Deep Lamellar Endothelial Keratoplasty Research Articles

Graft failure: I. Endothelial cell loss

Graft failure through endothelial cell loss is a constant threat throughout the lifetime of a corneal graft. It can occur at various time points after transplantation. Primary graft failure has nowadays become increasingly rare owing to meticulous eye banking methods and improved surgical techniques. Corneal graft rejection is always held responsible for endothelial cell loss. However a rejection episode that is promptly and adequately treated does not necessarily lead to a higher than expected cell loss. A more smouldering danger to ultimate graft survival is late endothelial failure. This gradual graft decompensation is secondary to a decrease in cell density below that necessary to maintain corneal deturgesence. The process of transplantation itself seems to set off a series of events (possibly immunological) that greatly exacerbates the endothelial cell loss compared to virgin corneas. This accelerated cell loss persists for at least 10-15 years after transplantation, after which a more-stable situation is reached and cell attrition returns to normal rates. This provides a strong rationale for setting high donor standards of minimal cell density. Newer transplantation techniques such as deep anterior lamellar keratoplasty and deep lamellar endothelial keratoplasty could provide possible solutions to prevent this late endothelial failure. However they still have to prove themselves in the long run.

Evaluation of Deep Lamellar Endothelial Keratoplasty Surgery Using Scatterometry and Wavefront Analyses

To determine if postsurgical corneal interface abnormalities after deep lamellar endothelial keratoplasty (DLEK) cause increased light scattering or wavefront aberrations that may help to explain decreased best-corrected visual acuity in DLEK patients compared with penetrating keratoplasty (PK) patients. Prospective comparative case series. Clinically clear corneas of 4 eyes that had undergone DLEK surgery and 4 eyes that had PK were studied. Normal control data for light scattering was collected from 12 right eyes and 11 left eyes with normal corneas. Corneal light scattering was measured with a scatterometer designed at the Johns Hopkins Applied Physics Laboratory, and wavefront analysis was performed using standard methods with a Hartmann-Shack wavefront sensor. Corneal scattering measurements were normalized by taking the ratio of the subject's corneal light scattering to a reference material. A scattering index was calculated as the ratio of the normalized scattering for a given patient's cornea to the average scattering of normal corneas. Astigmatism and higher-order aberrations were analyzed using standard data output from wavefront analysis and Zernike polynomial decomposition. The mean scattering index was significantly higher after DLEK (1.78+/-0.29, mean+/-standard deviation [SD]) than after PK (1.03+/-0.27; P = 0.043). The higher-order root mean square (RMS) wavefront error was significantly higher after PK (0.71+/-0.11 microm, mean+/-SD) than after DLEK (0.44+/-0.12 microm; P = 0.029). Zernike polynomial decomposition of the wavefront aberrations revealed that regular corneal astigmatism was the most important aberration component for both PK and DLEK, but the PK patients had significantly more regular astigmatism (1.7+/-0.45 diopters [D], mean+/-SD) than did the DLEK patients (0.84+/-0.27 D; P = 0.029). Our data quantitatively support subclinical corneal haze as an explanation for the limited visual acuity after DLEK as compared with PK. Intraoperative or postoperative modifications to reduce stromal haze after DLEK may result in better visual acuity outcomes.

A Prospective Study of Endothelial Cell Loss during the 2 Years after Deep Lamellar Endothelial Keratoplasty

