Histopathologic Examination of Failed Grafts in Descemet's Stripping with Automated Endothelial Keratoplasty

Descemet Membrane Endothelial Keratoplasty in Aphakic, Aniridic, and Vitrectomized Eyes: A Review

PURPOSE

The aim of this review is to examine the techniques, complications, and outcomes of Descemet membrane endothelial keratoplasty (DMEK) in aphakic, aniridic, and vitrectomized eyes.

METHODS

A literature search was conducted in the MEDLINE database (via PubMed), using as keywords "(DMEK) AND (aphakia OR aniridia OR vitrectomy OR vitrectomized)." The research was limited to 10 years (January 2014-March 2024), in view of lack of literature before 2014. Articles, including case reports and case series, were included.

RESULTS

Twenty articles were included. No randomized controlled trials were found nor comparative studies with more than 1 technique used. Mean rebubbling rate in complex eyes was 29%, whereas mean endothelial cell loss at 6 months was 37%. The mean postoperative visual acuity improved from 1.47 logarithm of the minimal angle of resolution to 0.7 logarithm of the minimal angle of resolution.

CONCLUSIONS

Despite being more challenging, compared with the techniques reported in literature, DMEK can be considered a valid option for the management of endothelial decompensation in complex eyes, with rebubbling rate and endothelial cell loss at 6 months, which are similar to non-complex eyes.

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.

Descemet membrane endothelial keratoplasty in vitrectomized eyes: a case series of outcomes and complications

BACKGROUND

The aim of this study was to evaluate the clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in vitrectomized eyes.

METHODS

A multi-surgeon, retrospective case series of previously vitrectomized eyes that underwent DMEK between 2013 and 2018 at Moorfields Eye Hospital. Patients' demographics, preoperative, intraoperative and postoperative data were collected.

RESULTS

In total, 14 eyes of 13 patients, aged 63 ± 14.6 years were included. Three eyes had intraoperative posterior dislocation of the DMEK graft into the vitreous cavity, two of these were aphakic and one had an unstable PCIOL. Postoperatively, one graft had a total detachment and required repeat keratoplasty for primary failure, two grafts had visually significant partial detachment and needed rebubbling. Three patients developed high intraocular pressure (IOP) and one required an urgent glaucoma drainage device 1-month post-DMEK. The mean corrected distance visual acuity was 0.81 ± 0.42 logMAR preoperatively, and postoperatively was 0.6 ± 0.51 at 3 months (p = 0.414); 0.69 ± 0.81 at 6 months (p = 0.684); and 0.7 ± 0.8 at 12 months (p = 0.658).

CONCLUSIONS

DMEK in vitrectomized eyes has unique challenges that necessitate careful preoperative planning. We observed a significant proportion of dislocated grafts in vitrectomized eyes with either unstable IOL or aphakic. Moreover, vitrectomized eyes with secondary glaucoma may be particularly vulnerable to uncontrolled IOP postoperatively and close monitoring is essential to prevent worsening of visual acuity. We recommend that DMEK may not be a feasible option in eyes that are prone to collapse, in particular aphakic vitrectomized eyes, as opposed to DSAEK or penetrating keratoplasty.

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.

Outcomes of rebubbling for graft detachment after Descemet's stripping endothelial keratoplasty or Descemet's stripping automated endothelial keratoplasty

Purpose

To study the outcomes of rebubbling for graft detachment after Descemet's stripping endothelial keratoplasty (DSEK) or Descemet's stripping automated endothelial keratoplasty (DSAEK).

Methods

From 2260 eyes that underwent DSEK or DSAEK from July 2008 to June 2015, 80 eyes of 80 patients developed graft detachment and were retrospectively reviewed. Host-related, surgery-related and donor-related factors that have a bearing on graft adhesion were looked at retrospectively, and eventual outcomes after rebubbling procedure were studied.

Results

Successful attachment was observed in 77 (96.25%) eyes and clear grafts were achieved in 55 (68.75%) eyes, while 25 (31.25%) eyes had graft failure. The uncorrected and best-corrected distance visual acuities significantly improved from 1 month to 3 months post-operatively and remained stable till 12 months of follow-up. Three lenticules that failed to attach with the first rebubbling procedure underwent a second rebubbling, two underwent a repeat DSEK with good outcomes and four underwent penetrating keratoplasty. On evaluating possible risk factors for graft failure, lower donor endothelial cell density was found to be a significant factor (P = 0.03). The median graft survival following rebubbling was 30 months.

