/

aspiration unit attached to the Alcon Legacy phacoemulsifier (Alcon Surgical, Fort Worth, TX). Healon was also removed from the inner corneal surface. The temporal peri-limbal wound was then enlarged to its full length of 5.0 mm using the angled crescent blade, bevel-up (Alcon Surgical, Inc., Fort Worth, TX). The donor corneal disk was brought to the surgical field and placed on the host corneal dome, such that the epithelial surface of the donor corneal disk was in contact with the host corneal epithelium. A small amount of Healon was placed on the endothelial surface in the center of the donor disk. One edge of the donor corneal disk was held with the John insertion forceps (ASICO Inc., Westmont, IL) and the donor disk was folded on itself in the shape of a “taco” (Figure 32-3). The donor disk was folded into a 60%/40% overfold such that the trypan blue stained stromal surface was facing up. The folded donor taco corneal disk was then introduced into the recipient AC in one continuous, smooth motion, and it was deposited on the iris surface (Figure 32-4), past the pupillary margins and the John insertion forceps was withdrawn out of the AC. The peri-limbal wound was closed with three interrupted, 10-0 nylon sutures. A 30-gauge sterile cannula was introduced from the previously placed stab incision at the 5:00 o’clock position, and the tip of the cannula was placed between the leaflets of the folded taco. Filtered-air was gently injected in a gentle, steady stream to unfold the taco completely (Figure 32-5) and attach the donor corneal disk to the host corneal stroma. If the donor corneal disk was decentered (Figure 32-5), centration of the donor disk was achieved (Figure 32-6) using a reverse Sinskey hook. Following proper attachment and centration of the donor corneal disk a waiting period of 8 to 10 minutes was allowed to further facilitate donor disk adhesion.

Results

ICG helped in better visualization of the donor disk within the recipient anterior chamber during DLEK, due to the green color of the stained donor stromal surface (Figure 32-2). Further ICG stained disk was easier to position properly within the host cornea as compared to those cases where ICG was not used. The day after surgery there was no ICG visible in any of the cases by slit-lamp examination. ICG disappears within 24 hours after surgery. There was no increased anterior chamber inflammation in any of the cases as compared to DLEK without ICG. The donor corneal disk edges and the interface were better approximated in the ICG cases as compared to the non-ICG cases. There was no posterior segment toxicity noted in any of the cases

from the ICG use. Similarly, the use of trypan blue during DSAEK surgery helps to easily visualize the donor cornea even through a cloudy cornea (Figures 32-3 to 32- 6).

Discussion

ICG has been widely used in various medical fields, including cardiovascular, hepatic and ophthalmic specialties.18 ICG has been used both in animal19-26 and human studies.27-31 In ophthalmology, it has been used initially for ophthalmic angiographic studies27 and more recently to stain the anterior lens capsule32 under air before capsulorhexis during phacoemulsification. When this solution of ICG is used in the anterior chamber under air, the aqueous humor that is in the anterior chamber immediately dilutes the injected dye within the anterior chamber. Since dilution does not take place when the dye is directly added to the exposed corneal stroma of the donor corneal disk attached to the ACC, the dye is further diluted 1:1 with sterile BSS before its direct use on to the corneal stroma of the donor cornea.

Following donor corneal exposure to this dye, it stains only the exposed donor corneal stroma and it does not stain the uncut, full-thickness, donor corneal rim with its intact epithelium. Such selective staining of the donor corneal stroma provides an added advantage to the corneal surgeon in proper placement and centration of this donor disk on the Teflon block before trephination. The trephine that is used to trephine the donor disk is 8.0 mm in diameter. The exposed corneal stroma is 9 mm in diameter. This allows only a 0.5 mm margin on all sides of the donor disk to trephine within the exposed corneal stroma. Any eccentric trephination will carry with it the uncut corneal rim at the eccentric margin that will then have to be manually trimmed with scissors. Manual trimming can cause irregularities and result in improper approximation of the donor disk to the host cornea creating irregularities in the newly created corneal interface. Since the disk is stained with the dye in a circular area 9.0 mm in diameter, this allows for good centration of this disk on the Teflon block to match the ring mark on the Teflon block and allows for the 8.0 mm trephination to be carried out well within the 9.0 mm corneal stained area and prevents any eccentric cut. This eliminates any inadvertent cutting of the peripheral full-thickness donor cornea.