To report the endothelial survival over a 2-year period after 2 techniques of deep lamellar endothelial keratoplasty (DLEK) in the treatment of endothelial dysfunction. Prospective, noncomparative, interventional case series. One hundred eyes of 88 patients with corneal edema. One hundred consecutive eyes with endothelial failure were entered into a prospective study of endothelial keratoplasty, and the donor central endothelial cell density (ECD) was recorded postoperatively at 6 months (n = 98), 12 months (n = 96), and 24 months (n = 85) and then compared with the preoperative eye bank measurements. The subsets of eyes with large-incision DLEK (n = 36) and small-incision DLEK (n = 62) were also evaluated and compared. Preoperative and postoperative central ECDs were prospectively evaluated and the cell loss calculated for each postoperative time point. The average (and standard deviation) ECD at 6 months was 2140+/-426 cells/mm(2), representing a mean cell loss from preoperative donor cell measurements of 25+/-15%. At 12 months, ECD was 2090+/-448 cells/mm2 (26+/-16% cell loss), and at 24 months, it was 1794+/-588 cells/mm2 (37+/-27% cell loss). The additional cell loss from 1 to 2 years was significant (P<0.001). In the subset of large-incision DLEK eyes (n = 36), the cell loss from preoperatively to 6 months was 23%; 12 months, 22%; and 24 months, 27%. In the subset of small-incision DLEK eyes (n = 62), the cell loss from preoperatively to 6 months was 25%; 12 months, 28%; and 24 months, 43%. The cell loss from small-incision DLEK surgery was significantly greater than that from large-incision DLEK surgery at the 12-month (P = 0.013) and 24-month (P<0.001) postoperative measurements. Although the initial cell loss from DLEK surgery is minimally changed from 6 to 12 months postoperatively, there is an acceleration of cell loss from 1 year to 2 years postoperatively. The small-incision DLEK technique, which involves folding of the donor tissue, results in a significantly higher endothelial cell loss at 1 and 2 years than that found after large-incision DLEK surgery, wherein the tissue is not folded.

Early Results of Small-Incision Descemet’s Stripping and Automated Endothelial Keratoplasty

To describe our technique and early results of Descemet's stripping and automated endothelial keratoplasty (DSAEK), identify perioperative complications, and discuss their management. Prospective, noncomparative, surgical case series. Twenty-six eyes of 26 patients who had corneal edema from Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy, or aphakic bullous keratopathy. The donor corneal lenticule was prepared using a microkeratome and an artificial anterior chamber maintainer. Stripping of the diseased host endothelium was performed under viscoelastic using a 2.75-mm clear corneal temporal incision. The incision was enlarged to approximately 4.2 mm to allow placement of a folded 8.5-mm-diameter donor corneal lenticule. The donor graft was positioned using a temporary air bubble that was partially evacuated after 7 minutes. The corneal wound was closed with a single 10-0 nylon suture. Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry, topographic astigmatism, corneal pachymetry, and perioperative complications. Three months postoperatively, all donor grafts remained clear. The average 3-month postoperative BSCVA was 20/45 (range, 20/20-20/150). The average change in refractive astigmatism was 0.12+/-1.15 diopters (D) (range, -1.50 to 3.25). In patients who underwent simple DSAEK (i.e., no intraocular lens implantation), the average postoperative shift in spherical equivalent refractive error was 1.15+/-1.35 D (range, -0.25 to +4.25). Nine of 26 initial grafts dislocated postoperatively and had to be repositioned. Three of the repositioned grafts dislocated again and were replaced with new donor corneal lenticules, all of which remained clear. Descemet's stripping and automated endothelial keratoplasty uses a mechanical microkeratome to harvest the donor corneal lenticule and mechanical stripping of the diseased host endothelium and Descemet's membrane. Despite a smooth graft-host interface, only 2 patients in the series achieved > or =20/25 vision. The average visual results were comparable to vision after deep lamellar endothelial keratoplasty. Although patients experienced excellent postoperative acuity with minimally induced surgical astigmatism, nearly one third of the donor lenticules needed to be either repositioned or replaced. Nevertheless, DSAEK offers significant advantages over standard penetrating keratoplasty for patients with Fuchs' dystrophy in pseudophakic bullous keratopathy.

Spontaneous Resolution of Partial Donor Disk Dislocation After Deep Lamellar Endothelial Keratoplasty

We report a case of spontaneous resolution of donor disk partial dislocation after deep lamellar endothelial keratoplasty (DLEK). Case report. A 70-year-old male with right pseudophakia bullous keratopathy underwent DLEK. Postoperatively, a partial dislocation of inferior donor disk was noted. Repositioning surgery with gas tamponade was performed. The interfacial separation remained after gas tamponade. Two weeks later, corneal edema subsided, and there was a reduction in interfacial separation. One month after DLEK, donor disk spontaneously attached to recipient corneal bed. At the six-month follow-up, astigmatism was 1.75 diopters. Specular microscopy showed endothelial counts of 1520 cells/mm(2). Spectacle-corrected visual acuity improved to 6/15. Partial dislocation of donor disk after DLEK has a possibility of spontaneous resolution, even after a failed attempt at gas tamponade.

