A surgical technique for posterior lamellar keratoplasty

In vivo laser confocal microscopy after Descemet's membrane endothelial keratoplasty

OBJECTIVE

To investigate the in vivo corneal changes in patients with bullous keratopathy who underwent Descemet's membrane endothelial keratoplasty (DMEK) with the use of in vivo laser confocal microscopy.

DESIGN

Single-center, retrospective clinical study.

PARTICIPANTS

Five eyes of 4 patients (3 men, 1 women; mean age, 61.3 ± 9.6 years) with bullous keratopathy who had undergone successful DMEK were enrolled in this study.

TESTING

In vivo laser confocal microscopy was performed before and 1, 3, and 6 months after DMEK.

MAIN OUTCOME MEASURES

Selected confocal images of corneal layers were evaluated qualitatively and quantitatively for the degree of haze and the density of deposits. Subepithelial haze, donor-recipient interface haze, donor-recipient interface particles, and host stromal needle-shaped materials were graded on a scale of 4 categories (grade 0 = none, grade 1 = mild, grade 2 = moderate, grade 3 = severe) at each time point. Time trends of the outcomes were graphically displayed and evaluated with Mantel-Haenszel trend test.

RESULTS

The following were observed preoperatively in all patients: slight corneal epithelial edema, moderate subepithelial haze, keratocytes in a honeycomb pattern, and tiny needle-shaped materials in the stroma. After DMEK, moderate subepithelial haze persisted during the follow-up period. Needle-shaped materials had a tendency to decrease after DMEK. Most notably, donor-recipient interface haze and donor-recipient interface particles were barely noticeable after DMEK as early as 1 month postoperatively.

CONCLUSIONS

In vivo laser confocal microscopy can identify subclinical corneal abnormalities after DMEK, such as subepithelial haze, host stromal needle-shaped materials, and minimum donor-recipient interface haze/particles. These abnormalities seemed subtle compared with Descemet stripping automated endothelial keratoplasty; this may explain the superior postoperative visual acuity after DMEK. Further studies with this technology in a large number of patients and long-term follow-up are needed to fully understand the long-term corneal changes after DMEK.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Quality of vision in eyes after selective lamellar keratoplasty

With the increasing popularity of selective lamellar keratoplasty procedures, it is important to characterize the optical differences among penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK). The impact of optical differences on the visual acuity (VA) in eyes after keratoplasty is significant. Quantitative evaluation of corneal higher-order aberrations (HOAs) of anterior and posterior surfaces using a rotating Scheimpflug-based corneal topographer, showed that eyes that undergo DSAEK have lower anterior corneal HOAs compared with eyes subjected to PK or DALK. In DSAEK, the anterior corneal surfaces are not replaced, which is in contrast to PK or DALK, where they are replaced. Through evaluation of corneal scatter with a densitometry program associated with the rotating Scheimpflug-based corneal topographer, 3 characteristic patterns of corneal scatter were found in eyes that had undergone keratoplasty. Investigation of the impact of corneal HOAs and corneal scatter on VA after keratoplasty showed that the VA was correlated significantly with corneal scatter.

Comparative cost-effectiveness analysis of descemet stripping automated endothelial keratoplasty versus penetrating keratoplasty in the United States

PURPOSE

To perform a comparative cost-effectiveness analysis of Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK) for corneal endothelial disease.

DESIGN

Retrospective cost-effectiveness analysis.

METHODS

This cost-effectiveness analysis was performed from a third-party payer perspective with a 5-year time horizon. Probabilities of outcomes and complications of each of the procedures were calculated based on review of the published literature. A model was constructed to compare the costs and utilities associated with DSAEK and PK. Costs of donor tissue preparation, surgery, follow-up, postoperative complications, and procedures were considered. Utility values were based on quality-adjusted life years associated with visual acuity outcomes. Both costs and utilities were discounted at 3% per year. Sensitivity analyses were performed on key model inputs.

RESULTS

Base case analysis found DSAEK to be less costly compared with PK ($9362 vs $10 239), with greater utility (3.15 vs 2.47 quality-adjusted life years). Sensitivity analyses revealed that even at graft failure rates for DSAEK approaching the rates for PK, DSAEK would still reduce costs. Varying the dislocation rate in our model showed that even at dislocation rates approaching 50%, DSAEK remained less costly. Further, with DSAEK rejection rates as high as 28%, DSAEK would remain a dominant procedure over PK.

CONCLUSIONS

Comparative cost-effectiveness analysis of DSAEK versus PK indicates favorable cost and utility outcomes associated with DSAEK for treatment of corneal endothelial disease. Longer follow-up of DSAEK outcomes will provide more accurate information regarding long-term cost-effectiveness of the procedure.