Staining of the corneal donor disk with the ICG allows good visualization of the donor disk in the host anterior chamber through the host anterior corneal stroma. Before this staining technique, the visualization of the donor disk within the host anterior chamber was suboptimal and made it very difficult for the corneal surgeon to properly

approximate the donor disk to the host corneal opening. This staining technique greatly facilitates this surgical technique and helps in proper positioning of the donor disk within the recipient cornea.

ICG is a sterile, water soluble, tricarbocyanine dye with a peak spectral absorption of 800-810 nm in blood plasma or blood.33 ICG is taken up from the plasma almost exclusively by the hepatic parenchymal cells and is secreted entirely into the bile. 27 ICG contains not more than 5.0% of sodium iodide.33 ICG is marketed for intravenous administration. Anaphylactic or urticarial reactions have been reported in patients with or without a history of allergy to iodides.33 If reactions occur, treatment with appropriate agents, e.g. epinephrine, antihistamines, and corticosteroids, should be initiated. It is unknown whether this drug is excreted in human milk,33 and caution should be exercised when ICG is administered to a nursing woman.33 However, in the present method of ICG usage described in this chapter a dilute solution is used to stain the donor disk, and the excess dye is removed before placement of the stained disk into the anterior chamber of the host. This is a negligible amount of the dye that is already adhering to the cornea as compared to the larger dose that is used for ophthalmic angiography.

DLEK is a relatively new anterior segment surgical procedure that may selectively replace PKP in a subset of patients to visually rehabilitate those individuals with corneal endothelial decompensation and corneal edema.

There are several advantages to the intraoperative use of ICG dye to stain the donor corneal stroma (Table 32-1). ICG greatly facilitates performing this new surgical procedure and contributes to a good postoperative result.

TABLE 32-1: Advantages of intraoperative use of ICG in DLEK

Advantages

1.Instant staining of donor corneal stromal tissue from clear to green.

2.The staining step takes less than 60 seconds and with no significant surgical delay.

3.ICG disappears from the host cornea within 24 hours following surgery.

4.Helps confirm that the donor corneal disk is in the host anterior chamber.

5.Helps in good approximation of donor stromal tissue to the recipient corneal stroma.

6Facilitates good coaptation of donor-host graft margins 360 degrees.

7Helps to visualize any interface fluid pocket, air, or debris.

Trypan Blue

In 2004, Food and Drug Administration approved the use of Vision Blue (Trypan Blue ophthalmic solution) (Dutch

Ophthalmic International, Exeter, NH, USA) for staining of the anterior lens capsule during cataract surgery. Trypan blue has various surgical and laboratory applications.34-47 Georgiadis et al34 used trypan blue to stain donor cornea and evaluate their suitability for human corneal transplantation. Subsequently in 2002, Balestrazzi et al35 first used trypan blue to stain the human corneal stroma during anterior lamellar keratoplasty. In 2004, Food and Drug Administration approved the use of Vision Blue (Trypan Blue ophthalmic solution) (Dutch Ophthalmic International, Exeter, NH, USA) for staining of the anterior lens capsule during cataract surgery. Trypan blue has

various surgical and laboratory applications.34-47 Trypan blue, also known as diamine blue and Niagara

blue, is a stain used to selectively color dead tissues or cells.40 It cannot transverse the membrane of live cells but does through membranes of dead cells and therefore, only the dead cells are shown with a distinctive blue color.40 In the present study the donor corneal cells are viable as assessed by the distributing eye banks. Therefore, the selective staining of the cut stromal surface may be due to the presence of glycosaminoglycans and other cellular matrix substances present in the corneal stroma. Trypan blue does not stain the surrounding intact corneal epithelium. This selective staining of the cut stromal surface is beneficial to the surgeon throughout the ET procedure. However, this is an off-label use of trypan blue.