Endothelial keratoplasty: redefining the surgical therapy of endothelial dysfunction

Deep lamellar endothelial keratoplasty (DLEK) and Descemet’s stripping EK (DSEK) are rapidly replacing penetrating keratoplasty (PKP) in cases where endothelial dysfunction is the main reason for intervention. DLEK and DSEK offer many benefits over standard PKP. The endothelial layer of the host cornea is removed through a small scleral–limbal incision and, through the same wound, a lamellar endothelial donor graft is inserted into the anterior chamber and attached to the endothelial surface of the host cornea without the use of any sutures. The surgical wound is more stable, with less corneal topographic alteration than one made in PKP. In addition, patients who have undergone DLEK or DSEK have a more rapid visual recovery and a simpler postoperative course than those who have undergone PKP.

Histology of Dislocations in Endothelial Keratoplasty (DSEK and DLEK)

Laboratory studies were performed to evaluate the histologic differences between the recipient bed after deep lamellar endothelial keratoplasty (DLEK) surgery and Descemet's-stripping endothelial keratoplasty (DSEK) surgery. Relevant new surgical strategies to prevent dislocation in DSEK surgery were initiated in our first 100 consecutive clinical cases. Ten pairs of cadaver eyes had a DLEK in 1 eye and a DSEK in the fellow eye, and the posterior stromal surface was analyzed by scanning electron microscopy at x50 magnification. Based on the findings in these cadaver eyes, our DSEK procedure was modified to include surgical roughening in the peripheral recipient bed in 100 consecutive eyes. One hundred percent of these eyes were followed for at least 60 days after surgery to determine the rate of donor dislocation. In all 10 pairs of cadaver eyes, the DSEK stromal interface showed a smoother surface than DLEK eyes, without the presence of cut stromal fibrils. The DLEK surface was less smooth than the DSEK eyes, but with the presence of uniformly cut fibrils over the entire surface. Subsequent surgical modifications to the DSEK procedure to include scraping and roughening of the recipient peripheral bed in humans resulted in only a 4% (4/100) dislocation rate of the donor tissue into the anterior chamber. One of these 4 dislocated donors was seen on the first postoperative day and was the only primary graft failure in the series. The other 3 cases were fully attached on the first postoperative day with no interface fluid, but they dislocated later on postoperative days 2, 3, and 4. The high rate of dislocation of the donor disc in DSEK may be caused by the absence of recipient stromal fibrils to initially bind to the donor stromal fibrils. Clinical success with a surgical technique of selectively scraping the peripheral recipient bed to promote donor edge adhesion (while leaving the central bed untouched for vision) may aid in the prevention of donor dislocation in DSEK surgery. Reduction of dislocation in DSEK surgery has also been associated with a reduced rate of iatrogenic primary graft failure (PGF) to 1%.

Histopathological study of corneal wound healing in guinea pigs after deep lamellar endothelial keratoplasty with small incision

To study the histopathological characteristics of corneal wound healing after deep lamellar endothelial keratoplasty (DLEK) with small incision. Forty-five guinea pigs were divided into the donor and recipient groups, which consisted of 15 and 30 guinea pigs respectively. DLEK was performed in the right eye, and the left eye was used as histopathological control. Two guinea pigs with clear right corneas under biomicroscopy examination were killed at 1 week, 2 weeks, 1 month, 2 months, 3 months and 4 months postoperatively, separately. Bilateral corneal buttons were harvested for the evaluation of endothelial cells (alizarin red stain) and for the light microscopy study (HE or PAS staining). Clear cornea could be obtained in 22 recipient eyes postoperatively. In these corneas, the endothelial cells either in the donor disc or recipient's bed were normal in shape and size. However, there was a band area between the donor disc and recipient's bed, where the endothelial cells were abnormal. In the early postoperative period, histopathological study disclosed increase of number of cells in the corneal stroma along the pathway of lamellar separation. The tissue connecting the gap between the donor and recipient lacked lamellar structure. The new descemet's membrane appeared beneath the endothelium 1 month postoperatively. Three to four months after the operation, the continuity of the descemet's membrane and the posterior lamella was rehabilitated. The corneal wound healing process after the DLEK with small incision is related with the type of trauma. Collagen is arranged well at the surface of the lamellar. Fibrotic repair is seen in the marginal area connecting the donor disc and recipient's bed.

