Clinicopathologic findings in failed descemet stripping automated endothelial keratoplasty

A Novel Murine Model of Endothelial Keratoplasty

PURPOSE

The purpose of this study was to establish a murine model of endothelial keratoplasty.

METHODS

Endothelial keratoplasty (EK) was performed using C57BL/6 donor and BALB/c recipient mice. The central endothelium and Descemet membrane were removed from the recipient cornea, and a 1.5-mm posterior lamellar donor graft was made adherent to the recipient cornea with a small amount of viscoelastic. Mice were followed through slitlamp microscopy postoperatively, and OCT was used to assess the cornea and anterior chamber and measure central corneal thickness. Histology and immunohistochemistry were performed to confirm graft adherence and endothelial cell morphology.

RESULTS

Successfully attached EK grafts were visualized in all transplanted animals. Histology and immunostaining confirmed proper graft orientation and adherence, as well as the presence of donor endothelium on transplanted grafts. We observed maximal corneal edema in all animals at day 1 postoperatively which gradually subsided. EK graft survival was 97% at 8 weeks.

CONCLUSIONS

In this study, we describe a novel murine model for EK which we anticipate will enable detailed investigation into the cellular and molecular mechanisms involved in EK pathobiology.

Epithelial downgrowth leading to graft rejection after penetrating keratoplasty

PURPOSE

To report a case of epithelial downgrowth after penetrating keratoplasty.

CASE DESCRIPTION

A 58-year-old man presented with graft rejection in his three-month-old, repeat penetrating keratoplasty. Examination revealed centripetal opacification of the posterior cornea due to deep epithelization. He had new retro-corneal membranes and anterior uveitis. Specular microscopy and anterior segment optical coherence tomography were performed, and a clinical diagnosis of epithelial downgrowth was made. The patient had intracameral injections with 5-fluorouracil (5FU) and achieved resolution of intraocular findings after treatment.

CONCLUSIONS

Epithelial downgrowth is an uncommon complication of penetrating keratoplasty. It affects the patients' visual acuity and graft survival. Clinical observation is preferred in severe cases due to the high risk of intraocular damage; intracameral 5FU promises to be a good option in these cases.

[Morphological features of the cornea in eyes with pseudophakic bullous keratopathy and Fuchs endothelial corneal dystrophy]

PURPOSE

To evaluate the morphological features of posterior corneal layers in pseudophakic bullous keratopathy (PBK) and Fuchs endothelial corneal dystrophy (FECD).

MATERIAL AND METHOD

The study included 20 patients (20 eyes) aged 73.8±7.8 with PBK and 24 patients (25 eyes) aged 72.5±10.6 with FECD. Central corneal thickness was measured in all eyes before the surgery by anterior segment optical coherence tomography (AS-OCT, RTVue-100, Optovue, USA). All patients underwent corneal transplantation (DSAEK or DMEK). Postoperative donor graft status was assessed as attached or detached by AS-OCT (RTVue-100, Optovue, USA). Specimens of Descemet's membranes (DMs) were obtained intraoperatively and investigated histologically (hematoxylin and eosin staining). Morphometric analysis was performed using optical microscope Leica DM-2500 (Digital Color Camera Leica DFC295) and ImageScope M software.

RESULTS

There was no difference in thickness of DMs' prenatal anterior banded layer (2.58±0.49 μm) and postnatal posterior non-banded layer (11.30±2.64 μm) between PBK and normal cornea. In FECD eyes, DM was significantly thickened by additional collagen layer and guttate excrescences (postnatal layer thickness - 16.62±4.34 μm). Morphological study of the DMs of patients with graft detachment in the early postoperative period revealed residual stromal collagen fibrils that were fixed to the area with dense extracellular matrix.

CONCLUSION

The study shows that chronic corneal edema is associated with pathological morphological changes in the posterior corneal layers in PBK and FECD. Individual features of the dense extracellular matrix in the DMs may play a key role in the attachment of donor graft to the corneal stroma and affect the postoperative outcome.

Clinicopathologic Correlations of Retrocorneal Membranes Associated With Endothelial Corneal Graft Failure

PURPOSE

To provide clinicopathologic correlations for retrocorneal membranes associated with Descemet stripping automated endothelial keratoplasty (DSAEK) failure.

DESIGN

Retrospective case series.