Intraocular pressure after descemet stripping endothelial keratoplasty (DSEK)

To assess the incidence of elevated intraocular pressure (IOP) after descemet stripping endothelial keratoplasty (DSEK). Retrospective case series. From the start of the technique in our hospital in 2003 until the middle of 2010, 73 eyes underwent DSEK, of which 66 (90.5 %) had a clear graft 1 year after surgery. IOP data pre- and postoperatively were analyzed. Follow-up was 1-5 years (mean 3.8, SD 1.3). Mean age was 71 years (SD 11, range 43-89). Three eyes (4.5 %) had a history of glaucoma before DSEK. Mean pre-operative IOP was 12.4 mmHg (SD ± 4.3). Mean IOP 1 day post-operatively was 16.4 mmHg (±9.2). Mean IOP after 1 and 6 months, and 1, 3, and 5 years were, respectively, 13.9 (±5.3), 14.7 (±5.6), 14.2 (±5.4), 13.8 (±3.7), and 12.6 (±3.5). Seventeen percent (11 eyes) had a postoperative rise in IOP which needed medical or surgical intervention: 8 % (5 eyes) had a rise in IOP 1 day after DSEK, of which 1 underwent a trabeculectomy 7 months after DSEK surgery; 6 % (4 eyes) had a rise in IOP later in the postoperative period, which could all be managed medically; and 3 % (2 eyes) had increased IOP 1 day after DSEK and later in the postoperative period, both eyes underwent a trabeculectomy 5 and 24 months, respectively, after DSEK surgery. An increase in IOP was encountered in 17 % of DSEK patients. Checking the IOP in the short and long postoperative period is necessary.

Indications of optical coherence tomography in keratoplasties: literature review

Optical coherence tomography (OCT) of the anterior segment, in particular corneal OCT, has become a reliable tool for the cornea specialist, as it provides the acquisition of digital images at high resolution with a noncontact technology. In penetrating or lamellar keratoplasties, OCT can be used to assess central corneal thickness and pachymetry maps, as well as precise measurements of deep stromal opacities, thereby guiding the surgeon to choose the best treatment option. OCT has also been used to evaluate the keratoplasty postoperative period, for early identification of possible complications, such as secondary glaucoma or donor disc detachments in endothelial keratoplasties. Intraoperatively, OCT can be used to assess stromal bed regularity and transparency in anterior lamellar surgeries, especially for those techniques in which a bare Descemet's membrane is the goal. The purpose of this paper is to review and discuss the role of OCT as a diagnostic tool in various types of keratoplasties.

Comparison of the Surgical Outcomes of Various Methods of Endothelial Keratoplasty

PURPOSE

The objective of this study was to evaluate the outcomes of various techniques of endothelial keratoplasty (EK) including deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), and Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

This was a retrospective comparative case series.

METHODS

The medical records of 48 consecutive patients who have undergone EK in a tertiary eye center between January 2005 and June 2011 were reviewed. Information related to demographics, visual acuity, corneal endothelial cell count, and postoperative complications was recorded.

RESULTS

The series included 11 eyes with DLEK, 11 eyes with DSEK, and 26 eyes with DSAEK. There was no significant difference in visual outcomes, endothelial cell loss, and postoperative complications between the 3 groups 1 year after surgery. The mean logMAR visual acuity at 12 months was 0.54 (SD, 0.26) for DLEK, 0.55 (SD, 0.47) for DSEK, and 0.63 (SD, 0.48) for DSAEK, respectively. The 6-month endothelial cell density loss was 48.4%, 39.2%, and 47.5% for the DLEK, DSEK, and DSAEK groups, respectively. Early postoperative graft dislocation occurred in 1 (9%) of the DLEK cases, 2 (18%) of the DSEK cases, and 1 (4%) of the DSAEK cases. All of these cases were successfully repositioned.

CONCLUSIONS

Despite the various evolution and surgical modifications and development in EK in the past few years, the visual outcomes and postoperative complications between DLEK, DSEK, and DSAEK were comparable.

[Reproducibility of femtosecond laser incisions for posterior lamellar keratoplasty in vitro]

PURPOSE

In the last decade surgeons have tried to use posterior lamellar keratoplasty (PLAK) in a way that maintains the biomechanical stability of the intact cornea. Femtosecond lasers can be used to cut a lenticle out of the posterior part of the stroma. The purpose of this study was to assess the reproducibility of the generated lenticles.

