Three decades of corneal transplantation: indications and patient characteristics

Review of the Literature: Surgery Indications for Fuchs' Endothelial Corneal Dystrophy

Objectives: To provide an overview of the preoperative indications for endothelial graft in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: A comprehensive database search without date restrictions was performed in PubMed. Keywords included Descemet membrane endothelial keratoplasty (DMEK), Descemet stripping automated endothelial keratoplasty (DSAEK), corneal keratoplasty, preoperative visual acuity, preoperative central corneal thickness, and densitometry. Articles aiming to describe or evaluate preoperative indications for endothelial keratoplasty were considered eligible and were included in this review. Results: The indications for surgery in FECD are disparate between the different studies. The tendency is to operate on patients earlier to obtain a better postoperative visual acuity at 1 year. The surgical decision is based on a number of arguments (visual acuity, CCT, densitometry). A preoperative visual acuity worse than 20/40 is generally considered a surgical indication for DMEK, based on current literature. Conclusions: Surgical decisions for Fuchs' dystrophy should be individualized, guided by preoperative visual acuity, corneal OCT, and advanced imaging, with future risk scores potentially refining the timing of intervention to optimize outcomes.

Associations between the incidence of Fuchs' endothelial corneal dystrophy and menopausal hormone therapy use and exposure to endogenous estrogen

OBJECTIVES

End-stage Fuchs' endothelial corneal dystrophy is a leading cause of corneal blindness, with a higher prevalence in females than in males. Few modifiable risk factors have been identified. We examined associations between menopausal hormone therapy use (never/past/current), duration of hormone therapy use, estimated lifetime exposure to endogenous estrogen, and serum estradiol with incident Fuchs' endothelial corneal dystrophy in a cohort of postmenopausal women.

STUDY DESIGN

This was a prospective analysis in the Women's Health Initiative Observational Study.

MAIN OUTCOME MEASURES

Incident cases of Fuchs' endothelial corneal dystrophy were identified from the Women's Health Initiative Observational Study baseline (1993-1998) through 2019 using Medicare claims data.

RESULTS

In 22,980 women, 1382 incident cases of Fuchs' endothelial corneal dystrophy (annualized incidence rate and 95 % confidence interval = 5.0 [4.8-5.3] cases per 1000 person-years) were identified. The adjusted hazard ratios and 95 % confidence intervals for Fuchs' endothelial corneal dystrophy were 1.02 (0.88-1.18) and 0.89 (0.79-0.997) for past and current hormone therapy use (vs. never use) at baseline, respectively. Adjusted hazard ratios (95 % confidence interval) were 0.90 (0.79-1.03) and 0.95 (0.84-1.08), p-trend = 0.36, for ≤10 and > 10 years, respectively, of hormone therapy use compared with no use; and the adjusted hazard ratio (95 % confidence interval) was 1.01 (0.88-1.15), p-trend = 0.87, for 46.7-59.0 versus 13.8-41.0 years of estimated lifetime exposure to endogenous estrogen. No statistically significant associations were observed with serum estradiol concentrations in a subset of participants.

CONCLUSIONS

In this cohort of postmenopausal women, current hormone therapy use (vs. never use) showed evidence of protection against the development of Fuchs' endothelial corneal dystrophy; however, duration of hormone therapy use, estimated lifetime exposure to endogenous estrogen, or serum estradiol concentrations were not significantly associated with a decreased risk of Fuchs' endothelial corneal dystrophy.

Five years of emergency keratoplasty at a tertiary eye hospital

PURPOSE

The aim of this study is to present the results of patients who underwent emergency keratoplasty for tectonic or therapeutic reasons.

METHODS

Medical records of 33 patients who underwent tectonic or therapeutic keratoplasty at Ege University Department of Ophthalmology between January 2019 and January 2024 were retrospectively evaluated. Demographic characteristics, ocular and systemic findings, indications of keratoplasty, size of grafts, need for re-keratoplasty, preoperative treatment modalities, need for additional surgical interventions, and prognosis of the patients were investigated.