METHODS

The specimens and medical records of the patients diagnosed with clinically significant retrocorneal membranes associated with DSAEK failure at the Bascom Palmer Eye Institute or the University of Miami Veterans Hospital between October 2015 and March 2020 were reviewed for demographics, clinical presentation, comorbidities, and surgeries performed. Histopathologic analysis was performed on hematoxylin-eosin and periodic acid-Schiff sections. Immunohistochemical studies were performed for smooth muscle actin (α-SMA), pancytokeratin, and CK7. Immunofluorescence was performed for vimentin, N-cadherin, ROCK1, RhoA, ZEB1, and Snail.

RESULTS

A total of 7 patients (3 male and 4 female) were identified to have a clinically significant retrocorneal membranes at the time of graft failure. The average age at the time of first DSAEK was 70 years (range: 55-85 years). All patients were pseudophakic and had a glaucoma drainage device in place; 1 had a history of failed DSAEK. Ranging from 0 to 47 months after surgery, a variably thick retrocorneal fibrous membrane was observed, eventually leading to graft failure. Four patients underwent subsequent penetrating keratoplasty and 3 underwent repeat DSAEK. On histopathologic evaluation, a pigmented fibrocellular tissue was identified along the posterior margin of the corneas and DSAEK buttons in all cases. Further characterization with immunohistochemistry and immunofluorescence demonstrated membranes to be negative for pancytokeratin and positive for α-SMA, vimentin, CK7, N-cadherin, ZEB1, Snail, ROCK1, and RhoA.

CONCLUSIONS

Fibrocellular retrocorneal membrane proliferation may be associated with DSAEK failure in patients with previous glaucoma drainage device surgery. Our results demonstrate myofibroblastic differentiation and a lack of epithelial differentiation. Positivity for markers of an endothelial-to-mesenchymal transition indicates possible endothelial origin and could be the hallmark for future targeted pharmacotherapy.

Exophiala Keratitis following Descemet Stripping Automated Endothelial Keratoplasty

Purpose. To report a case with Exophiala spp. keratitis in a Portuguese patient. Methods. A case report with deep corneal brown-pigmented infiltrates that developed 2 months after a Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) for pseudophakic bullous keratopathy. Results. Diagnosis was established by positive direct examination and cultures from the surgically obtained corneal button. Slit-lamp images and anterior segment optical coherence tomography (AS-OCT) scans were obtained. Conclusion. This is the first described case of fungal keratitis caused by Exophiala spp. in Portugal and, to our knowledge, the first case following DSAEK in the literature.

Epithelial downgrowth after Descemet membrane endothelial keratoplasty

PURPOSE

To describe a patient with epithelial downgrowth after Descemet membrane endothelial keratoplasty.

METHODS

Case report.

RESULTS

A 73-year-old woman underwent triple Descemet stripping automated endothelial keratoplasty for cataract and corneal edema secondary to Fuchs endothelial dystrophy in the left eye elsewhere. Three years later, Descemet membrane endothelial keratoplasty was performed at our department due to graft failure. One month after the operation, her vision improved to 20/32 and maintained stable. At the 14-month visit, her visual acuity decreased, and a routine examination revealed epithelial downgrowth at the posterior surface of the cornea and partly beneath the graft, accompanied by presumed graft rejection. Therefore, repeat Descemet membrane endothelial keratoplasty with epithelial scraping and intracameral injection of 5-fluorouracil was indicated. She recovered 20/25 vision by 1 month after the surgery. However, small sheet-like epithelial downgrowth recurred 1 month later. The epithelial downgrowth was limited to the peripheral margin of the Descemet membrane endothelial keratoplasty graft and did not affect the visual axis. Epithelial downgrowth showed "islands" with connection between epithelial downgrowth and clear corneal incision on anterior segment optical coherence tomography images. Histopathologic evaluation of the removed Descemet membrane endothelial keratoplasty graft confirmed conjunctival epithelium as the source. Under close observation at the current 4-year follow-up, the epithelial downgrowth remained stable and localized and her vision increased to 20/20.

CONCLUSION

Epithelial downgrowth can occur after Descemet membrane endothelial keratoplasty. The limited progression of epithelial downgrowth in this patient suggests that this condition after Descemet membrane endothelial keratoplasty even in the recurrence stage may cause less damage than expected and may only need to be observed closely if no progression occurs.