METHODS

The FEMTEC-Laser (20/10 Perfect Vision, Heidelberg, Germany) was used to perform posterior lamellar dissections. The goal was to assess the real thickness of the graft in comparison to the intended thickness predefined with the laser. The histological preparations were viewed using light microscopy (Olympus microscope). Main outcome measures included difference of intended versus real distance of the horizontal plane from Bowman's layer and quantification of the created bubbles.

RESULTS

The intended distance was reached with a precision of 115-160 µm and was constant over the whole length of the lenticle depending on the depth of the laser action. The number and size of the generated bubbles was equal in the different layers. At least one zone of stromal condensation could be found in 88.9% of the corneas and 63% of the corneas showed a partial perforation or minimal lesions of Descemet's membrane. The distance of the two closest bubbles to Descemet's membrane increased in thinner lenticles, i.e. a greater distance from Bowman's layer. No damage occurred due to compression or heat.

CONCLUSIONS

As the laser generates a reproducible number of bubbles of the same size, precise incisions can be achieved. Thus the femtosecond laser proved to be an accurate tool for PLAK. In the majority of cases a lesion of Descemet's membrane could be found which seems to make the removal of the lenticles easier. A disadvantage is a decreasing probability of a lesion of Descemet's membrane as well as the decreasing precision in thinner lenticles.

No-Touch Technique and a New Donor Adjuster for Descemet's Stripping Automated Endothelial Keratoplasty

Purpose

One difficulty with Descemet's stripping automated endothelial keratoplasty (DSAEK) is air management during surgery and donor endothelial lamella centering. We evaluated the no-touch technique for donor centering and the use of a newly developed DSAEK donor adjuster.

Methods

We evaluated the records of 12 consecutive patients (mean age 75.3 years) with bullous keratopathy who had undergone DSAEK. In all cases, the no-touch technique was attempted first. When the no-touch technique failed, a DSAEK donor adjuster with a 30-gauge cannula resembling a curved reverse Sinskey hook was used for donor centering. The adjuster allows air injection during donor centering.

Results

The no-touch technique using simple corneal surface massage to center the graft was successful in 4 cases (33.3%), while 4 cases required ocular tilting (33.3%) in addition to corneal surface massage. The no-touch technique was ineffective in 4 cases (33.3%), but the donor adjuster was used successfully and easily for these patients. Comparing the endothelial cell loss rate between the no-touch technique group and the donor adjuster group, there was no significant difference at 6 months.

Conclusions

The no-touch technique was useful for better control of DSAEK donor centering in most cases. When the no-touch technique was ineffective, the DSAEK donor adjuster was uniformly successful.

Evaluation of interface quality in organ-cultured lamellar corneal transplants

BACKGROUND

With increasing numbers of lamellar keratoplasties, eye banks are challenged to deliver precut lamellar donor tissue. In Europe, the most common technique of corneal storage is organ culture which requires a deswelling process before surgical processing. The aim of this study was to investigate the influence of different deswelling times on the cutting plane quality after microkeratome-assisted lamellar dissection.

METHODS

Eight paired donor corneas (16 specimens) not suitable for transplantation were organ cultured under standard conditions at the Eye Bank of the Ludwig-Maximilians Universität, Munich, Germany. Pairs of corneal buttons were analyzed during the deswelling process in dextrane-containing medium. While one cornea was cut at an early time point during the deswelling process and put back into deswelling medium thereafter, the partner cornea was completely deswollen and dissected after 72 hours. Specimens were then further processed for scanning electron microscopy. Surface quality was assessed both digitally using Scanning Probe Imaging Processing software, and manually by three blinded graders.

RESULTS

The corneal buttons processed at the beginning of the deswelling process had a smoother surface when compared to the partner cornea that was cut at the end of the deswelling process. In our setting, no relevant difference was detectable between manual and automated microkeratome dissection.

CONCLUSION

For lamellar keratoplasty, organ-cultured corneas should be processed at an early stage during the deswelling process. We interpret the smoother dissection plane during early deswelling as a result of mechanical properties in a highly hydrated cornea.

Endothelial quality of pre-cut posterior corneal lamellae for Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S): two-year outcome of manual preparation in an ocular tissue bank