RESULTS

During this period, 450 penetrating keratoplasty (PK) surgeries were performed and 34 (7.55%) were emergency PK (34 eyes of 33 patients). The mean age of the patients was 65.30 ± 15.40 (40-91). Female to male ratio was 18/15. 17 (50.00%) emergency PKs were performed for tectonic and 17 (50.00%) were performed for therapeutic purposes. Mean follow up time was 24.85 ± 26.62 (2-120) months. A total of 20 (58.82%) eyes required additional surgery, 9 (26.47%) of which required re-keratoplasty with different indications during follow-up. Graft rejection or failure developed in 17 (50.00%) of the eyes in an average of 12.05 (1-45) months. Evisceration was needed in 2 (5.88%) eyes.

CONCLUSION

Despite limited access to donor cornea and high complication rate, emergency keratoplasty is one of the most important options that retain ocular integrity in the treatment of corneal infections and non-traumatic corneal perforations unresponsive to conventional treatment.

Investigating the Tolerance of Corneal Endothelial Cells to Surgical Fluid Pressure Using Intact Porcine Eyes

Purpose

It remains unclear if fluid pressures used during cataract surgeries contribute to iatrogenic corneal endothelial cell (CEC) loss.

Methods

A custom experimental platform was used to pressurize the anterior chamber of explanted porcine eyes to surgical fluid pressures of 60 mm Hg or 400 mm Hg for 5 minutes or 60 mm Hg for 45 minutes (n = 8 or 9 per group). The corneal endothelia were stained with a unique combination of nucleic acid viability dyes and were imaged using fluorescence microscopy without removing the cornea from the globe. The images were analyzed using custom code to quantify acute CEC loss as a percentage of CEC injury/death (PCI). The PCI values from the surgical pressure groups were compared to sham controls perfused to physiological pressures for each surgical duration. As a positive control, a group of eyes (n = 8) was perfused with deionized water to intentionally induce CEC injury/death.

Results

No significant differences were observed in mean PCI values between any of the surgical fluid pressure groups and sham control groups, at either duration. The mean PCI of the positive control group was significantly different from all other groups, indicating that the method is able to detect CEC injury/death.

Conclusions

Our results suggest that the magnitudes of fluid pressure used over the duration of a cataract surgery do not significantly contribute to acute iatrogenic CEC loss.

Translational Relevance

Not only do the findings of this study answer a longstanding clinical question related to cataract surgery, but the platform introduced will facilitate testing how new cataract surgery devices and techniques affect CEC viability.

Crosslinking with UV-A and riboflavin in progressive keratoconus: From laboratory to clinical practice - Developments over 25 years

Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularize it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.

[Intracorneal selective stromal transplantation]

Deep anterior lamellar keratoplasty or penetrating keratoplasty are currently considered the optimal methods of surgical treatment of stromal dystrophies and corneal degeneration. Despite certain advantages and benefits of these methods, they also have significant limitations: involvement of superficial corneal layers in the surgery, need for suturing, development of post-keratoplasty astigmatism etc.

PURPOSE

This study aimed to test and describe the new method of closed sutureless keratoplasty (intracorneal selective stromal transplantation), which was indicated in isolated dystrophic and degenerative pathology of the stroma.

MATERIAL AND METHODS

Intracorneal selective stromal transplantation was performed in a 62-year-old patient with stromal degeneration and intact corneal layers between the altered stroma and the Descemet's membrane posteriorly, and the Bowman's layer anteriorly. The patient also had immature senile cataract. Corneal stroma was removed and replaced with a graft in the optical center of the lens, while the endothelium, the Descemet's membrane and the Bowman's layer remained intact.

RESULTS

The proposed technique of intracorneal selective stromal transplantation makes it possible to replace only the pathologically altered stroma through closed surgical approach, without affecting the anterior and posterior surfaces of the cornea. Best-corrected visual acuity has increased in the patient from 0.01 to 0.6, while mean endothelial cell density has not changed in the course of 24-months follow-up.

CONCLUSION

The proposed keratoplasty method can be used in patients with dystrophy or degeneration of the corneal stroma and preserved endothelial cells, intact Descemet's membrane and Bowman layer. Since the superficial corneal layers are not involved during the surgery, intracorneal selective stromal transplantation combined the advantages of both deep anterior lamellar keratoplasty and endothelial keratoplasty. The biologically favorable result in this first clinical case allows a preliminary conclusion on the technical possibility and functional effectiveness of the proposed method, but further long-term observation and more clinical cases are required.