Corneal Graft Folds: A Complication of Deep Lamellar Endothelial Keratoplasty

Corneal Graft Folds: A Complication of Deep Lamellar Endothelial Keratoplasty

Deep lamellar endothelial keratoplasty: early complications and their management

The authors reviewed the first 100 consecutive patients to reach the 6-month postoperative gate of a prospective series of patients undergoing deep lamellar endothelial keratoplasty (DLEK) for endothelial decompensation from Fuchs’ dystrophy or pseudophakic bullous keratopathy and no significant anterior corneal scarring. Two eyes were converted to penetrating keratoplasty at the time of DLEK surgery. Among 98 successfully completed DLEK procedures, four (4%) eyes had a dislocated disk on the first postoperative day which was repositioned without complication, four eyes (4%) experienced reversible endothelial rejection episodes, seven eyes (7%) required epithelial scraping for persistent epithelial irregular astigmatism, one patient (1%) experienced steroid-aggravated glaucoma, and one eye (1%) had primary graft failure. Eyes with postoperative disk location or endothelial rejection episodes had significantly fewer endothelial cells at 6 months than eyes that did not experience these complications (P = .003 and P = .027, respectively). There were no statistically significant differences in best-spectacle corrected vision (BSCVA) between eyes that experienced disk location or required epithelial scraping compared to those that did not, but there was a statistically significant reduction in BSCVA among eyes that experienced endothelial rejection episodes (P = .020). Disk replacement was successfully performed for the case of primary graft failure. There were no cases of endophthalmitis, microbial keratitis, persistent epithelial defects, late dislocation of the disk, or cataract progression. No patient required a contact lens or refractive modification of the cornea for residual refractive error. The authors conclude that the complications associated with DLEK are relatively uncommon and are easily resolved.—Michael D. Wagoner

Initial Results of Small Incision Deep Lamellar Endothelial Keratoplasty (DLEK)

To evaluate the results of replacing the posterior stroma and endothelium, using small incision deep lamellar endothelial keratoplasty (DLEK) surgical technique, in patients with corneal endothelial dysfunction. Noncomparative case series. Fifteen eyes of 15 patients (six males and nine females) with endothelial dysfunction were included in this study. Through a 5-mm scleral incision, a deep lamellar pocket was created across the cornea, followed by excision of an 8.0-mm disk of posterior lamellar corneal tissue. Same size lamellar donor disk was prepared and placed in position without the need of suture fixation. Best spectacle-corrected visual acuity (BSCVA), refraction, endothelial cell density, corneal topography, and corneal thickness were analyzed. Average BSCVA preoperative was 20/200 (range 20/40 to hand movements (HM)), improving to 20/50 (range 20/20 to 20/120) at a mean follow-up of 7.2 months. Average refractive astigmatism at last follow-up was 1.46+/-1.21 diopters (range, 0 to 4 diopters). Preoperative average donor endothelial cell density was 2047+/-311 cells/mm2, and that at last follow-up was 1732+/-514 cells/mm2. Preoperative average pachymetry was 801.4+/-211.3 microm, improving to 553+/-90.4 microm at last follow-up. Initial results with small incision DLEK procedure indicate that it is a safe procedure that provides healthy donor endothelial cell count and function postoperatively, with encouraging visual results.

Deep Lamellar Endothelial Keratoplasty

To report the early vision-threatening complications in a large series of deep lamellar endothelial keratoplasty (DLEK) procedures and discuss the management of these complications. The first 100 consecutive patients to reach the 6-month postoperative gate of a prospective, institutional review board-approved protocol for DLEK surgery were reviewed for intraoperative and postoperative complications. The method of treatment of these complications and the outcome of that treatment were recorded. Two eyes (2 of 100 = 2%) were converted to PK at the time of DLEK surgery. Of the 98 patients who had complete DLEK surgeries, 4 eyes (4 of 98 = 4%) were noted to have a dislocated disk on the first postoperative day. The dislocated disk in each case was repositioned in a short, often topical anesthesia technique, and all corneas cleared. One eye had primary graft failure (caused by surgeon error) resulting in disk dislocation. It was successfully replaced with another disk on postoperative day 1. Four patients (4 of 98 = 4%) experienced graft rejection of the donor disk from stopping steroids, but all grafts cleared with restarting of steroids. One patient required surgery for steroid-aggravated glaucoma. In the 5 cases of DLEK surgery in which the clear crystalline lens was left in place, no cataracts were induced at the 6-month postoperative gate. There were no infections, ulcerations, healing defects, or late dislocations. No patient required a contact lens, relaxing incision, or LASIK for residual refractive error. DLEK surgery is technically challenging, and yet complications from the surgery in our series were relatively rare and easily resolved. By eliminating sutures and high astigmatism, DLEK surgery avoids the usual complications often associated with transplant surgery.