To assess the quantitative and qualitative parameters of pre-cut posterior corneal lamellae for Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S) prepared manually in the Ocular Tissue Bank Prague. All 65 successfully prepared pre-cut posterior corneal lamellae provided for grafting during a 2-year period were analyzed retrospectively. The lamellae, consisting of a central zone of endothelium-Descemet membrane surrounded by a supporting peripheral stromal rim, were prepared manually from corneoscleral buttons having an endothelial cell density higher than 2,500 cells/mm(2). The live endothelial cell density, the percentage of dead cells, the hexagonality and the coefficient of variation were assessed before and immediately after preparation as well as after 2 days of organ culture storage at 31 °C. Altogether, the endothelium of 57 lamellae was assessed. Immediately after preparation, the mean live endothelial cell density was 2,835 cells/mm(2) and, on average, 1.8 % of dead cells were found. After 2 days of storage, the cell density decreased significantly to 2,757 cells/mm(2) and the percentage of dead cells to 1.0 %. There was a significant change in the mean hexagonality and the coefficient of variation after lamellar preparation and subsequent storage. The amount of tissue wasted during the preparation was 23 %. The endothelial cell density of posterior corneal lamellae sent for DMEK-S was higher than 2,700 cells/mm(2) in average with a low percentage of dead cells; 65 pre-cut tissues were used for grafting during a 2-year period.

Corneal donor tissue preparation for endothelial keratoplasty

Over the past ten years, corneal transplantation surgical techniques have undergone revolutionary changes^1,2. Since its inception, traditional full thickness corneal transplantation has been the treatment to restore sight in those limited by corneal disease. Some disadvantages to this approach include a high degree of post-operative astigmatism, lack of predictable refractive outcome, and disturbance to the ocular surface. The development of Descemet's stripping endothelial keratoplasty (DSEK), transplanting only the posterior corneal stroma, Descemet's membrane, and endothelium, has dramatically changed treatment of corneal endothelial disease. DSEK is performed through a smaller incision; this technique avoids 'open sky' surgery with its risk of hemorrhage or expulsion, decreases the incidence of postoperative wound dehiscence, reduces unpredictable refractive outcomes, and may decrease the rate of transplant rejection^3-6.

Initially, cornea donor posterior lamellar dissection for DSEK was performed manually¹ resulting in variable graft thickness and damage to the delicate corneal endothelial tissue during tissue processing. Automated lamellar dissection (Descemet's stripping automated endothelial keratoplasty, DSAEK) was developed to address these issues. Automated dissection utilizes the same technology as LASIK corneal flap creation with a mechanical microkeratome blade that helps to create uniform and thin tissue grafts for DSAEK surgery with minimal corneal endothelial cell loss in tissue processing.

Eye banks have been providing full thickness corneas for surgical transplantation for many years. In 2006, eye banks began to develop methodologies for supplying precut corneal tissue for endothelial keratoplasty. With the input of corneal surgeons, eye banks have developed thorough protocols to safely and effectively prepare posterior lamellar tissue for DSAEK surgery. This can be performed preoperatively at the eye bank. Research shows no significant difference in terms of the quality of the tissue⁷ or patient outcomes^8,9 using eye bank precut tissue versus surgeon-prepared tissue for DSAEK surgery. For most corneal surgeons, the availability of precut DSAEK corneal tissue saves time and money¹⁰, and reduces the stress of performing the donor corneal dissection in the operating room. In part because of the ability of the eye banks to provide high quality posterior lamellar corneal in a timely manner, DSAEK has become the standard of care for surgical management of corneal endothelial disease.

The procedure that we are describing is the preparation of the posterior lamellar cornea at the eye bank for transplantation in DSAEK surgery (Figure 1).

Endothelial keratoplasty: a revolution in evolution

Endothelial keratoplasty (EK) is continually evolving both in surgical technique and clinical outcomes. Descemet's stripping endothelial keratoplasty (DSEK) has replaced penetrating keratoplasty (PK) as the treatment of choice for corneal endothelial dysfunction. It is safe and predictable and offers early visual rehabilitation. Newer iterations include Descemet's membrane endothelial keratoplasty, Descemet's membrane automated endothelial keratoplasty, and other hybrid techniques. Early data on these newer EK techniques suggests that they provide significantly better visual outcomes compared to DSEK. Initial 5-year survival data indicates that EK is at least comparable to PK, and more widespread survival data is anticipated. Further work is needed to simultaneously optimize visual outcomes, refractive predictability, and endothelial cell survival, as well as surgical techniques of donor preparation and insertion.

Descemet membrane endothelial keratoplasty versus descemet stripping automated endothelial keratoplasty

PURPOSE

To evaluate visual outcome and endothelial cell survival after Descemet membrane endothelial keratoplasty (DMEK) in comparison with Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

Single-center, retrospective, consecutive case series.

METHODS

Thirty-eight eyes of 38 consecutive patients undergoing DMEK, who completed a 6-month follow-up, were compared with 35 eyes of 35 consecutive patients undergoing DSAEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy. Main outcome measures included best-corrected visual acuity (in logarithm of the minimal angle of resolution [logMAR] units) and endothelial cell density within a 6-month follow-up.