Disparities in Access to Corneal Tissue in the Developing World

Corneal disease is a leading cause of blindness worldwide. For most blinding corneal conditions, keratoplasty is the only way of restoring sight. Unfortunately, access to corneal transplantation is widely variable, most notably due to the lack of suitable donor material. There exists significant disparity between the developed and developing world when it comes to access to cornea tissue, with supply often inversely proportional to burden of disease. The purpose of this review is to identify the current disparities in supply and demand of corneal donor tissue, understand how to access corneal tissue, and propose solutions that promote equitable care for patients with severe corneal disease.

Penetrating Keratoplasty: Indications and Graft Survival by Geographic Region

Corneal transplantation, or penetrating keratoplasty (PK), is the most common form of solid-organ transplantation performed worldwide. Here, we evaluated the indications for PK and rates of transplant survival around the world by geographic region. We conducted a literature search of PubMed, MEDLINE, and Google Scholar databases and identified 155 relevant studies from 41 countries published between 1987 and 2021. The most common indications for PK were keratoconus in Europe, Africa, the Middle East, Australia, New Zealand, and Central and South America, bullous keratopathy in North America, and corneal scarring in Asia. The overall global mean graft survival rates at 1-, 2-, 3-, 5-, and 10-years were 88.6%, 81.2%, 78.9%, 72.8%, and 61.2%, respectively. Through this systematic analysis of PK by region, we hope to bring a new perspective to the corneal transplantation literature and to potentially highlight global differences and unmet needs in patient care.

The Atypical Red Eye: A Case of Scleritis with Peripheral Ulcerative Keratitis Secondary to Granulomatosis with Polyangiitis

This report presents a rare case of scleritis with peripheral ulcerative keratitis secondary to granulomatosis with polyangiitis (GPA). A 65-year-old Caucasian male presented to a regional ophthalmology service with an atypical red eye. His immune work-up demonstrated positive anti-neutrophil cytoplasmic IgG autoantibodies (ANCA) with anti-proteinase 3 antibody (PR3) elevation. Multi-system vasculitis was discovered including lung, liver, bladder, prostate, nasal and paranasal sinuses involvement. His ocular sequelae included significant peripheral corneal thinning requiring cyanoacrylate gluing, juxtalimbal conjunctival resection, and bandage lens placement. He was treated with systemic methylprednisolone and rituximab achieving remission with ongoing prednisone and methotrexate maintenance therapy. This case demonstrates the importance of recognizing ocular manifestations of GPA as a first presentation of systemic vasculitis.

Ocular manifestations of rheumatoid arthritis

PURPOSE OF REVIEW

This article summarizes the pathophysiology of rheumatoid arthritis and common ocular manifestations that it is associated with: keratoconjunctivitis sicca, episcleritis, scleritis, and peripheral ulcerative keratitis.

RECENT FINDINGS

Newer biologic agents are being used to effectively treat rheumatoid arthritis and its ocular manifestations.

SUMMARY

The eye is a frequent extra-articular site of inflammation in patients with rheumatoid arthritis. Ocular involvement can range from more benign conditions such as keratoconjunctivitis sicca and episcleritis, to potentially vision and globe-threatening diseases like scleritis and peripheral ulcerative keratitis. Clinicians should be aware of these ophthalmic manifestations and the various treatment options that are available. Coordination between ophthalmology and rheumatology is helpful in the treatment of these patients.

Ocular Drug Delivery: Advancements and Innovations

Ocular drug delivery has been significantly advanced for not only pharmaceutical compounds, such as steroids, nonsteroidal anti-inflammatory drugs, immune modulators, antibiotics, and so forth, but also for the rapidly progressed gene therapy products. For conventional non-gene therapy drugs, appropriate surgical approaches and releasing systems are the main deliberation to achieve adequate treatment outcomes, whereas the scope of “drug delivery” for gene therapy drugs further expands to transgene construct optimization, vector selection, and vector engineering. The eye is the particularly well-suited organ as the gene therapy target, owing to multiple advantages. In this review, we will delve into three main aspects of ocular drug delivery for both conventional drugs and adeno-associated virus (AAV)-based gene therapy products: (1) the development of AAV vector systems for ocular gene therapy, (2) the innovative carriers of medication, and (3) administration routes progression.