Expression of Toll-like Receptors in Healthy and Allergic Conjunctiva: Discussion

Until now, the gold standard surgical procedure for posterior corneal pathology has been full-thickness corneal transplantation (penetrating keratoplasty [PK]). Deep lamellar endothelial keratoplasty (DLEK) is an alternative partial-thickness corneal transplant procedure. With DLEK, the patient’s damaged endothelium and posterior stroma are replaced with donor endothelium and posterior stroma. This procedure is designed to replace the diseased portion of the cornea and leave the healthy anterior cornea intact. Deep Lamellar Endothelial Keratoplasty: Visual Acuity, Astigmatism, and Endothelial Survival in a Large Prospective SeriesOphthalmologyVol. 112Issue 9PreviewTo report the 6-month results for the treatment of endothelial dysfunction in a large, prospective series of deep lamellar endothelial keratoplasty (DLEK) procedures. Full-Text PDF

Preparation of Donor Lamellar Tissue for Deep Lamellar Endothelial Keratoplasty Using a Microkeratome and Artificial Anterior Chamber System: Endothelial Cell Loss and Predictability of Lamellar Thickness

To measure endothelial cell loss and predictability of lamellar thickness after preparing donor tissue for deep keratoplasty with an artificial anterior chamber and microkeratome. A microkeratome set at a depth of 350 microm and a diameter of 9 mm was used to obtain ten lamellar lenticules from corneoscleral rims mounted in an artificial chamber. A punch trephine then was used to cut the donor tissue 7 mm in diameter. Specular microscopy was performed to evaluate endothelial cell density before the procedure, after cutting with the microkeratome, and after trephination. Pachymetry was performed to determine the predictability of lenticule thickness, before the procedure and after microkeratome incision. Mean post-microkeratome endothelial cell loss was 79 +/- 88 cells/mm2 and post-punch trephination was 85 +/- 94 cells/mm2. This represented a mean percentage loss of 3.2% and 3.5% for the respective steps of this procedure. Nine of the ten lenticules were cut within +/- 75 microm of the intended 350-microm thickness. Preparing donor lenticules for deep lamellar endothelial keratoplasty with a microkeratome with artificial chamber system caused a relatively small loss of endothelial cells (6.7% of the total) and a reproducible thickness. This may have advantages over manual preparation techniques.

Deep Lamellar Endothelial Keratoplasty: Visual Acuity, Astigmatism, and Endothelial Survival in a Large Prospective Series

To report the 6-month results for the treatment of endothelial dysfunction in a large, prospective series of deep lamellar endothelial keratoplasty (DLEK) procedures. Prospective, noncomparative, interventional case series. One hundred eyes of 88 patients with corneal edema from Fuchs' dystrophy and pseudophakia. A limbal, scleral, partial-depth incision provided access for a deep lamellar corneal pocket dissection. Two eyes were converted to penetrating keratoplasty (PK) at the time of DLEK surgery because of poor dissections. Of the 98 eyes that had completed DLEK surgeries, 36 eyes received a large-incision technique (9-mm scleral access incision) and 62 eyes received a small-incision technique (5-mm scleral access incision). A 7.5- to 8.0-mm posterior lamellar disc of recipient tissue then was excised and replaced through the pocket with a similar size donor disc containing healthy endothelium. A temporary air bubble in the anterior chamber was used for donor tissue adherence, and no surface corneal incisions or sutures were necessary. Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction (MR) astigmatism, and endothelial cell density (ECD) were evaluated prospectively. At 6 months after surgery, all 98 DLEK corneas were clear and the grafts were healed in good position. The mean BSCVA was 20/46, with a range between 20/20 and 20/400. The average MR astigmatism was 1.34+/-0.86 diopters (D), representing an average change in astigmatism from before surgery of +0.28+/-1.08 D (P = 0.013). The average ECD at 6 months was 2140+/-427 cells/mm2, representing a mean cell loss from preoperative donor cell measurements of 25%. The DLEK procedure, with its absence of corneal surface incisions and sutures, preserves the normal corneal topography, minimizes astigmatism, and provides a healthy donor endothelial cell count and function. The DLEK procedure represents a reasonable alternative to PK, and compared with historical PK data, offers superior refractive outcomes in the treatment of endothelial dysfunction.

