Marianne O. Price

Descemet's stripping with endothelial keratoplasty in 200 eyes : Early challenges and techniques to enhance donor adherence

PURPOSE: To describe early challenges and techniques to promote donor tissue adherence in Descemets stripping with endothelial keratoplasty (DSEK). SETTING: Price Vision Group, Indianapolis, Indiana, USA. METHODS: The first 200 consecutive cases of DSEK performed by a single surgeon were analyzed retrospectively. Follow‐up was 7 to 20 months for 124 eyes and 2 to 6 months for 76 eyes. The surgical technique consisted of stripping Descemets membrane and endothelium from the recipients central cornea and transplanting an 8.0 to 9.0 mm disc of donor endothelium and posterior stroma through a 5.0 mm incision, with sutures used only to close the incision. RESULTS: The most frequent challenge was inadequate donor attachment. Using techniques to remove fluid from the donor–recipient graft interface, the donor detachment rate in the last 64 cases was 6%, with half attributable to patient eye rubbing. Detached grafts were reattached by injecting an air bubble to press the donor against the recipient cornea. There were 7 primary graft failures, with only 1 occurring in the second 100 cases, which primarily used microkeratome‐dissected donor tissue. Other complications were infrequent and included pupillary block glaucoma (1), aqueous misdirection syndrome (1), and cataract development in 2 of 27 phakic eyes. The DSEK procedure was performed safely before and after laser in situ keratomileusis (1 each). CONCLUSIONS: Early outcomes in the initial 200 consecutive DSEK procedures suggest the technique provides significant advantages over penetrating keratoplasty, including more rapid healing, more predictable refractive outcomes, and better retention of corneal strength and integrity. Although donor adherence was more challenging, DSEK was technically easier and should be less traumatic to anterior chamber structures than earlier posterior grafting techniques.

Corneal transplant rejection rate and severity after endothelial keratoplasty.

Purpose: To examine the corneal transplant rejection rate and the rate of graft failure subsequent to rejection in the first 2 years after endothelial keratoplasty (EK) and to compare this to background data for similar cases of penetrating keratoplasty (PK). Methods: Anonymized data from consecutive cases of EK [deep lamellar (DLEK) or Descemet stripping (DSEK)] for Fuchs corneal endothelial dystrophy or pseudophakic bullous keratopathy operated on before August 2004 were collected in 4 participating centers. The number and timing of rejection episodes and cases of subsequent graft failure were recorded, together with the time to cessation of topical steroid medication. Two-year postoperative findings were compared with background data for similar patients undergoing PK recorded in the Swedish Corneal Transplant Registry. Results: Rejection episodes were less frequent after EK than PK (P = 0.035). Fifteen (7.5%) of 199 EK cases had a rejection episode in the first 2 years after surgery versus 92 (13%) of 708 PK cases. Graft failure after rejection in EK may have been less frequent than in PK (P = 0.063), with only 1 (6.7%) case of rejection after EK versus 26 (28.3%) cases of rejection after PK proceeding to graft failure. A strong trend toward continued use of low-dose topical steroid medication was observed in the EK group. Eighty percent of EK patients were still taking topical steroid medication 2 years after surgery, whereas topical steroid medication had been ceased within a year of surgery in almost all PK patients in the comparator group. Conclusions: Corneal transplant rejection is less frequent and may be less severe after EK than after PK. It is not yet clear whether these apparent differences are simply a product of relatively prolonged postoperative topical steroid cover in EK patients.

Randomized, Prospective Comparison of Precut vs Surgeon-Dissected Grafts for Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE To determine whether eye bank predissected corneal grafts provide outcomes comparable to surgeon-dissected grafts for Descemet stripping automated endothelial keratoplasty (DSAEK). DESIGN Randomized, prospective, double-masked clinical trial. METHODS Twenty pairs of donor corneas were harvested. One cornea from each pair was randomized to be precut at an eye bank for next-day use. The surgeon dissected the fellow cornea intraoperatively using a comparable microkeratome and protocol. The corneas were randomly assigned to 40 subjects having DSAEK at a single center. Subjects and evaluators were masked and statistical significance was assessed using the paired t test. RESULTS Mean subject age was 71 +/- 12 years and 90% had Fuchs dystrophy. Mean endothelial cell loss was 32% at six months and 34% at one year; the two groups did not differ by a statistically significant amount at either time point (P = .10 and P = .79, respectively). Each group experienced two early dislocations (10%), and grafts were repositioned successfully with a second air bubble. At six months, 28 of 35 patients (80%) had best-corrected vision of 20/40 or better, excluding five patients (12%) with preexisting retinal problems (P = .48). Both groups experienced a mild hyperopic shift (P = .82), and neither had a statistically significant increase in mean refractive cylinder (P = .63). Histology from one subjects eye postmortem demonstrated that endothelial cells had migrated over the exposed edge of the donor stroma a year after surgery. CONCLUSIONS Eye bank precut tissue provided similar endothelial cell loss, visual and refractive outcomes, and detachment rates compared with surgeon-dissected tissue.