Conclusion

Rebubbling procedure in detached grafts after DSEK or DSAEK can reattach the lenticule in 96% of eyes in immediate post-operative period and the majority of the grafts remained clear on long-term follow-up with a median graft survival period of 2.5 years.

Repeat keratoplasty in failed Descemet stripping automated endothelial keratoplasty

Purpose:

To evaluate the clinical factors associated with repeat Descemet stripping automated endothelial keratoplasty (DSAEK) or penetrating keratoplasty (PKP) in cases of failed DSAEK.

Methods:

Retrospective observational study of cases with failed DSAEK admitted to our center for a repeat keratoplasty over 5 years (January 2013–Decemeber 2017) was undertaken. Demographic and perioperative details of all cases and type of repeat keratoplasty were recorded. Logistic regression analysis was performed to analyze the factors affecting the type of repeat keratoplasty.

Results:

A total of 94 eyes with failed DSAEK were evaluated. Repeat DSAEK was performed in 66% and PKP in 34% of cases. Significantly increased odds for requiring PKP were observed in association with stromal scarring [odds ratio (OR) = 2.9, P = 0.018)], trainee surgeons (OR = 4.05, P = 0.008), intraoperative complications (OR = 4.58, P = 0.003), scleral fixated intraocular lens or anterior chamber intraocular lens in situ (OR = 33.8, P < 0.001), secondary glaucoma (OR = 3.02, P = 0.015), peripheral anterior synechiae (OR = 8.6, P < 0.001), preoperative corneal thickness (OR = 1.01, P < 0001), time to primary surgery (OR = 1.03, P = 0.03), post-DSAEK host thickness (OR = 1.01, P < 0.001), and time interval from graft failure to regraft (OR = 1.18, P < 0.001). All eyes with congenital hereditary endothelial dystrophy, bee-sting-induced corneal decompensation, Axenfeld-Rieger syndrome, and multiple failed grafts underwent secondary PKP. All cases (nine eyes) that required surgical intervention for secondary glaucoma underwent secondary PKP (P < 0.001).

Conclusion:

Repeat DSAEK is feasible in up to two-third of cases of failed DSAEK. A PKP is required in one-third of cases, and various preoperative, intraoperative and postoperative factors are associated with unsuitability for repeat DSAEK.

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.

Descemet Stripping Endothelial Keratoplasty in Pediatric Patients with Congenital Hereditary Endothelial Dystrophy

PURPOSE

To report the long-term outcomes of Descemet stripping endothelial keratoplasty (DSEK) with suture-assisted donor lenticule insertion performed in different age groups for pediatric patients with congenital hereditary endothelial dystrophy (CHED).

DESIGN

Retrospective case series.

METHODS

Pediatric patients with CHED who underwent DSEK from January 2010 to January 2016 were enrolled. Patients were divided into 2 groups according to their ages: the infant group and the child group. Long-term clinical outcomes and complications were compared.

RESULTS

Thirty eyes of 16 patients were included: 19 eyes (10 patients) in the child group and 11 eyes (6 patients) in the infant group. The average duration of follow-up was 4.08 ± 1.90 years (range 2.5-8.5 years). Corneal transparency scores of the 2 groups on postoperative day 7 were not statistically different. The average postoperative best-corrected visual acuity (BCVA) in the infant group (logMAR 0.32 ± 0.11) was better than that in the child group (logMAR 0.54 ± 0.20; (P = .01). Thirty-three percent of cases in the child group and 86% of cases in the infant group had postoperative BCVA achieved or better than logMAR 0.4. Average endothelial cell loss in the child group was 31.21% ± 9.17%. Lenticule detachment occurred in 3 cases in the child group.

CONCLUSIONS

Improved visual outcomes could be achieved in infant patients with CHED after DSEK without significant complications. Suture-assisted donor lenticule insertion techniques, Descemet membrane stripping, and postoperative sedation are advocated technical points.

Functional outcome of repeat Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following graft failure after primary DMEK

Purpose

To evaluate if repeat Descemet membrane endothelial keratoplasty (DMEK) is appropriate to achieve functional improvements in patients with corneal decompensation from secondary graft failure after primary DMEK.