RESULTS

Best-corrected visual acuity increased from 0.70 ± 0.48 logMAR and 0.75 ± 0.32 logMAR before surgery to 0.21 ± 0.14 logMAR and 0.48 ± 0.19 logMAR 3 months after DMEK and DSAEK (P < .001), respectively, and to 0.17 ± 0.12 logMAR and 0.36 ± 0.15 logMAR 6 months after DMEK and DSAEK (P < .001), respectively. Endothelial cell density decreased from 2575 ± 260 cells/mm(2) and 2502 ± 220 cells/mm(2) before surgery to 1498 ± 244 cells/mm(2) and 1778 ± 420 cells/mm(2) 3 months after DMEK and DSAEK (P < .001), respectively, and to 1520 ± 299 cells/mm(2) and 1532 ± 495 cells/mm(2) 6 months after DMEK and DSAEK (P = .483), respectively. Central corneal thickness decreased from 652 ± 92 μm before surgery to 517 ± 45 μm 6 months after DMEK, and from 698 ± 137 μm before surgery to 618 ± 66 μm 6 months after DSAEK.

CONCLUSIONS

DMEK provided faster and more complete visual rehabilitation when compared with DSAEK. However, there were no significant differences concerning endothelial cell survival within a 6-month follow-up.

Effect of fibrin glue on the biomechanical properties of human Descemet's membrane

Background

Corneal transplantation has rapidly evolved from full-thickness penetrating keratoplasty (PK) to selective tissue corneal transplantation, where only the diseased portions of the patient's corneal tissue are replaced with healthy donor tissue. Descemet's membrane endothelial keratoplasty (DMEK) performed in patients with corneal endothelial dysfunction is one such example where only a single layer of endothelial cells with its basement membrane (10–15 µm in thickness), Descemet's membrane (DM) is replaced. It is challenging to replace this membrane due to its intrinsic property to roll in an aqueous environment. The main objective of this study was to determine the effects of fibrin glue (FG) on the biomechanical properties of DM using atomic force microscopy (AFM) and relates these properties to membrane folding propensity.

Methodology/Principal Findings

Fibrin glue was sprayed using the EasySpray applicator system, and the biomechanical properties of human DM were determined by AFM. We studied the changes in the “rolling up” tendency of DM by examining the changes in the elasticity and flexural rigidity after the application of FG. Surface topography was assessed using scanning electron microscopy (SEM) and AFM imaging. Treatment with FG not only stabilized and stiffened DM but also led to a significant increase in hysteresis of the glue-treated membrane. In addition, flexural or bending rigidity values also increased in FG-treated membranes.

Conclusions/Significance

Our results suggest that fibrin glue provides rigidity to the DM/endothelial cell complex that may aid in subsequent manipulation by maintaining tissue integrity.

Keratoplasty for corneal endothelial disease, 2001-2009

PURPOSE

To determine the rates of keratoplasty for corneal endothelial disease (CED) from 2001 to 2009 in a large managed care network in the United States, factors that affect which patients undergo this procedure and surgical outcomes.

DESIGN

A retrospective review of data from a longitudinal cohort study.

PARTICIPANTS

Beneficiaries with CED aged ≥ 40 years who were receiving eye care during 2001 to 2009.

METHODS

Rates of keratoplasty for CED were determined at 6-month intervals from January 2001 to December 2009. The mean number of postoperative visits and rates of severe adverse events in the year after keratoplasty surgery were monitored over the course of the decade. Univariable and multivariable logistic regression were performed to identify sociodemographic and other factors associated with undergoing keratoplasty for CED.

MAIN OUTCOME MEASURES

Odds of undergoing keratoplasty with 95% confidence intervals, changes in the number of postoperative visits, and rates of adverse events in the year after keratoplasty.

RESULTS

Of the 38 648 enrollees who met the inclusion criteria, 2187 underwent ≥ 1 keratoplasty surgeries from January 2001 to December 2009. After adjustment for confounding factors, individuals with CED had 47% increased odds of undergoing keratoplasty during 2007-2009 relative to 2001-2006. The mean number of postoperative visits to eyecare providers in the year after keratoplasty declined from 12.6 in 2001-2006 to 10.5 in 2007-2008. There was no difference in the proportion of enrollees who developed adverse events after keratoplasty over time.

CONCLUSIONS

In this analysis of claims data, from 2001 to 2009, a period during which there was an increase in the rate of endothelial keratoplasty, we observed a trend of greater rates of keratoplasty in patients with CED and fewer visits for postoperative care in the later years of the decade compared with the earlier years, along with no change in rates of severe adverse events.