In addition to laboratory uses of trypan blue, it is used in various anterior and posterior segment ophthalmic procedures including capsulorhexis prior to phacoemulsification (especially in the absence of a red reflex), perioperative staining of the corneal endothelium, staining of internal limiting membrane and epiretinal membrane in vitrectomy, and evaluation of corneal graft tissue. 34-47

Ocular toxicity due to the use of trypan blue has been studied.41 In vitro studies have shown that rat neurosensory retina (R28) cells are more sensitive than human retinal pigment epithelial cells (RPE) (ARPE-19) to trypan blue. 41 Human RPE cells showed no evidence of toxicity to four different concentrations of trypan blue (0.1%, 0.05%, 0.025%, and 0.0125%) in vitro. 41 Trypan blue has also been evaluated in vitreoretinal surgery.39 The application of trypan blue onto the internal limiting membrane (ILM) and epiretinal membranes (ERM) in vitreoretinal surgery resulted in a useful bluish staining, facilitating the identification, delineation, and removal of the membranes in all surgeries.39 However, no residual staining or adverse effects related to the dye were observed.39 No adverse effects were noted when trypan blue 0.02% was used in vivo, inside the eye, or in postmortem, histological studies.42 However,

when trypan blue was used at concentrations of 0.15% and 0.25% there was disorganization of the inner retinal layers and the ILM was absent in the postmortem studies.42 Vision blue (Trypan blue, Dutch Ophthalmic, USA) is commercially available at a concentration of 0.06%. The risks include potential staining of high water content hydrophilic acryclic intraocular lens, and inadvertent staining of the posterior lens capsule and vitreous face. The staining of the posterior lens capsule and vitreous face is usually self-limited and can last up to 1 week. The use of Vision Blue in the donor corneal stromal staining in DSAEK procedures has not been associated with any known permanent intraocular damage. Unlike in cataract surgery where it is used directly in the anterior chamber to stain the anterior lens capsule under filtered-air, in DSAEK the staining of the donor corneal stroma is done outside the eye and the area of staining then comes into apposition with the recipient inner corneal stroma at the donorrecipient interface. Such staining of the donor corneal stroma has not been associated with any interface adverse

effects that is seen clinically.

Selective staining of the donor corneal stroma aids in proper alignment and centration of the disposable tryphine during donor corneal tryphination. This further helps to prevent eccentric tryphination of the donor corneal disk. Further, if the donor disk unfolds to the wrong side, i.e. the donor endothelium facing up towards the inner surface of the recipient cornea, the trypan blue staining will help identify the stained stromal side from the unstained donor endothelium. Trypan blue can be used for staining of patient’s Descemet’s membrane as well. However, we do not recommend staining of both the donor corneal disk and Descemet’s membrane of patient’s cornea, as it would be difficult to distinguish the two and could lead to error and potential complications.

We recommend the use of trypan blue ophthalmic solution to corneal surgeons who perform EK surgery to facilitate viewing the donor corneal disk through the patient’s cloudy cornea. Trypan blue appears to be safe in the staining of donor corneal stroma during EK surgery.

Summary and Conclusions

The use of dye, namely, trypan blue (Vision Blue, Dutch Ophthalmic USA), or ICG to stain the donor corneal stroma is recommended for ET surgery. The use of these dyes for corneal staining is an “off-label” use of the drug in the United States. Staining the donor corneal stroma greatly improves the visualization of the donor corneal disk

through a cloudy cornea. The use of such dyes as described, appears to be clinically safe and there have been no clinically observable adverse side-effects from its use.

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Introduction

Improved vision is the goal in the vast majority of patients undergoing corneal transplantation. Any of the cornea’s 5 layers can be the underlying source of decreased corneal transparency. Endothelial dysfunction is the most common indication for penetrating keratoplasty (PKP). Loss of the non-regenerating, single-layered endothelium results in stromal edema. This deterioration of endothelial-pump function may be gradual at first, with only morning edema with minimal loss of vision, but over time, classically worsens to gross bullous keratopathy, with severe loss of vision and the patient may also have intermittent pain due to rupture of bullae. In Fuchs’ dystrophy, edema is preceded typically with central guttata, which by themselves contribute to loss of visual function. Acute loss of endothelium can also result from a variety of surgical mishaps and rarely viral infections. Regardless of the etiology, loss of endothelial function always precipitates stromal edema and subsequent loss of corneal clarity and visual acuity. The only therapeutic procedure is replacement of the endothelium with donor tissue, i.e. corneal transplantation.