Methods

This is a retrospective monocentric cohort study including 13 eyes of 13 patients with repeat DMEK for corneal decompensation following primary DMEK. Eyes with primary DMEK only and comparable preoperative corrected distance visual acuity (CDVA) served as control. Main outcome parameter was CDVA. Secondary outcome measures were central corneal thickness (CCT), endothelial cell density, and rebubbling rate (RR).

Results

The average time interval (±SD) between primary and secondary DMEK was 12.5±6 months. Preoperative CDVA (logMAR) was 1.97±0.90 in the repeat DMEK group and 1.38±0.92 in the primary DMEK group. At 6 months, both groups showed significant improvement in visual acuity (repeat DMEK group, 0.49±0.35, P<0.01 and primary DMEK group, 0.40±0.36, P<0.01). CDVA did not differ significantly between both groups at all time points examined (1, 3, and 6 months postoperatively). Mean CCT values at 3 and 6 months postoperatively did not differ significantly between the two groups (P>0.05). The RR was 23% (n=3) in both groups.

Conclusion

Repeat DMEK is a useful therapeutic approach in the setting of corneal decompensation following primary DMEK. Functional results of repeat DMEK, visual acuity in particular, are comparable to patients with single DMEK only.

Clinical outcome of Descemet stripping automated endothelial keratoplasty in 18 cases with iridocorneal endothelial syndrome

PurposeTo evaluate the clinical outcome of Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with iridocorneal endothelial (ICE) syndrome.Patients and methodsA retrospective case series study was conducted. Eighteen consecutive Chinese patients with 20 DSAEK grafts were enrolled. Participants were evaluated by anterior segment optical coherence tomography and confocal microscopy. Postoperative complications, graft survival, endothelial cell counts, corneal thickness, and anterior chamber depth were analysed. A Log-rank test in a Kaplan-Meier analysis and a Cox proportional hazard regression were used to analyse potential risk factors of graft failure.ResultsThe mean follow-up duration was 19.0±8.6 months. The donors' endothelial cell density (ECD) (cells/mm²) values at 1, 3, 6, 12, 18, and 24 months were 3342.2±287.0, 1897.6±745.4, 1793.6±755.7, 1618.1±604.3, 1421.9±650.8, 1265.1±844.1, and 1148.2±1217.8, respectively. Eleven of the 20 grafts exhibited secondary graft failure, with a mean estimated graft survival of 23.4 months. Immediate postoperative complications (air bubble ventilation for elevated intraocular pressure or rebubbling for graft detachment) were more common in eyes exhibiting graft failure (P=0.040). Postkeratoplasty glaucoma surgery emerged as a risk factor of graft failure, with a hazard ratio of 5.174. Eyes with a poor prognosis showed statistically greater central corneal thickness at 1 month, greater graft thickness at 3 months, and a shallower anterior chamber at 6 and 12 months.ConclusionsThe long-term outcome of DSAEK in eyes with ICE syndrome is relatively poor. Immediate postoperative complications, postkeratoplasty glaucoma surgery, thicker corneal parameters, and a shallow anterior chamber were all associated with graft failure.

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.

Textural interface opacity after Descemet-stripping automated endothelial keratoplasty

PURPOSE

To describe cases of interface haze, also known as textural interface opacity, after Descemet-stripping automated endothelial keratoplasty (DSAEK).

SETTING

Department of Cornea, External Disease, and Refractive Surgery Service, Duke Eye Center, Durham, North Carolina, USA.

DESIGN

Retrospective case series.

METHODS

Patients' clinical and demographic characteristics, cornea donor information, surgical technique, histopathology, and anterior segment optical coherence tomography (OCT) were reviewed retrospectively and clinical outcomes reported.

RESULTS

The interface haze that developed after DSAEK comprised 2 types of textural interface opacity; that is, total (11 cases) and partial (3 cases). The time of onset of textural interface opacity ranged from 1 day to 7 weeks postoperatively. Although most patients with textural interface opacity showed improvement, with a corrected distance visual acuity better than 20/50, 3 had persistent decreased visual acuity and required repeat DSAEK. Seven eyes had concurrent phacoemulsification with intraocular lens implantation and DSAEK. The corneal graft was inserted with an Endoserter device in 11 eyes, an insertion forceps in 2 eyes, and a cystotome needle in 1 eye. Histopathology of the grafts of eyes that required repeat DSAEK showed no inflammation, no foreign-body deposit, and no fibrosis. Anterior segment OCT showed increased hyperreflectivity in the interface.