Irregularity of the posterior corneal surface during applanation using a curved femtosecond laser interface and microkeratome cutting head

PURPOSE

To evaluate the irregularity of the posterior corneal surface and intrastromal dissection during the preparation of donor tissue for Descemet stripping automated endothelial keratoplasty (DSAEK) using a curved interface femtosecond laser and microkeratome.

METHODS

Sixteen human donor corneas unsuitable for transplantation were divided into two groups: a femtosecond (FS) laser group (n=7) using the VisuMax femtosecond laser (Carl Zeiss Meditec) and a microkeratome group (n=9) using the Amadeus II microkeratome (Ziemer Ophthalmic Group). The corneas were fixed on artificial anterior chambers. Horizontal cross-sections were obtained using spectral-domain optical coherence tomography prior to applanation, during applanation, as well as during and after intrastromal dissection at 450-μm corneal depth. The posterior surface and the dissection line were evaluated for irregularity by fitting a second-order polynomial curve using regression analysis and obtaining the root-mean-square error (RMSE). Groups were compared using analysis of variance.

RESULTS

The RMSE of the posterior surface prior to applanation was 9.7 ± 3.1 μm in the FS laser group and 10.2 ± 2.3 μm in the microkeratome group. The RMSE increased to 50.7 ± 9.4 μm and 20.9 ± 6.1 μm during applanation and decreased again to 10.6 ± 1.4 μm and 8.1 ± 1.8 μm after applanation in the FS laser and microkeratome groups, respectively. The RMSE of the intrastromal cut was 19.5 ± 5.7 μm in the FS laser group and 7.7 ± 3.0 μm in the microkeratome group (P<.001).

CONCLUSIONS

Our results show significantly greater irregularity with the curved interface femtosecond laser-assisted cleavage compared to microkeratome-assisted corneal dissection, possibly due to applanation-derived deformation of the posterior cornea.

Descemet stripping automated endothelial keratoplasty using infant donor tissue

PURPOSE

The purpose of this study was to report the outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) surgery using infant (2 years and younger) donor tissue.

METHODS

Retrospective interventional case series of 3 patients.

RESULTS

All 3 patients in this series had good visual outcomes and clear DSAEK grafts. The average endothelial cell count (ECC) from infant donors was very high (4239 cells/mm(2)). Similarly, the average postoperative ECC was also high (3359 cells/mm(2)) with a mean endothelial cell loss of 20.9% at 11-month follow-up. One patient remarkably had an ECC of 4065 cells per square millimeter at 1-year follow-up with a net endothelial cell loss of only 13.3%. No difficulties were noted using infant donor tissue, including the intraoperative use of the Moria microkeratome to prepare the DSAEK donor, insertion of the donor graft, or with air-bubble management.

CONCLUSIONS

Using infant donor tissue for DSAEK surgery is safe and may be preferable, particularly for younger patients. The higher preoperative endothelial cell densities in infant donor tissue should improve graft survival and long-term maintenance of corneal transparency provided that surgery-related endothelial cell loss is minimized.

Characteristic higher-order aberrations of the anterior and posterior corneal surfaces in 3 corneal transplantation techniques

PURPOSE

To investigate the corneal higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

Retrospective, case-control study.

METHODS

study population: Twenty-four eyes underwent PK, 28 eyes underwent DALK, and 19 eyes underwent DSAEK; 29 normal eyes served as controls. observation procedures: The anterior and posterior corneal heights and pachymetric data were obtained with a Scheimpflug-based corneal topographer. Corneal HOAs for 4-mm pupils were calculated from the height data and were expanded with normalized Zernike polynomials. The HOAs resulting from the anterior and posterior corneal surfaces were compared among the procedures. main outcome measures: Anterior and posterior corneal HOAs (root mean square).

RESULTS

Control eyes had significantly lower total HOAs and Zernike vector terms of the anterior and posterior surfaces than the other groups, except for spherical aberration. The mean anterior corneal surface total HOAs in the PK, DALK, DSAEK, and control groups were 1.38 ± 0.67 μm, 1.19 ± 0.57 μm, 0.61 ± 0.33 μm, and 0.21 ± 0.07 μm, respectively. The anterior corneal HOAs in the DSAEK group were significantly less than those in the PK group (P < .001) and DALK group (P < .001). The mean posterior corneal surface total HOAs were, respectively, 0.20 ± 0.09 μm, 0.24 ± 0.11 μm, 0.27 ± 0.15 μm, and 0.07 ± 0.02 μm. There were no significant differences in the posterior corneal HOAs among the treatment groups.

CONCLUSIONS

Because the refractive indices between the anterior and the posterior surfaces differed greatly, eyes that undergo DSAEK have lower anterior corneal HOAs compared with PK or DALK eyes. However, the anterior and posterior corneal HOAs in DSAEK eyes still were greater than those in control eyes.