Deep Anterior Lamellar Keratoplasty After Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To report the indications and long-term outcomes of deep anterior lamellar keratoplasty (DALK) performed after Descemet stripping automated endothelial keratoplasty (DSAEK) in cases of visually significant stromal opacities.

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

Setting: Private hospital.

STUDY POPULATION

Thirteen eyes that underwent DALK after DSAEK at our institution. Indications for DALK after DSAEK included both stromal opacities persisting after DSAEK and stromal opacities occurring secondarily in post-DSAEK corneas. DALK was always performed in a standardized fashion including exchange of a disc of full-thickness recipient cornea (up to the DSAEK stromal surface),7.0 mm in diameter, with a donor lamella obtained by microkeratome-assisted dissection, punched to 7.0 mm and sutured into place with a double running 10-0 nylon suture.

MAIN OUTCOME MEASURES

Best spectacle-corrected visual acuity (BSCVA), manifest refraction, and endothelial cell density (ECD).

RESULTS

Mean follow-up was 26 ± 18 months (range = 6-60 months). Indications for DSAEK were full-thickness graft failure (n = 8), DSAEK graft failure (n = 3), and pseudophakic bullous keratopathy (n = 2). Indications for subsequent DALK were persisting stromal opacity (n = 9) and stromal opacities newly occurred after DSAEK as a result of HSV keratitis (n = 2) or interface infection (n = 2). After complete suture removal, mean BSCVA was 20/28 (0.14 ± 0.8 logMAR) in eyes without ocular comorbidities affecting visual acuity (n = 7), while refractive astigmatism was within 4 diopter (D) in all but 1 eye (average = 3.2 ± 1.4 D). No intraoperative complications were recorded.

CONCLUSIONS

Performing DALK on DSAEK eliminates the need for open-sky surgery, achieving visual results comparable to those of penetrating keratoplasty, while sparing a healthy endothelial graft.

Splitting of the Recipient's Descemet Membrane in Descemet Membrane Endothelial Keratoplasty-Ultrastructure and Clinical Relevance

PURPOSE

In Descemet membrane endothelial keratoplasty (DMEK), lamellar splitting of the Descemet membrane (DM) may occur during stripping of host DM, leaving residual DM on the recipient's DMEK interface. The purpose of this study was to determine the incidence rate of lamellar splitting of DM during DMEK and to describe the ultrastructure of DM in these eyes.

DESIGN

Retrospective consecutive case series.

METHODS

setting: Institutional, single-center.

PATIENT POPULATION

Total of 664 eyes with Fuchs endothelial corneal dystrophy (FECD) scheduled for primary DMEK.

INTERVENTION

DMEK.

MAIN OUTCOME MEASURES

The incidence rate of lamellar DM splitting in the recipients' eyes; ultrastructural alterations of stripped DM specimens (transmission electron microscopy); preoperative best-corrected visual acuity (BCVA), central corneal thickness (CCT), and prevalence of diabetes mellitus.

RESULTS

Sixty-three of 664 eyes (9.5%) with FECD showed lamellar splitting of DM resulting in the dissociation of 2 separate layers. Transmission electron microscopy revealed accumulations of banded and wide-spaced collagen between the thicker posterior banded layer and the thin anterior banded layer, which is adhesive to the corneal stroma. Lamellar splitting occurred along these abnormal collagen inclusions, demarcating the borderline between both layers of DM.

CONCLUSIONS

Lamellar DM splitting occurs during DM stripping in almost 10% of eyes with FECD. This phenomenon appears to be caused by abnormal collagenous material deposits at the borderline between anterior and posterior layers of DM.

Candida Interface Infections After Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To describe 2 Candida interface keratitis infections occurring in the setting of positive donor rim cultures from precut corneal tissue used for Descemet stripping automated endothelial keratoplasty (DSAEK) and the ensuing public health investigation.

METHODS

Following 2 clinical Candida interface keratitis infections, patients from 2012 to 2014 in the same surgical center were evaluated for bacterial and fungal rim cultures and subsequent infection. All cases of fungal infections occurring post-DSAEK were analyzed. Data included patient demographics, surgical technique, donor rim cultures, donor mate outcomes, clinical courses, and outcomes. A review of the relevant literature was also undertaken.