Late dislocation of scleral-sutured posterior chamber intraocular lenses

Purpose: To examine a recent series of late scleral‐sutured posterior chamber intraocular lens (PCIOL) dislocations to identify possible causes and preventive measures. Setting: Price Vision Group, Indianapolis, Indiana, USA. Methods: In this retrospective non‐comparative interventional case series, 5 consecutive patients received treatment for dislocated scleral‐sutured PCIOLs between July 2002 and March 2004. Dislocated lenses were resutured or replaced with another scleral‐sutured PCIOL. Results: Dislocation of scleral‐sutured PCIOLs occurred 7 to 14 years after implantation. Four dislocations were spontaneous, and 1 was precipitated by trauma. In each case, the suture affixing 1 or both haptics failed. There was no evidence that the suture had eroded through the tissue or that the knot had untied. Microscopic analysis of an explanted IOL with remnants of the suture attached showed localized degradation and cracking of the polypropylene suture material where it had been embedded in the scleral tissue. Conclusion: Suture‐fixated PCIOLs can dislocate due to degradation of the suture material over time. The use of larger diameter (9‐0 instead of 10‐0) polypropylene suture material and placement of the haptic and sutures in the ciliary sulcus to promote attachment of scar tissue may enhance the long‐term stability of scleral‐fixated PCIOLs.

Central corneal pachymetry in patients undergoing laser in situ keratomileusis

OBJECTIVE To report the preoperative ultrasonic central pachymetric measurements on a large group of eyes undergoing laser-assisted in situ keratomileusis (LASIK) surgery for myopia and myopic astigmatism, to determine whether central corneal thickness is correlated with other geometric features of the eye or is correlated with age or gender, and to discuss the resulting limitations on possible ablation depths. DESIGN Prospective, multisite, cross-sectional study. PARTICIPANTS Eight hundred ninety-six eyes in 450 patients from 21 to 66 years of age. MAIN OUTCOME MEASURES Central corneal thickness and its correlation to intraocular pressure, corneal curvature, axial length, horizontal corneal diameter, refraction, age, and gender. RESULTS The mean central corneal thickness was 550 microm with a standard deviation of 33 and a range of 472 to 651 microm. The lower 25th quantile was 528 microm. The central corneal pachymetry correlated with the mean manual keratometric measurement (P = 0.0001), simulated keratometry (Sim K) (P = 0.0001), and intraocular pressure (P = 0.0001). Central corneal thickness did not correlate with axial length, age, gender, horizontal corneal diameter, and refraction. CONCLUSION This clinical study shows there is a substantial range of central corneal thickness in normal myopic eyes. With LASIK, there is a general concern that one should not thin the cornea further than a given amount. Because this study shows wide variability in central corneal thickness, it is prudent to measure pachymetry before surgery and gear treatment plans accordingly. Possible treatment limits relative to corneal thickness are discussed.

Endothelial keratoplasty – a review

From its inception over a century ago, penetrating keratoplasty grew to become the most common and most successful form of solid tissue transplantation. Yet clinicians have long recognized the limitations of full‐thickness corneal transplants, including prolonged visual rehabilitation, unpredictable refractive changes, susceptibility to ocular surface complications and vulnerability to traumatic wound rupture. Selective replacement of diseased or damaged posterior corneal layers was conceptualized and implemented a half century ago. However, it has only been within the past decade that improved techniques and instrumentation have allowed endothelial keratoplasty (EK) to become the preferred treatment for patients with endothelial dysfunction. EK provides more rapid visual recovery, minimizes induced astigmatism and, most importantly, better maintains globe integrity than penetrating keratoplasty. Descemet stripping automated EK is currently the most widely used method. This article covers how EK techniques have evolved over time, considers who is or is not an appropriate candidate for EK, describes Descemet stripping automated EK methods and instrumentation, discusses EK postoperative complications and management and compares visual recovery, refractive outcomes and endothelial cell loss with that of standard penetrating keratoplasty.

Endothelial Keratoplasty: A Revolution in Evolution

Endothelial keratoplasty (EK) is continually evolving both in surgical technique and clinical outcomes. Descemets 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 Descemets membrane endothelial keratoplasty, Descemets 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.