Incidence of early allograft rejection after Descemet membrane endothelial keratoplasty

PURPOSE

To report the incidence of early allograft rejection after Descemet membrane endothelial keratoplasty (DMEK), that is, transplantation of isolated Descemet membrane with its endothelium.

METHODS

The first series of 120 eyes of 105 patients operated on for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy, with an average 2 years of follow-up after 9.0- to 10.0-mm-diameter DMEK, enrolled in our study.

RESULTS

During the entire study period, only 1 of the eyes showed any signs of a cellular immune response to the Descemet graft. A 76-year-old patient presented with discomfort, reduced visual acuity to counting fingers, corneal decompensation, and a Khodadoust line in the central cornea 4 months after (decentered) DMEK. Intensified topical corticoid therapy resulted in a complete visual recovery to 20/25 (0.8) within weeks.

CONCLUSIONS

A "classic" allograft rejection (with an appearance similar to that after penetrating keratoplasty) can occur after DMEK. However, compared with the earlier (endothelial) keratoplasty procedures, DMEK may be associated with a lower rejection rate of ≤ 1%, despite transplant diameters of ± 9.5 mm. The apparent immune tolerance in DMEK may result from either less "upregulation" or more "downregulation" of the immune system.

Endothelial keratoplasty: fellow eyes comparison of Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty

PURPOSE

To evaluate patients' perspectives and outcomes of 2 different endothelial keratoplasty (EK) techniques performed in the fellow eyes of the same patients: Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK).

METHODS

In this fellow eye, comparative, retrospective case series, the records of 15 patients who underwent DSAEK in 1 eye and DMEK in the fellow eye and completed at least 1 year of follow-up after the second procedure were reviewed. Visual outcomes and endothelial cell density were assessed. Patient satisfaction was evaluated using a subjective questionnaire.

RESULTS

At 12 months postoperatively, the mean best spectacle-corrected visual acuity (BSCVA) in the DMEK group was 0.07 logarithm of the minimum angle of resolution (20/24) and 0.20 logMAR (20/32) in the DSAEK group (P = 0.004). The majority of the patients (85%) perceived better visual quality in the DMEK eye. Furthermore, 62% preferred or would recommend DMEK to a friend or relative, whereas 15% preferred DSAEK and 23% reported no preference between the surgical procedures. The 1-year endothelial cell loss and the perceived discomfort level during the postoperative period were comparable for the 2 procedures.

CONCLUSIONS

The majority of the patients preferred or would recommend the DMEK procedure. Faster visual recovery and better final visual acuity were the main benefits of the DMEK technique.

A prospective study comparing EndoGlide and Busin glide insertion techniques in descemet stripping endothelial keratoplasty

PURPOSE

To compare a new insertion method using an EndoGlide (Angiotech/Network Medical Products) with the standard Busin glide (Moria USA) assisted insertion of the posterior lamellar corneal graft in Descemet stripping endothelial keratoplasty (DSEK).

DESIGN

Prospective, consecutive, comparative, nonrandomized study.

METHODS

Surgery was performed between October 2008 and October 2010 in 52 eyes of 52 consecutive patients with endothelial dysfunction suitable for DSEK. Twenty-two consecutive eyes underwent the new EndoGlide-assisted insertion of donor lenticule and 30 eyes underwent the surgery using the Busin glide. Six-month follow-up data are available for all patients. Clinical details, best-corrected visual acuity, manifest refraction, intraoperative and postoperative complications, and corneal endothelial cell loss were assessed at 6 months after DSEK.

RESULTS

At 6 months after surgery, the best-corrected visual acuity was similar in both groups (0.13 logarithm of the minimal angle of resolution in the EndoGlide eyes as compared with 0.15 logarithm of the minimal angle of resolution in the Busin group; P = .34). Mean spherical equivalent was 0.65 diopter (D) and 0.51 D, and mean refractory cylinder was 1.39 D and 1.08 D, respectively (P = .40). The endothelial cell loss was much lower in the EndoGlide group (25.76%) as compared with the Busin group (47.46%; P < .0001).

CONCLUSIONS

In conclusion, the new EndoGlide results in significantly less endothelial cell loss than Busin glide donor insertion in DSEK. The visual outcomes and refractive changes were similar in both groups.

Corneal higher-order aberrations after Descemet's membrane endothelial keratoplasty

PURPOSE

We compared corneal higher-order aberrations (HOAs) in eyes after Descemet's membrane endothelial keratoplasty (DMEK), Descemet's stripping automated endothelial keratoplasty (DSAEK), and penetrating keratoplasty (PK), and in a control group that had not undergone surgery.