CONCLUSIONS

Although the etiology of textural interface opacity is unclear, it may be related to retained ophthalmic viscosurgical device (OVD) or an adhesive property of the OVD used during the surgery. Although most cases resolve with time, repeat DSAEK may be an effective treatment for refractory cases.

FINANCIAL DISCLOSURE

Dr. Kim is a consultant to Ocular Systems, Inc. No other author has a financial or proprietary interest in any material or method mentioned.

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.

Epithelial Downgrowth after Intraocular Surgery Treated with Intracameral 5-Fluorouracil

Purpose. To present the clinical and histopathologic correlation of two cases of epithelial downgrowth (EDG) after prior intraocular surgery. Methods. Observational case reports. Results. We present two cases of EDG occurring after intraocular surgery. In both cases, after two anterior chamber injections of 5-fluorouracil (5FU), the area of EDG initially regressed. In Case 1, a limited area of EDG eventually recurred, and penetrating keratoplasty with cryotherapy was curative. In Case 2, subsequent corneal edema required Descemet-stripping automated endothelial keratoplasty, and the patient remained clinically free of EDG without further treatment. Conclusion. Intracameral 5FU may have a role in the treatment of EDG after intraocular surgery, though its precise utilization and impact remain to be defined.

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.

Etiopathogenesis and therapy of epithelial ingrowth after Descemet's stripping automated endothelial keratoplasty

Descemet's stripping endothelial keratoplasty is an emerging technique finalized to treat endothelial dysfunction replacing only the pathological portion of cornea. The advent of any new technique puts us in front of new complications. The epithelial ingrowth is a well-known complication already studied in case of ocular trauma and more recently in refractive surgery. This job analyzed the potential etiopathogenesis of epithelial ingrowth after DSAEK, reviewing the cases described in literature, and suggests the potential therapy.

The role of postoperative positioning after DSAEK in preventing graft dislocation

PURPOSE

The aim of the study was to evaluate the importance of immediate postoperative supine patient positioning after Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

Forty eyes from 40 patients who underwent DSAEK were randomized into two groups: 20 patients sat in a chair for 2 hr postoperatively (group 1), and 20 patients were placed in a supine position (group 2) for the same time interval. At the end of surgery, the anterior chamber was fully filled with air, aiming at an intraocular pressure (IOP) of approximately 20 mmHg. The dislocation rate in the two groups was registered. IOP was measured 2 hr postoperatively and compared with endothelial cell loss at 6 months.

RESULTS

There was no statistically significant difference in the dislocation rate between the two groups (p = 0.548): two patients (10%) in group 1 and one patient (5%) in group 2. Endothelial cell loss at 6 months was 29.6% and 29.7% in group 1 and 2, respectively. There was no correlation between the IOP 2 hr after surgery and endothelial cell loss at 6 months (p = 0.741).

CONCLUSION

Supine positioning does not seem to be of crucial importance in avoiding graft dislocation in DSAEK when the anterior chamber is fully filled with air for 2 hr postoperatively.

Clinicopathologic correlation of textural interface opacities in descemet stripping automated endothelial keratoplasty: a case study

PURPOSE

The aim of this study was to describe the clinicopathologic correlation of textural interface opacities (TIOs) in a Descemet stripping automated endothelial keratoplasty (DSAEK) donor button after its removal.

METHODS

A 75-year-old woman underwent combined phacoemulsification with intraocular lens placement and DSAEK in her right eye. She had TIOs 1 week postoperatively and continued to have poor visual acuity 8 months postoperatively. The original DSAEK graft was removed, and a repeat DSAEK procedure with a new donor disc was performed. A control corneal button was obtained from a 79-year-old woman who suffered chronic rejection and had a failed DSAEK. Both corneal specimens were sent for light and electron microscopy.

RESULTS

Light microscopy of the donor tissue from the patient with TIOs showed stromal irregularities projecting from the cut anterior surface and the expected decrease in the endothelial cell density associated with the procedure and with artifacts. Electron microscopy examination showed irregular collagen fibrils of varying lengths at the stromal surface. Light and electron microscopy examination of the donor tissue from the control patient showed a smooth anterior stromal surface without projecting collagen fibrils.

CONCLUSIONS

The histopathology of the endothelial disc from the patient with TIOs demonstrated variably irregular lamellae that extended from the anterior donor corneal stromal surface. These extending lamellae were absent on the anterior stromal surface of the control corneal disc, suggesting that they are one possible cause of TIOs and the subsequent suboptimal best-corrected visual acuity and quality of vision experienced by a subset of DSAEK-operated patients.