Deep Lamellar Endothelial Keratoplasty: Surgery in Complex Cases With Severe Preoperative Visual Loss

This study was designed to report the use of deep lamellar endothelial keratoplasty (DLEK) in combination with other intraocular surgeries in the treatment of eyes with severe bullous keratopathy and visual loss. DLEK surgery was performed in six patients with severe bullous keratopathy and preoperative vision with a range of between count fingers and light perception only. DLEK was combined with vitrectomy and placement of a ciliary sulcus sutured intraocular lens in four patients and with cataract surgery in one patient. Two patients with vitreoretinal disease underwent pars plana vitrectomy within only 4 months after the DLEK donor tissue had been placed. Graft clarity, Snellen visual acuities, refractive astigmatism, endothelial cell counts, and corneal topography were prospectively measured at 6 and 12 months postoperatively. At 6 months after DLEK surgery, all grafts were clear and vision improved in all patients. Best spectacle-corrected visual acuity improved from count fingers level (or worse) before surgery to a range of 20/40 to 20/200 after surgery. Average refractive astigmatism at 6 months was 2.0 diopters (range, 0.50-4.00 diopters). The average postoperative endothelial cell count was 1,679 +/- 380 (range, 1,200-2,298) cells/mm at 6 months and 1,449 +/- 365 (range, 1,105-2,043) cells/mm at 12 months. Vitreoretinal surgery subsequent to graft placement did not affect corneal clarity or dislodge the grafted tissue. DLEK surgery can be used in cases with severe visual loss caused by bullous keratopathy with transfer of healthy donor endothelium, clearing of the central cornea, and restoration of useful vision. DLEK also can be successfully combined with other intraocular surgeries such as vitrectomy, intraocular lens exchange, and sutured intraocular lens surgery. The DLEK graft can tolerate subsequent intraocular surgery performed as early as 3 months after placement of the donor tissue.

A Practical Femtosecond Laser Procedure for DLEK Endothelial Transplantation

The manual dissection technique for deep lamellar endothelial keratoplasty (DLEK) surgery is technically difficult and may not be smooth enough for consistently optimal postoperative vision. We evaluated the feasibility and efficacy of using a femtosecond laser to perform the dissections in the DLEK procedure. The Intralase femtosecond laser (with standard LASIK surgery spot settings) was used to create a 9.4-mm wide, 400-microm deep lamellar pocket dissection and a 5.0-mm wide side cut near-exit incision in 10 "recipient" whole cadaver eyes and in 10 "donor" cadaver corneal-scleral caps mounted onto an artificial anterior chamber. Recipient and donor disks were resected with special scissors, and the donor tissue was transplanted using the small incision (5.0-mm) DLEK technique. Topography of the recipient eyes was measured pre- and postlaser dissection, and the recipient and donor tissues were sent for scanning electron microscopy (SEM) analysis of the smoothness of the dissections. Successful lamellar dissections were obtained in all tissues. The mean recipient topographic corneal curvature postoperatively was 43.3 +/- 1.7 diopters, which was not a significant change from the preoperative curvature of 44.0 +/- 0.8 diopters (P = 0.430). The mean recipient topographic astigmatism postoperatively was 1.7 +/- 0.8 diopters, which was not a significant change from the preoperative recipient astigmatism of 1.6 +/- 0.7 diopters (P = 0.426). Comparison of the histology of the laser-formed stromal dissections by scanning electron microscopy, however, did not appear significantly better than histology after manual DLEK dissections in either the recipient or the donor tissues. A femtosecond laser can create the lamellar dissections for the DLEK procedure, making this procedure easier and faster. As in the manual technique, corneal topography is unchanged by this surgery. More work will need to be done, however, to optimize the laser settings to provide even smoother interface surfaces.