Peripheral ulcerative keratitis

Peripheral ulcerative keratitis (PUK) is an inflammatory condition of the peripheral cornea with hallmark features of epithelial defects and stromal destruction as a result of a complex interplay of factors including host autoimmunity and the peculiar anatomic and physiologic features of the peripheral cornea and environmental factors. PUK may be the result of local or systemic causes and infectious or noninfectious causes. Arriving at a specific etiological diagnosis requires a meticulous clinical workup that may include a battery of laboratory and radiological investigations. Management by a team of internists or rheumatologists and ophthalmologists and judicious use of immunosuppressive agents may yield favorable results minimizing adverse effects. We review current clinical knowledge on the diagnosis and management of PUK.

Metabolomic Signature Discriminates Normal Human Cornea from Keratoconus-A Pilot GC/MS Study

The molecular etiology of keratoconus (KC), a pathological condition of the human cornea, remains unclear. The aim of this work was to perform profiling of metabolites and identification of features discriminating this pathology from the normal cornea. The combination of gas chromatography and mass spectrometry (GC/MS) techniques has been applied for profiling and identification of metabolites in corneal buttons from 6 healthy controls and 7 KC patients. An untargeted GC/MS-based approach allowed the detection of 377 compounds, including 46 identified unique metabolites, whose levels enabled the separation of compared groups of samples in unsupervised hierarchical cluster analysis. There were 13 identified metabolites whose levels differentiated between groups of samples. Downregulation of several carboxylic acids, fatty acids, and steroids was observed in KC when compared to the normal cornea. Metabolic pathways associated with compounds that discriminated both groups were involved in energy production, lipid metabolism, and amino acid metabolism. An observed signature may reflect cellular processes involved in the development of KC pathology, including oxidative stress and inflammation.

Two cases of perforated corneal ulcers complicating rheumatoid arthritis treated successfully by biological therapy

Background

Peripheral ulcerative keratitis (PUK) is a severe inflammatory ocular disease that can affect patients with a long history of rheumatoid arthritis (RA). The use of biotherapy has revolutionized the treatment of the RA and has provided encouraging outcomes especially in the treatment of PUK reported in few cases. In this article, we describe the case of two patients with the history of perforated corneal ulcer complicating RA treated successfully by biologic agents.

Case presentation

Case 1: A 45-year-old woman was diagnosed for over 17 years with sero-positive RA refractory to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs). She had received one cycle of Rituximab with clinical and biological failure. In July 2017, she presented an active RA flare with a painful left eye and a decreased visual acuity. Ocular examination revealed a corneal perforation in the left eye and a pre-perforation in the right eye. She received an emergency bolus of methylprednisolone 1 g/day during three consecutive days and was followed by Infliximab. After thirteen months, Infliximab was effective on the rheumatic disease and on the corneal involvement as it stopped its gradual perforation in the right eye, and stabilized corneal ulcer in the left eye.

Case 2: A 68-year-old man had been diagnosed since 2010 with sero-positive RA refractory to csDMARDs complicated in July 2017 by corneal perforation in the right eye. He was hospitalized for his ocular involvement and his active RA. He received an emergency bolus of methylprednisolone 500 mg/day during three consecutive days and was followed by Rituximab. After six months, we observed the stabilization of the right eye corneal damage and the resolution of articular symptoms.

Conclusions

Our cases suggest the efficacy of Infliximab (case 1) and Rituximab (case 2) as a treatment of this severe and destructive keratolysis of the cornea complicating an active RA allowing to plan corneal graft. This positive therapeutic response will contribute to increase literature reports of this therapy success.

Graft-size selection and anisometropia reduction in penetrating keratoplasty (PKP)

PURPOSE

To compare the amount of myopia induced by same-size donor-to-host penetrating keratoplasty with that of the amount of myopia induced by over-sized donor-to-host penetrating keratoplasty.

SETTING

Tertiary referral academic center.

DESIGN

Retrospective cohort study.