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.

Visual outcome and histological findings following femtosecond laser-assisted versus microkeratome-assisted DSAEK

BACKGROUND

The aim of this study was to compare the visual outcome of femtosecond laser-assisted Descemet stripping automated endothelial keratoplasty (DSAEK) to microkeratome-assisted DSAEK as well as to contrast precut versus surgeon-cut grafts. Histologic characterization of failed DSAEK grafts was performed in order to correlate ultrastructural changes with graft failures.

METHODS

In this case control study, 47 cases of DSAEK were investigated in terms of visual acuity, keratometric astigmatism, spherical equivalent, endothelial cell count, and postoperative complications. We formed three groups: the femtosecondlaser-assisted DSAEK with precut grafts, the microkeratome-assisted DSAEK with precut and with surgeon-cut grafts. Mean follow-up was 6 months. In the case of graft failure, penetrating keratoplasty was performed, and the excised corneal buttons were investigated by light and electron microscopy.

RESULTS

Microkeratome-assisted DSAEK lead to better visual outcome than femtosecond laser-assisted DSAEK. Keratometric astigmatism, spherical equivalent and endothelial cell count did not differ significantly between both methods. Precut and surgeon-cut grafts in microkeratome-assisted DSAEK did not show any significant difference regarding all upraised parameters. No definite histological correlate for graft failure following femtosecond laser-assisted DSAEK was found.

CONCLUSIONS

Femtosecond laser-assisted DSAEK is not the method of choice, and needs further technical improvement. However, failed femtosecondlaser-assisted DSAEK grafts did not show significant histological changes related to the technique to explain reduced visual acuity. In microkeratome-assisted DSAEK, the preparation time point of the graft does not seem to influence the visual and optical outcome.

Lamellar corneal transplantation

Penetrating keratoplasty (PK) has been the gold standard for the surgical treatment of most corneal pathologies; lamellar keratoplasty that only replaces the diseased corneal layers has recently evolved as an alternative, however. Innovations in surgical technique and instrumentation provide visual outcomes comparable to PK. We review the indications and outcomes of various techniques of anterior lamellar surgery developed to treat stromal disorders. Similarly, we discuss posterior lamellar keratoplasty techniques such as Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty. Posterior lamellar keratoplasty provides faster visual rehabilitation than PK in cases of Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. In addition, for medically unresponsive infectious keratitis, therapeutic anterior lamellar keratoplasty yields similar graft survival to PK without an increased risk of disease recurrence.

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.

Ophthalmic transplantology: anterior segment of the eye - part I

Background

Transplantology is a quickly developing field of ophthalmology. It currently is able to treat many inherited, degenerative, inflammatory, traumatic, and cancerous diseases. This review outlines recent concepts and methods of treating ocular diseases with tissue and cell grafts. Ocular transplants related to the anterior part of the eye, including the conjunctiva and the cornea, are reviewed in Part 1.

Material/Methods

The scientific literature dated from January 2005 to July 2011 was thoroughly searched using Medline and PubMed. Publications dated 2009, 2010, and 2011 were analyzed in detail. Search terms were as follows: auto-, homo-, heterologous transplantation, eyeball, ocular adnexa, anterior segment of the eye, cornea, lamellar keratoplasty, stem cells, cultured cells. Further data were found at the website of the Eye Bank Association of America.

Results

Nearly all tissues of the anterior segment of the eye (the conjunctiva, sclera, eye muscles, and cornea) are transplanted. Because of the recent significant progress in the field, cornea transplantation was analyzed in more detail, specifically procedures such as limbus grafts and anterior and posterior lamellar keratoplasty. Indications, advantages, and drawbacks of the transplant techniques were also reviewed.

Conclusions

Recent progress in the field of cornea transplants allows treatment at the level of the endothelium and the use of cultured limbal epithelial stem cell grafts. However, compared with previous techniques, modern and multilayered transplant techniques of the cornea require much more expertise and longer training of the surgeon, as well as expensive and technologically advanced equipment. The availability of donor tissue is still the main limitation affecting all transplants. Therefore, cell culturing techniques such as stem cells, as well as artificial cornea projects, seem to be very promising.