In my practice, which typifies the western world, the most common indications for corneal transplantation secondary to endothelial failure are the following in numerative order; 1) Fuchs’ endothelial dystrophy with endothelial decompensation, 2) pseudophakic bullous keratopathy (PBK)/aphakic bullous keratopathy (ABK), 3) failed graft (PKP or DSAEK), 4) other (ICE syndrome). Most patient’s symptoms, unless acutely caused by an intraocular surgery such as phacoemulsification, typically experience gradual loss of vision from worsening corneal edema. The decision to undergo corneal transplantation is therefore elective, depending on the patient’s symptoms and informed consent as to the risk-benefit ratio of surgery. This ratio is key in determining the timing of transplantation. Historically, surgical success has defined the indications for surgical intervention. As an example, cataract couching was delayed until the cataract was ripe (almost gross blindness). In the early 1980s, with intracapsular cataract extraction and no IOL surgery, the surgical bar was raised to visual acuity less than than 20/70. Presently, 20/20 clear lensectomy for refractive indications with modern phacoemulsification techniques and multifocal IOLs are accepted by surgeons and patients alike.

Similarly, modern microsurgery and eye banking advancements have elevated the surgical bar for present day penetrating keratoplasty (PKP) for endothelial disease. If success is defined as just obtaining an anatomically clear donor button, then PKP, the standard of care for the last 50

years, is highly successful. However, if success is defined as the recovery of excellent functional vision, then the success rate plummets. Functional visual recovery requires not only a clear corneal donor button, but predictable and regular surface keratometry. The full-thickness trephinations of PKP commonly induce irregular astigmatism, only correctable with a rigid contact lens. The resultant corneal power is unpredictable, often inducing unacceptable anisometropia. Long-term sutures and the slow healing rate of the avascular cornea delay final refractive outcome. Suture breakage or removal results in a large refractive shift, sometimes deleterious for the patient. Surgically induced neurotrophic keratitis can diminish vision from surface disease. Late traumatic wound rupture can have devastating results, often with loss of the globe.

Avoiding the visual risks of PKP has led to the surgical development of the posterior lamellar keratoplasty (PLK) techniques, such as deep lamellar endothelial keratoplasty (DLEK), and Descemet stripping automated endothelial keratoplasty (DSAEK). They are small limbal incision techniques that eliminate full-thickness trephinations and transplant only a donor endothelial layer with some accompanying posterior stroma. By and large, DSAEK has supplanted DLEK as the preferred technique because of its surgical consistency and improved visual results. DSAEK incision size has been reduced to just over 3 mm, similar to clear corneal phacoemulsification incisions (Editorial Note: Unlike a phacoemulsification incision, with a DSAEK incision, with decreasing size from a 5.0 mm wound to a smaller wound size, there appears to be an increase in the endothelial cell loss due to mechanical tissue compression). Without surface penetrating trephinations, the refractive irregularities and unpredictabilities of the procedure have been eliminated. Corneal clarity is excellent within weeks and continues to improve over the first 3 months in most patients. The surgical bar has been lowered and less severe visual disability is not a barrier to surgical intervention. The visual outcomes following fullthickness and partial-thickness corneal transplantation are shown in Figures 33-1 and 33-2.

PKP Visual Recovery

The surgical bar in my practice for PKP surgery is 20/70 BCVA. Of course, this is just a guideline and patients always make the final decision. In the state of Florida, this decision is often tied to the minimum visual acuity that is required for a driver’s license, which is 20/70 in both eyes if the best eye is less than 20/40. I counsel patients that final visual outcome is typically delayed to over 1 year or longer. Depending on their BSCVA, the running suture is left in place indefinitely and a GPCL is often required,

Figure 33-1: Relative visual acuities following penetrating keratoplasty (PKP), deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), and Descemet stripping automated endothelial keratoplasty (DSAEK).

the patient and donor corneas in DLEK; 2) the visual recovery of DSAEK is more rapid. The originally higher donor dislocation rate of DSAEK compared to DLEK, has been eliminated with further surgical modifications and surgeon experience. However, DLEK greatly improved the quality and rate of visual recovery over PKP by eliminating full thickness trephinations.

Based on the results of only one experienced DLEK surgeon, BSCVA recovered to the 20/40 -20/60 range by 6 months. Surface topography was regular and predictable and the limiting factor for faster recovery was the interface wound, which continued to improve for over 1 year postoperative. This was a vast improvement over the results obtained with PKP, except that no patients achieved 20/20 vision. Other advantages of DLEK over a PKP include a relatively small 5 mm limbal incision, without induced neurotrophic surface problems or suture-related complications.