RESULTS

From 2012 to 2014, among 99 DSAEK procedures performed, 7 (7.1%) donor rim cultures were positive for fungi. Use of this tissue with positive donor rim cultures resulted in 2 (28.6%) episodes of confirmed fungal interface keratitis, both Candida species, and presumptive treatment in an additional 2 patients. An investigation did not identify any breach in sterile technique or procedures by the surgeon or surgery center. Our literature review identified 15 reports of postoperative fungal infection associated with DSAEK, of which 11 involved Candida spp.

CONCLUSIONS

While postoperative infection remains rare, our 2 additional cases along with those previously reported suggest that DSAEK may be susceptible to infection with Candida spp. Furthermore, this report of correlated rim cultures and clinical infection suggests a need for reevaluation of the utility of obtaining routine corneoscleral donor rim fungal culture.

A case of severe corneal flattening after Descemet stripping endothelial keratoplasty

PURPOSE

To report a case of extreme corneal flattening after initially uneventful Descemet stripping endothelial keratoplasty (DSEK).

METHODS

A 76-year-old man underwent uneventful DSEK for pseudophakic bullous keratopathy (PBK) in his left eye. Postoperative evaluations were performed using anterior segment optical coherence tomography and biomicroscopy.

RESULTS

The DSEK graft showed full adherence to the host stroma. Two weeks after surgery, the transplanted cornea developed pronounced flattening of the central corneal curvature accompanied by graft folds and remained unchanged until the most recent follow-up 20 weeks after surgery.

CONCLUSIONS

Severe corneal flattening may be an undescribed complication occurring after uneventful DSEK, without any concomitant ocular pathology or detectable cause.

Descemet membrane endothelial keratoplasty as treatment for graft failure after descemet stripping automated endothelial keratoplasty

PURPOSE

To investigate the outcome of Descemet membrane endothelial keratoplasty (DMEK) in patients with graft failure after Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

Retrospective cohort study.

METHODS

setting: Institutional.

STUDY POPULATION

Fifteen eyes of 15 patients that underwent DMEK for graft failure with corneal decompensation following DSAEK were analyzed; 15 eyes with primary DMEK for Fuchs corneal dystrophy were included as control group.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), endothelial cell density (ECD), central corneal thickness (CCT), and rebubbling rate.

RESULTS

DMEK surgery was successful in all cases of both groups. Mean BCVA (logMAR) before DMEK was 1.27 ± 0.34 in the DMEK after DSAEK group and 1.0 ± 0.40 in the Primary DMEK group. After DMEK, mean BCVA increased significantly to 0.23 ± 0.21 (P = .012, DMEK after DSAEK group) and 0.29 ± 0.23 (P = .042, Primary DMEK group) after 3 months. There were no significant differences in mean BCVA between both groups at each visit. The rebubbling rate was 13% in the DMEK after DSAEK group and 40% in the Primary DMEK group (P = .1). Mean CCT decreased significantly in both groups 1 month after DMEK (P < .05). Mean ECD and change of ECD did not differ significantly between both groups at each visit (P > .05).

CONCLUSION

The results after DMEK as a procedure to treat graft failure after DSAEK were as good as in patients that underwent DMEK as primary intervention to treat advanced Fuchs dystrophy. This indicates that the optical quality can be reestablished by DMEK in patients with failed DSAEK.

Clinicopathology of graft detachment after Descemet's membrane endothelial keratoplasty

PURPOSE

To investigate pathomechanisms involved in graft detachment after Descemet's membrane endothelial keratoplasty (DMEK) and its clinical implications.

METHODS

In a prospective case series, 30 eyes with Fuchs' endothelial dystrophy underwent DMEK. Intraoperatively obtained recipients' endothelium-Descemet's membranes (EDMs) were investigated histologically and immunohistochemically. The postoperative donor graft status was categorized as attached or detached. Clinical and morphological parameters were analysed between the study groups.

RESULTS

The detachment rate was 40% (12/30). There was no significant difference in postoperative visual acuity between the groups, but visual recovery was delayed in eyes with initially detached grafts. Gender, age, preoperative central corneal thickness or best corrected visual acuity did not influence the detachment rate. However, separation and disruption of the anterior banded layer (ABL) were frequently observed in patients with graft detachment, and ABL thickness was identified as a significant predictor for graft detachment. The ABL thickness was 2.5 ± 0.9 μm and 3.5 ± 1.6 μm in patients with attached and detached grafts, respectively. Immunohistologically, a deficiency of fibronectin and cytokeratin was observed within the ABL of patients with detached grafts. In contrast, a complete removal of the EDM with residual stromal collagen fragments was observed in patients with adherent grafts.