Chandelier illumination for use during descemet stripping automated endothelial keratoplasty in patients with advanced bullous keratopathy

We demonstrate a technique that uses chandelier illumination during Descemet stripping automated endothelial keratoplasty (DSAEK) in cases of severe bullous keratopathy. A chandelier illumination fiber inserted through the corneal side port provides sclerotic scattering-like illumination from the sclerocorneal margin and endoillumination from the anterior chamber, resulting in excellent visibility for Descemet stripping and intraocular manipulation without obstruction from a hazy cornea. In cases complicated by dense cataract, the chandelier fiber can be inserted transconjunctivally into the pars plana, providing sufficient retroillumination to perform phacoemulsification with intraocular lens implantation combined with Descemet stripping for a DSAEK triple procedure. Because of the powerful illumination and hands-free nature of the chandelier fiber, the Descemet membrane can be visualized clearly and stripped as 1 sheet without inadvertent complications. We have developed a new 25-gauge illuminated anterior chamber maintainer comprising a 25-gauge infusion cannula through which a 29-gauge chandelier fiber probe passes. Because of the resulting bright illumination and adequate irrigation flow, excellent visibility with stable anterior chamber maintenance can be concurrently obtained for Descemet stripping, endothelial graft insertion, and subsequent intraocular manipulations without the need for biological staining or ophthalmic viscosurgical products, even in patients with severe corneal haze. This technique and new device facilitates safe and simple intraocular manipulation during DSAEK and encourages surgeons to perform DSAEK in challenging cases.

Donor and surgical risk factors for primary graft failure following Descemet's stripping automated endothelial keratoplasty in Asian eyes

Background

Descemet’s stripping automated endothelial keratoplasty (DSAEK) has been shown to have superior refractive and visual results compared with penetrating keratoplasty, but higher rates of primary graft failure (PGF). This paper presents donor and surgical risk factors for PGF in DSAEK cases in Asian eyes.

Design

Retrospective case-control study.

Participants

All consecutive patients who underwent DSAEK at a tertiary referral teaching hospital from March 2006–December 2008.

Methods

Donor details analyzed were: age of donor, cause of donor death, death to harvesting time, donor storage time, distribution distance of tissue, preoperative endothelial cell count. Surgical factors analyzed were: donor diameter, donor thickness, and method of donor insertion. These risk factors in cases of PGF were compared with patients with successful DSAEK as the control group.

Main outcome measure

PGF.

Results

A total of 124 DSAEK procedures were performed. Six DSAEK procedures (five eyes of five patients; one eye with two failures) resulted in PGF (4.8%). Significant risk factors were found for PGF to include graft insertion using a folding technique (odds ratio [OR], 34.03; 95% confidence interval [CI], 3.75–314.32; P = 0.0017) and a small donor diameter (OR, 39.94; 95% CI, 2.18–732.17; P = 0.013).

Conclusion

The results of this study suggest that in Asian eyes with shallow anterior chambers, surgical trauma relating to the technique of donor insertion, and the use of a small donor are major risk factors for PGF following DSAEK.

Corneoscleral block excision grafts: indications, techniques, and outcomes

PURPOSE

The purpose of this article is to discuss the indications, techniques, and outcomes for corneoscleral grafts in sight-threatening ocular disease.

METHODS

We conducted a single-center review of 12 medical records of patients who underwent corneoscleral grafts by a single surgeon (R.K.F.) from 1983 through 2004.

RESULTS

The 4 primary indications for undergoing a corneoscleral graft included infection, anterior chamber cyst, epithelial downgrowth, and invasive squamous cell carcinoma. The surgical technique involved en bloc excision of the lesion followed by placement of cadaveric corneoscleral tissue to reapproximate the original structures in the region. The surgical technique was modified to suit the individual indication and degree of involvement. Visual acuity, recurrence, complications, and time to rehabilitation are discussed. Histopathologic evaluation for each case was performed. Best-corrected visual acuity improved in 3 of 12 eyes. Vision of 20/50 or better was maintained in 5 of 12 eyes, and a visual acuity between 20/60 and 20/300 was achieved in 5 of 12 eyes. One patient with epithelial downgrowth had progression to phthisis bulbi, and 1 patient with squamous cell carcinoma experienced recurrence of the primary disease process resulting in enucleation.

CONCLUSIONS

Patients undergoing placement of large corneoscleral grafts have a guarded prognosis; however, this extensive, technically difficult, surgical intervention may allow patients to preserve and/or improve their visual function.

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).