METHODS

Charts from patients who underwent penetrating keratoplasty by the same technique at Bascom Palmer Eye Institute between Nov 1, 2002, and January 1, 2006, were reviewed. The patients underwent optical penetrating keratoplasty using 12 interrupted 10-0 nylon sutures and a 12-bite continuous 10-0 nylon suture by a single surgeon (R.K.F.). The surgical technique used would be considered standard of care at most institutions. The Institutional Review Board, University of Miami Human Subjects Research Office, approved the study protocol. The donor graft was over-sized by 0.25mm in eyes when the intended final refractive target was greater than -1.00 diopters spherical equivalent (SE). The same-size donor graft was used when the intended final refractive target was less than -1.00 diopters SE. The selection of donor graft size was entirely based upon clinical parameters, meaning that the intended final refractive target was determined per each patient's fellow eye refraction, with the intention of reducing anisometropia. All patients received postoperative refraction and corneal topography. These measurements were performed at 6-8 weeks when the initial removal of sutures commenced, then at 6 months, then after completion of selective suture removal, then again at 12 months.

RESULTS

At 12 months, the over-sized group resulted in -1.35 diopters (SD = 2.25) SE of refraction, and the same-size group resulted in -0.14 diopters (SD = 2.42) SE. This approached statistical significance (p = 0.052) in comparison to -1.00 diopters spherical equivalent.

CONCLUSIONS

Using a donor graft that is over-sized by 0.25mm results in refraction of -1.00 diopters SE or more of myopia. Using a same-size donor-graft results in refraction of less than -1.00 diopters SE. Therefore, careful graft-size selection can result in a more favorable clinical outcome-namely, reduction in anisometropia-in patients undergoing penetrating keratoplasty.

Electro-spun Membranes as Scaffolds for Human Corneal Endothelial Cells

BACKGROUND

Corneal endothelial dysfunction remains the most frequent indication for corneal transplantation, limited by donor material shortage, poor long-term graft survival, or allogeneic graft rejection. Therefore, tissue-engineered endothelial grafts (TEEG) represent a promising alternative to human donor tissue. In this study, we generated electro-spun scaffolds and tested these for their suitability for human corneal endothelial cell (hCEC) cultivation.

METHODS

The polymers poly(methyl-methacrylate) (PMMA), poly(lactic-co-glycolic acid) (PLGA), and polycaprolactone (PCL) were spun with equal parameters. HCEC-12 was cultured on the scaffolds for 3 to 7 days. Scaffolds were evaluated by light microscopy, porometry, light transmission, scanning electron microscopy (SEM), live/dead staining and cell viability assay.

RESULTS

Electro-spun fibers from PMMA (2.99 ± 0.24 µm) showed significantly higher diameters than PCL (2.29 ± 0.11 µm; p = 0.003) and PLGA (1.84 ± 0.21 µm; p < 0.001), while fibers from PCL also showed larger diameters than those from PLGA (p = 0.002). PMMA scaffolds (26.77 ± 17.48 µm) had significantly larger interstitial spaces than those from PCL (13.30 ± 5.47 µm; p = 0.04) and PLGA (10.42 ± 6.15 µm; p = 0.002), while PCL and PLGA did not differ significantly (p = 0.26). SEM analysis revealed that only PLGA fibers preserved a normal HCEC-12 morphology. PLGA and PCL did not differ in cell number, death, or viability after 7 days of HCEC-12 cultivation. PMMA showed significantly higher cytotoxicity (p < 0.001; PLGA: 1626.2 ± 183.8 RLU; PMMA: 841.9 ± 92.7 RLU; PCL: 1580.2 ± 171.02 RLU).

CONCLUSIONS

The biodegradable PLGA and PCL electro-spun scaffolds resulted in equal biocompatibility, while PMMA showed cytotoxicity. Only PLGA preserved hCEC morphology and consequently seems to be a promising candidate for TEEG construction.

Indications and Surgical Techniques for Corneal Transplantation at a Tertiary Referral Center

Purpose

The study aimed to review the indications and techniques for corneal transplantation at a tertiary referral center over a 5-year period.

Methods

Records of patients who underwent corneal transplantation at Khalili Medical Center, Shiraz, Iran from September, 2012 to September, 2017 were reviewed.