CONCLUSIONS

Incomplete removal of the EDM, with residual ABL fragments on the recipients' corneal stroma, may be a risk factor for graft detachment after DMEK. The separation and disruption of the ABL might be promoted by a deficiency of matrix proteins, stronger biomechanical properties and a firm adherence to the posterior corneal stroma.

Cellular and extracellular matrix modulation of corneal stromal opacity

Stromal transparency is a critical factor contributing to normal function of the visual system. Corneal injury, surgery, disease and infection elicit complex wound healing responses that serve to protect against insults and maintain the integrity of the cornea, and subsequently to restore corneal structure and transparency. However, in some cases these processes result in prolonged loss of corneal transparency and resulting diminished vision. Corneal opacity is mediated by the complex actions of many cytokines, growth factors, and chemokines produced by the epithelial cells, stromal cells, bone marrow-derived cells, lacrimal tissues, and nerves. Myofibroblasts, and the disorganized extracellular matrix produced by these cells, are critical determinants of the level and persistence of stromal opacity after corneal injury. Decreases in corneal crystallins in myofibroblasts and corneal fibroblasts contribute to cellular opacity in the stroma. Regeneration of a fully functional epithelial basement membrane (BM) appears to have a critical role in the maintenance of corneal stromal transparency after mild injuries and recovery of transparency when opacity is generated after severe injuries. The epithelial BM likely has a regulatory function whereby it modulates epithelium-derived growth factors such as transforming growth factor (TGF) β and platelet-derived growth factor (PDGF) that drive the development and persistence of myofibroblasts from precursor cells. The purpose of this article is to review the factors involved in the maintenance of corneal transparency and to highlight the mechanisms involved in the appearance, persistency and regression of corneal opacity after stromal injury.

The clinical characteristics of fungal keratitis in eyes after Descemet's stripping and automated endothelial keratoplasty

The purpose of this study was to describe the clinical characteristics of fungal keratitis caused by Candida albicans in an eye after Descemet stripping automated endothelial keratoplasty (DSAEK). A 72-year-old male with a history of three trabeculectomies, cataract surgery, and two DSAEK procedures developed a corneal ulcer in his right eye two years after his last DSAEK. Fungal keratitis was most likely related to the immunosuppressive conditions that occurred due to the previous operations, the continuous use of steroid eye drops, and the use of disposable soft contact lenses. A smear and culture from the ulcer detected Candida albicans. Slit-lamp examination showed the characteristic feature was the presence of interface infiltrates located between the host and the graft cornea and in the enlarged area around the ulcer. Two weeks after intense antimycotic treatments with voriconazole, miconazole, and natamycin, perforation of the cornea occurred and further therapeutic penetrating keratoplasty was required. Histological analysis revealed an accumulation of infiltrated cells and fibrotic tissue. The poor prognosis for fungal keratitis that occurs in eyes after undergoing DSAEK may be related to the rapid expansion of inflammatory cells through the interface between the host and the graft. In eyes that develop fungal keratitis after DSAEK, special attention should be paid to the possibility that perforation could occur in these patients.

Detection of herpes simplex virus type 1 in failed descemet stripping automated endothelial keratoplasty grafts

PURPOSE

To determine the prevalence of herpes simplex virus type 1 (HSV-1) DNA in failed Descemet membrane stripping automated endothelial keratoplasty (DSAEK) grafts.

METHODS

A retrospective interventional case series of patients with DSAEK graft failure treated at the New York Eye and Ear Infirmary between January 2009 and July 2012 was performed. Repeat DSAEK, penetrating keratoplasty, or keratoprosthesis procedure was subsequently performed on eyes with failed grafts. All failed grafts were examined immunohistochemically and with qualitative real-time polymerase chain reaction for HSV-1 DNA. In HSV-1-positive cases, corneoscleral donor rims from the original DSAEK procedures were also examined immunohistochemically and with polymerase chain reaction.