Histopathological findings of failed grafts following Descemet's stripping automated endothelial keratoplasty (DSAEK)

PURPOSE

To study the histopathological findings of the early cases of failed DSAEK grafts and to analyze the causes of graft failure.

METHODS

Retrospective study of 13 failed DSAEK grafts (four grafts submitted alone with no host cornea) of 12 patients. The histopathologic features are correlated with the clinical and operative findings.

RESULTS

Significant attenuation of the endothelial cells found in 10/13 cases (77%), retained recipient Descemet's membrane in 7/13 (54%), variability of graft thickness in 5/13 (38%) and two of these had stromal irregularity. Retrocorneal fibrous membrane along the donor's Descemet's membrane was found in 4/13 (31%) resulting in endothelial detachment in one case. Eight of the nine host cornea-graft specimens were found to have: total graft-cornea detachment (in one), subtotal in four and partial (⩽50% of graft length) in three. The detached flaps showed infection at the interface of the graft-host cornea in two, epithelial ingrowth and fibrous proliferation along the anterior stromal surface of the graft (one case each). An additional histopathological finding was secondary amyloid deposition within the host stroma (in one).

CONCLUSION

Irregular or thick graft, graft-host interface fibrous/epithelial ingrowth, and infection all predispose to DSAEK failures related to graft detachment. Endothelial cells attenuation and retrocorneal fibrous membrane are major causes for primary graft failure.

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.

Clinicopathologic findings in failed descemet stripping automated endothelial keratoplasty

OBJECTIVE

To evaluate the clinical features of and histologic findings from failed Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

This retrospective observational case series evaluated 47 consecutive corneal specimens from 42 patients who underwent either penetrating keratoplasty or repeated DSAEK for failed DSAEK. Clinical information was obtained for the cases. Sections of the specimens were examined using light microscopy. Immunohistochemical staining was performed for cytokeratins AE1/AE3 and for the myogenic marker smooth-muscle actin when indicated. Transmission electron microscopic examination was performed in some cases.

RESULTS

Graft survival ranged from 0.5 to 34 months. Histologic examination showed that 94% of the specimens (44 of 47) had endothelial cell loss. Residual host Descemet membrane (19%; 9 of 47), fibrocellular tissue (19%; 9 of 47), epithelial implantation (15%; 7 of 47), and fungal infection (4%; 2 of 47) were also identified. Immunohistochemical stains were positive for AE1/AE3 in the epithelial implantations and for smooth-muscle actin in cells in the fibrocellular proliferations.

CONCLUSIONS

The principal cause of failed DSAEK is endothelial cell loss. Residual host Descemet membrane, fibrocellular tissue at the edge of the lenticule, and epithelial implantation are common histologic findings. Fungal infection may occur in the setting of DSAEK.

Failed descemet-stripping automated endothelial keratoplasty grafts: a clinicopathologic analysis

PURPOSE

To describe the clinicopathologic findings in failed Descemet-stripping automated endothelial keratoplasty (DSAEK) grafts.

DESIGN

Retrospective, interventional case series.

METHODS

SETTING

New York Eye and Ear Infirmary.

STUDY POPULATION

Twenty-one patients with 22 failed DSAEK grafts treated between March 1, 2006 and February 1, 2008.

INTERVENTION

Repeat DSAEK or penetrating keratoplasty were performed in the eyes with failed grafts. All failed grafts were examined histopathologically.

MAIN OUTCOME MEASURES

Histopathologic parameters studied in failed DSAEK grafts included endothelial cell count, interface characteristics, retrocorneal membrane formation, inflammation, and immunoreactivity for herpes simplex virus type 1 (HSV-1) antigen.

RESULTS

DSAEK failure was strongly associated with postoperative lenticle dislocation. Graft failure was primary in 19 DSAEKs and secondary to rejection, eccentric trephination with epithelial ingrowth, or bacterial infection in the remaining 3. All failed grafts demonstrated endothelial hypocellularity and stromal edema. Additional findings included stromal inflammation (68%), interface fibrosis (50%), retrocorneal membrane (36%), unplanned retention of Descemet membrane (14%), immunoreactivity for HSV-1 (14%), paucicellular stroma (14%), and uneven trephination with epithelial ingrowth (5%).

CONCLUSIONS

Most DSAEK failures are secondary to endothelial cell loss. Other contributing factors include interface fibrosis, retrocorneal membrane formation, retained host Descemet membrane, uneven trephination, epithelial ingrowth, graft rejection, and infection.