Results

A total of 1149 eyes of 956 patients underwent corneal transplantation. The most common indication was infectious corneal ulcers (n = 296, 25.8%), followed by keratoconus (n = 243, 21.1%), bullous keratopathy (n = 219, 19.1%), failed grafts (n = 117, 10.2%), non-herpetic corneal scars (n = 113, 9.8%), corneal stromal dystrophies (n = 33, 2.9%), pellucid marginal degeneration (n = 31, 2.7%), and trauma (n = 26, 2.3%); other indications included thin descemetocele, post-herpetic corneal scar, endothelial corneal dystrophies, anterior segment dysgenesis, corneal ectasia after laser in situ keratomileusis, and corneal fibrosis. Corneal transplantation techniques included penetrating keratoplasty (PKP, n = 789, 68.7%), deep anterior lamellar keratoplasty (DALK, n = 187, 16.3%), Descemet's stripping automated endothelial keratoplasty (n = 171, 14.9%), and keratolimbal allograft (n = 2, 0.1%) in descending order. In children (aged ≤18 years), the most common indication was keratoconus (n = 32, 41.6%), and the most common technique was PKP (n = 50, 64.9%). In patients aged 19-27 years, the most common indication was keratoconus (n = 89, 64.5%), and the most common technique was PKP (n = 75, 54.4%).

Conclusion

Infectious corneal ulcer was the most common indication, and PKP was the most prevalent technique in patients undergoing corneal transplantation. DALK was an emerging alternative surgical treatment in patients with corneal disorders in which corneal endothelium is spared.

Corneal cell therapy: with iPSCs, it is no more a far-sight

Human-induced pluripotent stem cells (hiPSCs) provide a personalized approach to study conditions and diseases including those of the eye that lack appropriate animal models to facilitate the development of novel therapeutics. Corneal disease is one of the most common causes of blindness. Hence, significant efforts are made to develop novel therapeutic approaches including stem cell-derived strategies to replace the diseased or damaged corneal tissues, thus restoring the vision. The use of adult limbal stem cells in the management of corneal conditions has been clinically successful. However, its limited availability and phenotypic plasticity necessitate the need for alternative stem cell sources to manage corneal conditions. Mesenchymal and embryonic stem cell-based approaches are being explored; nevertheless, their limited differentiation potential and ethical concerns have posed a significant hurdle in its clinical use. hiPSCs have emerged to fill these technical and ethical gaps to render clinical utility. In this review, we discuss and summarize protocols that have been devised so far to direct differentiation of human pluripotent stem cells (hPSCs) to different corneal cell phenotypes. With the summarization, our review intends to facilitate an understanding which would allow developing efficient and robust protocols to obtain specific corneal cell phenotype from hPSCs for corneal disease modeling and for the clinics to treat corneal diseases and injury.

Evaluation of Corneal Biomechanical Changes After Collagen Crosslinking in Patients with Progressive Keratoconus by Ocular Response Analyzer

Objectives:

To evaluate corneal biomechanics before and after collagen crosslinking (CXL) in patients with progressive keratoconus.

Materials and Methods:

In this prospective study, CXL was performed under topical anesthesia after removal of the epithelium (epi-off technique) by applying ultraviolet A (UVA) light at a wavelength of 365 nm and power of 3 mW/cm2 or 5.4 joule/cm2. Isoosmolar 0.1% riboflavin solution was administered before and during UVA irradiation. In addition to ophthalmologic examination, ocular response analyzer measurements were performed pre- and postoperatively. Corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc), Goldmann-correlated intraocular pressure (IOPg), and central corneal thickness (CCT) were recorded.

Results:

The study included 35 eyes of 30 patients with progressive keratoconus. The mean age was 28.2±6.5 years and postoperative follow-up time was 20.2±14.7 months (range: 6-74 months). The mean CH was 8.60±1.23 mmHg preoperatively, 8.96±2.05 mmHg in the early postoperative period (1-6 months), (p=0.28) and 8.96±1.28 mmHg in the late postoperative period (10-29 months) (p=0.48). Mean CRF was 7.13±1.50 mmHg preoperatively, 8.48±2.16 mmHg in the early postoperative period (p=0.009), and 7.71±1.29 mmHg in the late postoperative period (p=0.40). Mean IOPcc was 12.78±2.34 mmHg preoperatively, 15.38±4.21 mmHg in the early postoperative period (p=0.12) and 13.68±3.61 mmHg in the late postoperative period (p=0.48). Mean IOPg was 9.56±2.73 mmHg preoperatively, 13.01±4.45 mmHg in the early postoperative period (p=0.046), and 10.86±3.47 mmHg in the late postoperative period (p=0.44). Mean CCT was 484.43±41.26 µm preoperatively, 474.16±64.74 µm in the early postoperative period (p=0.70), and 470.38±33.64 µm in late postoperative period (p=0.71).