RESULTS

Fifty-one failed DSAEK grafts from 50 eyes of 49 patients were identified. Indications for DSAEK were pseudophakic bullous keratopathy (28/51, 55%), Fuchs corneal endothelial dystrophy (12/51, 23%), failed penetrating keratoplasty (7/51, 14%), corneal decompensation from glaucoma (2/51, 4%), herpetic endotheliitis (1/51, 2%), and failed DSAEK (1/51, 2%). Forty-three grafts (83%) were primary DSAEK graft failure. HSV-1 DNA was isolated from 2 of 51 failed DSAEK grafts (4.0%). The corresponding corneoscleral donor rims did not demonstrate the presence of HSV-1.

CONCLUSIONS

Based on our results, HSV-1 infection plays a minor role in DSAEK graft failure. The data suggest that recipient reactivation, rather than donor transmission, plays a role in HSV infection.

Interface haze associated with topical nonsteroidal anti-inflammatory drug use after descemet stripping automated endothelial keratoplasty

PURPOSE

To determine if topical nonsteroidal anti-inflammatory drug (NSAID) use after Descemet stripping automated endothelial keratoplasty (DSAEK) is associated with the development of interface haze.

METHODS

A retrospective case-control study of patients undergoing DSAEK surgery.

RESULTS

Of the 61 patients receiving topical NSAIDs, 51% were noted to develop interface haze, and 9% of the control group (N=100, no NSAID) developed haze. There was no significant difference in best corrected visual acuity between the 2 groups.

CONCLUSIONS

Topical NSAID use is associated with the development of interface haze, although it may not be visually significant and could be related to confounding factors.

Comparative outcomes of penetrating and component endothelial cell corneal allografts in outbred sheep

Lamellar (component cell) corneal transplantation is replacing penetrating keratoplasty for some corneal disorders in humans, but the relative risks of immunological graft rejection for the two procedures remain uncertain. A model of component endothelial cell keratoplasty (endokeratoplasty) was developed in outbred sheep. Clinical and histological graft outcomes after endokeratoplasty were then compared with contemporaneous penetrating corneal allografts. No topical or systemic immunosuppression was administered to any recipient sheep. Endothelial cell allografts (n = 10) took significantly longer to achieve perfect transparency following surgery than did penetrating corneal grafts (n = 7) (day 10 vs. day 4; p = 0.003; two-tailed Mann-Whitney U test). The median day to rejection of penetrating grafts was postoperative day 18; for endothelial cell grafts, it was day 48 (p = 0.04; two-tailed Mann-Whitney U test). The clinical courses of the two procedures were therefore quite different. Penetrating grafts gained clarity quickly but exhibited rapid graft neovascularization. Clinical rejection was preceded by inflammation in the anterior segment. Endothelial cell grafts exhibited a fluctuating, more indolent course of opacification, although all did eventually fail. Histological analysis confirmed immunological rejection in all failed grafts, but with different patterns of leukocytic infiltration in endokeratoplasties compared with penetrating keratoplasties. Inflammatory cells in endothelial cell grafts were generally fewer in number and were more often found in the posterior stroma. We conclude that, in the absence of immunosuppression, all endothelial cell allografts do undergo immunological rejection, albeit at a slower rate than penetrating grafts.

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.

Simultaneous Interface Candida Keratitis in 2 Hosts Following Descemet Stripping Endothelial Keratoplasty With Tissue Harvested From a Single Contaminated Donor and Review of Clinical Literature

PURPOSE

The objective of this study was to report 2 cases of interface fungal keratitis in 2 separate patients following Descemet stripping automated endothelial keratoplasty (DSAEK) with tissue harvested from the same donor.

DESIGN

This was a retrospective simultaneous interinstitutional hosptial-based case reports.

METHODS

Two patients with corneal infections following DSAEK were identified from 2 individual practices. Both patients had undergone DSAEK from the same donor. Preoperative and postoperative eye examination included visual acuity, anterior and posterior segment evaluations, and clinical follow-up course from the time of surgery. Methods of medical therapy and surgical intervention are additionally discussed.

RESULTS

The 2 patients presented in our series present with interface fungal keratitis postoperatively in the face of the original source coming from a single donor (patient 1: 7 days postoperatively and patient 2: 7 weeks postoperatively). As medical treatment failed in both cases, surgery was undertaken in both cases (therapeutic penetrating keratoplasty). With prompt recognition as well as medical and surgical treatment, patient 1 achieved best corrected visual acuity of 20/30 at 6 months postoperatively, and patient 2 had best corrected visual acuity of 20/80 at 10 months postoperatively.