DESIGN

Retrospective analysis of clinical data.

PARTICIPANTS

Thirty eyes of 30 patients who had undergone standard DMEK, 20 eyes of 20 patients after DSAEK, 20 eyes of 20 patients after PK, and 20 eyes of 20 controls were analyzed.

METHODS

In addition to standard postoperative examinations, each participant was analyzed with the Pentacam high-resolution rotating Scheimpflug imaging system (Pentacam HR, Oculus, Wetzlar, Germany). Data were compared between groups.

MAIN OUTCOME MEASURES

Visual acuity and HOAs.

RESULTS

The mean follow-up was 6.5 ± 1.2 months after DMEK, 22.6 ± 11.8 months after DSAEK, and 103.1 ± 74.2 months after PK. There were no statistically significant differences for the anterior 4.0-mm zones between the DMEK group and the controls or between the DMEK and DSAEK groups. The DMEK procedure compared with PK showed statistically significant differences in all terms for the 4.0-mm zones. All combined Zernike terms for mean posterior aberrations of the central 4.0-mm zones showed statistically significant higher aberrations for DMEK compared with controls. The DMEK procedure compared with DSAEK showed statistically significant lower mean values for all combined Zernike terms, except for coma and coma-like terms in the central 4.0-mm zones of the posterior corneal surface. Compared with PK, DMEK showed statistically significant lower mean values for all combined Zernike terms for the central 4.0-mm zones of the posterior corneal surface, except for spherical aberration (SA) and SA-like terms. Best spectacle-corrected visual acuity (BSCVA) after DMEK was statistically significantly better than after DSAEK (P=0.001) and PK (P=0.005). There was no statistically significant difference when BSCVA was compared with controls (P=0.998).

CONCLUSIONS

Both DSAEK and PK exhibit increased posterior corneal HOAs even years after surgery. Patients receiving DMEK display only slight changes in posterior corneal HOAs.

Transient peripheral edema following displaced corneal graft after descemet stripping automated endothelial keratoplasty (DSAEK): case presentation

Background

Descemet's Stripping with Automated Endothelial Keratoplasty (DSAEK) is constantly gaining popularity in the management of endothelial dysfunctions such as bullous keratopathy or Fuchs' dystrophy.

Case Presentation

A 36 year - old man with Fuchs' dystrophy underwent combined phacoemulsification and DSAEK of the right eye. Immediately postoperatively, corneal graft displacement and peripheral corneal edema which remained stable during the first postoperative month were evident on slit lamp examination. Three months after the procedure the peripheral edema had completely resolved and the patients' subjective symptoms were improved.

Conclusions

The purpose of this case presentation is to demonstrate that corneal graft displacement after DSAEK can lead to peripheral corneal edema that can resolve without further intervention such as graft repositioning or replacement.

[Visual acuity and endothelial cell density following Descemet membrane endothelial keratoplasty (DMEK)]

PURPOSE

To assess the clinical outcomes of DMEK in the first series of 120 eyes operated for the treatment of Fuchs endothelial dystrophy in terms of visual acuity and endothelial cell density.

METHODS

The first 120 consecutive eyes that underwent DMEK (i.e. transplantation of an isolated donor Descemet membrane with its endothelium) were evaluated. In all eyes, the best corrected visual acuity (BCVA) before and at 1, 3 and 6 months after surgery, as well as the endothelial cell density (ECD) before and at 6 months were measured.

RESULTS

In eyes with a functional DMEK graft and good visual potential (n=96), the BCVA was ≥ 20/40 (≥ 0.5) in 77% after 1 month, 92% after 3 months, and 95% after six months; ≥ 20/25 (≥ 0.8) in 50%, 63%, and 73% of the cases, and ≥ 20/20 (≥ 1.0) in 23%, 34%, and 45% of the cases at 1, 3, and 6 months respectively. In this group, ECD averaged 2610 (± 185) cells/mm(2) before, and 1770 (± 520) cells/mm(2) at six months after surgery (n=96). In 15 eyes, a secondary Descemet stripping endothelial keratoplasty (DSEK) was performed. In this group, 91% of patients reached a BCVA of ≥ 20/40 (≥ 0.5) and only one patient achieved a BCVA of 0.8 at 6 months after surgery (n=11). Furthermore, ECD averaged 2580 (± 185) cells/mm(2) before and 1310 (± 740) cells/mm(2) at six months (n=13).

CONCLUSION

DMEK provides a fast and high visual rehabilitation. Endothelial cell density loss may be similar to earlier types of endothelial keratoplasty.