Table of Content 1

To report the 6- and 12-month results of the first United States clinical series of deep lamellar endothelial keratoplasty (DLEK) in the treatment of endothelial dysfunction.Prospective, noncomparative, interventional case series.Eight eyes of eight patients with corneal edema from Fuchs’ dystrophy and pseudophakia.A 9.0-mm limbal, scleral, partial-depth incision provided access for a deep lamellar corneal pocket dissection. A 7.5- to 8.0-mm posterior lamellar disc of recipient tissue was then excised and replaced through the pocket with a same size donor disc containing healthy endothelium. A temporary air bubble in the anterior chamber was used for donor tissue adherence, and no surface corneal incisions or sutures were necessary.Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction astigmatism, TMS-1 topography, ultrasonic pachymetry, Orbscan topography, and endothelial cell density were evaluated. Intraoperative and postoperative complications are reported.At 6 and 12 months after surgery, all eight corneas were clear and the grafts were healed in good position. At 6 months, the BSCVA varied between 20/30 and 20/70, the average change in astigmatism from before surgery was +1.13 diopters (D; ±1.50 D), the average change in corneal power was −0.4 D (±1.7 D), the average pachymetry was 648 μm (±134 μm), and the average endothelial cell count was 2290 cells/mm2 (±372 cells/mm2). At 12 months, three of the four eyes reaching this time gate were 20/40 or better, with a change in astigmatism from before surgery of only +0.81 D (± 0.55 D), a corneal power change of −1.3 D (± 0.4 D), and an endothelial density of 2409 cells/mm2 (± 154 cells/mm2). One of the original nine eyes entered into this study required conversion to standard penetrating keratoplasty as a result of a microperforation during recipient pocket dissection and has experienced no ill effects.The DLEK procedure, with its absence of corneal surface incisions and sutures, is a safe procedure that preserves the normal corneal topography, minimizes astigmatism and corneal power changes, and provides a healthy donor endothelial cell count and function. If interface optical clarity can be maintained, then this technique offers considerable advantages over penetrating keratoplasty in the treatment of endothelial dysfunction.

Penetrating Keratoplasty, Deep Lamellar Endothelial Keratoplasty, and Posterior Lamellar Keratoplasty in the Horse

Corneal transplantation is a viable and successful surgical technique in the horse. Full thickness penetrating keratoplasty (PK) may be performed for melting ulcers, iris prolapse/descemetoceles, and full thickness stromal abscesses (SA). Deep lamellar endothelial keratoplasty (DLEK) and posterior lamellar keratoplasty (PLK) are split thickness penetrating keratoplasties utilized for deep stromal abscesses (DSA) with clear overlying anterior stroma. Frozen donor grafts can be used successfully for transplants in the horse eye. Corneal transplants in horses are associated with high success rates, good visual outcomes (>80%), and shorter treatment times than medical treatment alone of these eye problems alone, but the corneal transplants in horses do vascularize, have some degree of opacity, and thus exhibit some degree of graft rejection.

Small-Incision Deep Lamellar Endothelial Keratoplasty (DLEK)

To evaluate the visual, topographic, and endothelial survival results in 25 consecutive patients who have received small-incision deep lamellar endothelial keratoplasty (DLEK) transplant surgery. DLEK surgery was performed in 25 patients with Fuchs endothelial dystrophy or pseudophakic bullous keratopathy utilizing a 5-mm scleral access incision. Snellen visual acuities, refractive astigmatism, endothelial cell counts, and corneal topography were prospectively measured at preop and at 6 months after small-incision DLEK endothelial replacement surgery. Best spectacle-corrected visual acuity improved from an average of 20/90 (range 20/25 to 2'/200) before surgery to an average of 20/44 (range 20/25 to 20/200, P < 0.001) 6 months after surgery, with 56% of patients 20/40 or better at 6 months. Average refractive astigmatism at 6 months was 1.31 +/- 0.59 diopters (range 0.25 to 2.50 diopters), representing an average increase in astigmatism of 0.45 diopters from preop. Despite folding of the donor graft for placement into the recipient posterior lamellar bed, the average postoperative endothelial cell count at 6 months was 2122 +/- 510 cells/mm2 (range 1097 to 3202 cells/mm2) or an average 24% cell loss from donor eye preop measurements, a level of cell loss comparable to that reported after PK or after large-incision DLEK surgery. Small-incision DLEK surgery preserves the recipient corneal topography, resulting in very little change in astigmatism from preop. The excellent postoperative donor endothelial cell counts attest to the survival of donor endothelium despite folding of the graft for insertion. The small-incision DLEK technique may become the standard for endothelial replacement surgery in the future.