CONCLUSIONS

Fungal keratitis following DSAEK occurs in a sequestered space and therefore represents a treatment challenge with potentially devastating outcome. We recommend an aggressive surgical approach with early removal of the donor button and irrigation with intracameral antifungal agents.

Corneal regrafting after endothelial keratoplasty

PURPOSE

To determine the incidence of corneal regrafting after endothelial keratoplasty (EK) and to explore the possible reasons for repeat EK and subsequent penetrating keratoplasty (PK).

METHODS

This retrospective cohort study examined the occurrence of corneal regrafts among 803 eyes of 751 patients who underwent initial EK from January 2004 through February 2009 using donor corneas distributed by a single eye bank. Regression models and life tables evaluated the effects of donor corneal characteristics on the probability of a regraft.

RESULTS

Corneal regrafting after EK occurred in 119 eyes (15%), including 68 with repeat EK and 51 with subsequent PK. Ninety-five regrafts (80%) occurred within 1 year of EK, with 39 (33%) during the first postoperative month. Three years after EK, the cumulative probability of repeat EK was 11% and was 9% for subsequent PK. The secular trend in regrafting indicated an average 4% decline per year from 2005 to 2008. The odds of regrafting occurred less often (P = 0.004) with 202 eye bank-processed corneas than with 601 surgeon-prepared tissues. The cumulative probability of repeat EK was increased if donor corneas were maintained in preservation medium for more than 7 days (P = 0.02). Older donor age, death-to-preservation interval, or lower endothelial density was not significantly associated with repeat keratoplasty.

CONCLUSIONS

Regrafting after EK is becoming less common, possibly because of surgical experience and technical innovations such as eye bank processing of precut tissues. Timely screening and distribution of donor corneas may foster graft survival.

Myofibroblast metaplasia after descemet membrane endothelial keratoplasty

PURPOSE

To describe myofibroblastic metaplasia of corneal endothelial cells in 2 cases with impaired visual function despite complete graft adherence after Descemet membrane endothelial keratoplasty (DMEK).

DESIGN

Interventional case series.

METHODS

In 2 of 90 consecutive DMEK surgeries, the cornea failed to clear up to 6 months postoperatively despite complete graft attachment. After secondary penetrating keratoplasty, both corneal buttons were examined using histopathologic analysis and transmission electron microscopy.

RESULTS

Light microscopy revealed distinct corneal endothelial cell attenuation with the presence of an abnormal posterior collagenous layer in both cases. Most of the remaining endothelial cells had an elongated fibroblast-like appearance with immunopositivity for α-smooth muscle actin indicative of myofibroblast metaplasia. Transmission electron microscopy showed a slightly thickened Descemet membrane with an abnormal posterior fibrillar collagenous layer and a myofibroblast-like transformation of the remaining endothelial cells. Descemet membrane grafts closely adjoined the collagen lamellae of the host corneal stroma similar to the Descemet membrane-stroma interface of a normal cornea.

CONCLUSION

Myofibroblastic metaplasia of attenuated corneal endothelial cells with formation of an abnormal posterior collagenous layer may contribute to an impaired visual function despite complete graft adherence after Descemet membrane endothelial keratoplasty (DMEK).

Fibrocellular contraction of a lamellar posterior corneal graft

Purpose

To report a case of progressive fibrotic contraction of the posterior lamellar graft after initially successful Descemet's stripping automated endothelial keratoplasty (DSAEK).

Methods

Retrospective report of clinical data and histopathological analysis of excised corneal tissue.

Results

A 63-year-old woman underwent uncomplicated DSAEK in her left eye due to endothelial dystrophy. During the first months after surgery, her visual acuity was 0.3, and a semilunar contraction gradually appeared at the edge of the graft. Over the following months, the fibrotic changes progressed and visual acuity decreased, with no improvement after uncomplicated cataract surgery. A successful penetrating keratoplasty was performed, and the excised corneal button with an attached posterior lamellar graft was histologically examined. The affected part of the graft consisted of a thickened fibrocellular tissue positive for glycosaminoglycans and smooth muscle actin.

Conclusions

The present case demonstrates asymmetric fibrotic contraction of a DSAEK graft.