Graft rejection episodes after Descemet stripping with endothelial keratoplasty: part two: the statistical analysis of probability and risk factors

Aim: To investigate risk factors and probability of initial immunological graft rejection episodes after Descemet stripping with endothelial keratoplasty (DSEK). Methods: Outcomes of 598 DSEK cases from a single tertiary referral centre were reviewed. Risk factors and probability of rejection were assessed by multivariate Cox proportional hazards modelling. Results: Rejection episodes occurred in 54 eyes of 48 patients. Estimated probability of a rejection episode was 7.6% by 1 year and 12% by 2 years after grafting. Relative risk of rejection was five times higher for African–American patients compared with Caucasians (p = 0.0002). Eyes with pre-existing glaucoma (9%) or steroid-responsive ocular hypertension (27%) had twice the relative risk of rejection (p = 0.045) compared with eyes that did not have those problems. Patient age, sex and corneal diagnosis did not significantly influence rejection risk. Risk of rejection was not increased when fellow eyes were grafted within 1 year of the first eye (p = 0.62). Conclusions: Pre-existing glaucoma or steroid-responsive ocular hypertension and race were the two factors that independently influenced relative risk of rejection after DSEK. Rejection risk was not increased if the fellow eye was grafted within the prior year with DSEK.

Endothelial keratoplasty to restore clarity to a failed penetrating graft.

Purpose: To describe an adaptation of endothelial keratoplasty to restore corneal clarity to a prior penetrating keratoplasty (PK) with endothelial decompensation. Methods: A surgeons initial 7 consecutive cases using endothelial keratoplasty for treatment of failed prior PK were retrospectively analyzed. The treated eyes had all experienced endothelial decompensation after previously having clear corneal transplants. Instead of repeating the PK, a partial-thickness donor button, composed of posterior stroma with Descemet membrane and endothelium, was grafted to the posterior surface of the failed full-thickness donor graft. In 6 of the 7 cases, the only sutures were those used to close a 5-mm scleral tunnel incision. The donor button was initially held in place with an air bubble and later attached on its own. Results: In all cases, the new donor button adhered to and cleared the edema from the previous penetrating graft. Within 3 months of endothelial keratoplasty, best-corrected visual acuity had improved in 6 of the 7 cases compared with the preoperative vision. Conclusion: Standard PK usually takes months to years to heal sufficiently to remove sutures and provide patients with a stable refraction and a wound strong enough to withstand minor trauma. Using endothelial keratoplasty to rehabilitate a failed graft may provide faster visual recovery, a tectonically stronger eye, and a reduced period of disability compared with repeating the PK. Endothelial keratoplasty may be a particularly useful alternative for treating penetrating grafts that achieved acceptable refractive and ocular surface results but failed because of endothelial dysfunction.

Visual Acuity and Intraocular Pressure after Descemet's Stripping Endothelial Keratoplasty in Eyes with and without Preexisting Glaucoma

PURPOSE (1) To characterize the pattern of intraocular pressure (IOP) changes after Descemets stripping endothelial keratoplasty (DSEK) in patients without preexisting glaucoma and in those with preexisting glaucoma, with and without prior glaucoma surgery. (2) To compare vision and IOP outcomes among the 3 groups. DESIGN A retrospective chart review. PARTICIPANTS A total of 805 DSEK cases performed in 641 patients by a single surgeon from December 2003 to August 2007 were available in the database. Only the first-treated eye of each patient with at least 1-year follow-up was included. Four hundred cases qualified: 315 eyes had no glaucoma (C); 64 eyes had glaucoma with no previous glaucoma surgery (G); and 21 eyes had prior glaucoma surgery (GS). Eyes with preexisting retinal problems were included in the analysis. METHODS Data analysis included calculation of incidence of postoperative IOP elevation. The study criteria for postoperative IOP elevation were IOP > or =24 mmHg or IOP increase > or =10 mmHg from baseline. Kruskal-Wallis test was used to compare visual acuity (VA) and IOP among the 3 groups preoperatively and at 1-, 3-, 6-, and 12-month postoperative visits. MAIN OUTCOME MEASURES Visual acuity (Snellen) and IOP (millimeters of mercury). RESULTS The incidence of postoperative IOP elevation by the study criteria was 35%, 45%, and 43% for groups C, G, and GS, respectively. Elevated IOP was medically managed by initiating or increasing glaucoma medications or reducing steroids in 27%, 44%, and 38% of the patients in groups C, G, and GS, respectively. A subsequent glaucoma procedure was performed in 0.3%, 5%, and 19% of patients in groups C, G, and GS, respectively. Only the control group had statistically significant IOP elevation at 12 months (median increase of 2 mmHg) when compared with baseline (P<0.0001). All 3 groups had statistically significant improvement in vision at 12 months when compared with baseline (12-month median VA = 20/40 for C and G; and 20/50 for GS, P<0.0001). CONCLUSIONS All groups had a substantial incidence of IOP elevation after DSEK. Close monitoring of IOP is warranted. In this cohort, preexisting glaucoma did not seem to have a negative effect on VA after DSEK. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.