Figure 33-2: At one year following surgery, percentage of best corrected visual acuity (BCVA) of 20/40 or better following penetrating keratoplasty (PKP), deep lamellar endothelial keratoplasty (DLEK), and Descemet stripping automated endothelial keratoplasty (DSAEK).

usually not for at least 3 months, but this may be delayed until the suture is removed at 1 year the earliest.

Additional refractive procedures are often required to improve the visual quality, such as relaxing incisions, compression sutures or LASIK. This causes further delay and adds uncertainty as to the final visual outcome. If the condition is bilateral, I do not recommend the second eye for surgery until the first eye is the better eye. This unpredictable quality and rapidity of their visual recovery is the driving force behind these conservative recommendations.

DLEK/PLK Visual Recovery

DLEK is the forerunner of DSAEK, and has largely been replaced by it. The reasons are twofold; 1) DSAEK eliminates the difficult manual lamellar dissections of both

DSAEK Visual Recovery

DSAEK has quickly become the dominant procedure for endothelial keratoplasty. Despite a significant learning curve and capital equipment outlay ( unless donor cutting done by eye bank), it provides the best visual quality at the fastest pace of all keratoplasty techniques. Built upon the surgical ideas of DLEK, it also eliminates full-thickness trephinations of PKP, thereby leaving undisturbed the normal surface anatomy. It improves upon DLEK by eliminating all manual lamellar dissections. This increases the reproducibility of the procedure. Visual quality is enhanced by the regularity of the interface tissues. Descemet stripping leaves a pristine smooth recipient surface. The keratome cuts an extremely regular surface on the donor, equal to the quality of LASIK flaps. Incision size has been reduced to 3.2 mm, close to the typical phacoemulsification incision size (Editorial Note: Compared to 3.2 mm incision in DSAEK, a 5.0 mm incision causes less donor corneal endothelial cell loss).

In my patients, when macula or optic nerve pathology is eliminated, the rate of visual recovery is extremely rapid. Over 80% of patients usually achieve a BSCVA of 20/40 by 6 weeks and this increases to over 90% by 3 months. While 20/20 is obtained by only 16% of patients, over one-third usually reach 20/25 in the first 6 months. This compares favorably to DLEK, with only 28% reaching 20/40 at 6 months and none at 20/20. However, the one year DLEK data continues to improve, narrowing this gap. The visual recovery of DSAEK is so predictable, the interface wound so imperceptible, that a patient who fails to reach a

postoperative Snellen milestone should be evaluated for undetected macular disease.

The improved visual recovery of DSAEK patients, compared to those of PKP patients has caused a paradigm shift in the recommendations to prospective surgical candidates. The surgical bar has been lowered, not dissimilar to the evolutionary rise seen with improved cataract surgery techniques. Patient complaints, consistent with their corneal disease, now drive the decision toward surgery. Rather than a conservative 20/70 minimum visual acuity used for PKP counseling, in Fuchs’ dystrophy, dense guttata, decrease visual quality which is not accurately depicted by Snellen acuity may be part of the surgical considerations. My “second eye rule”, refers to deferring surgery on the second eye until the first eye is the better eye. With DSAEK, patients are routinely requesting surgery for their second eye as early as 2-3 months following surgery, even if the Snellen acuity in the operated eye is less than the

unoperated eye. The postoperative visual quality is now superior with DSAEK surgery as compared to PKP. This is not too dissimilar to patients with posterior sub-capsular cataracts who are significantly disabled by their vision in spite of near normal Snellen measurements. Glare and contrast are important clinical indicators of patient satisfaction. Like DLEK, refractive surprises are usually non-existent. There appears to be a small early hyperopic shift of1.0-2.0D (Editorial Note: Usually 1.0 diopter or less) that partially fades over the first 3 months. Rigid contact lenses are unnecessary as there is no induced irregular astigmatism. Spectacle correction can be given confidently by 3 months postoperative. The functional recovery is consistent, with less than 10% not reaching 20/40 BSCVA. ThiscomparesveryfavorablytoPKPforFuchs’diseasewith 36%failing to achieve 20/40 BCVA(15% requiredcontacts). Long-term results only extend to 2 and ½ years and NEI sponsored endothelial cell count study is in progress.