Conclusion:

CXL is a treatment modality believed to affect corneal biomechanics in keratoconus, but the results of larger patient series with longer follow-up periods may enable a better evaluation.

Comparasion of the results of corneal topography findings in fuchs endothelial dystrophy and pseudophakic bullous keratopathy

Background: Comparison of Fuchs endothelial dystrophy and pseudophakic bullous keratopathy with the help of Scheimpflug camera combined with a Placido disk corneal topographer. Material and methods: 34 eyes of 34 patients pseudophakic bullous keratopathy (PBK) and 32 eyes of 20 patient Fuchs endothelial dystrophy (FED) have been examined by Scheimpflug camera combined with a Placido disk corneal topographer. Anterior chamber depth (ACD), anterior chamber volume (ACV), iridocorneal angle (ICA), central corneal thickness (CCT) and LogMAR best corrected visual acuity (BCVA) were compared in terms. Except for corneal edema, diseases of the eye that can impair vision (cataracts, glaucoma, retinal disease) were excluded. Results: The average age of patients in group PBK and FED were found 64.9 ± 13.9 and 66.06 ± 10.5 respectively. ACD, ACV, ICA, CCT and BCVA in PBK group 2.95 ± 0.48 mm, 202.55 ± 115.20 mm3 , 40.73 ± 10.44 derece, 742.41 ± 108.74 m and 2.06 ± 0.70 LogMAR respectively. ACD, ACV, ICA, CCT and BCVA in FED group 2.63 ± 0.64 mm, 140.75 ± 71.34 mm3 , 34.62 ± 13.58 derece, 757.37 ± 145.99 m and 1.82 ± 1.12 LogMAR respectively. Statistically significant difference between the 2 groups in terms of ACV and LogMAR BCVA was observed (p = 0.01 and p = 0.001). Between other parameters as mean age, ACD, ICA and CCT, statistically difference was not observed (p > 0.05). Conclusions: Between two groups in terms of age, ACD, ICA and CCT statistically significant difference was not significant, while in terms of ACV and BCVA LogMAR observed results showed statistically significant difference (p < 0.05).

[Practical assessment of DSAEK in the management of endothelial decompensation following penetrating keratoplasty]

PURPOSE

To report our anatomical and functional results as well as possible complications of the first six Descemet's stripping endothelial keratoplasties (DSAEK) performed in our department for endothelial decompensation after penetrating keratoplasty (PK) METHODS: This was a retrospective and observational monocentric study of six patients with DSAEK after prior PK between January 2015 and July 2016. The data collected were: demographic characteristics (age, sex), ophthalmological comorbidities, initial indication for PK, delay between PK and DSAEK. Best corrected visual acuity (BCVA) preoperatively and at 1, 3 and 6 months postoperatively were collected in Monoyer's and Parinaud scale and converted to log MAR for statistical analysis. The central cornea and graft thickness measured on OCT as well as postoperative complications were also collected.

RESULTS

Mean follow-up duration was 7.2 months [3-10]. The average time after PK was 7.7 years. The mean age of the patients was 67.5 years [32-87]. The initial indication for PK was Fuchs dystrophy (3/6), pseudophakic bullous keratopathy (1/6), corneal laceration (1/6) and other corneal dystrophy (1/6). The authors report one case a combined phaco-DSAEK surgery. The complications observed were: an early graft detachment treated by an additional air bubble injection (1/6) and cystoid macular edema in one other case. The average central corneal thickness decreased from 780μm at day 7 postoperatively to 656μm at 6 months. The average thickness of the graft decreased from 154μm at day 7 to 122μm at 6 months. The mean preoperative BCVA was 1.52 log MAR [1.0-1.7], compared to the mean postoperative BCVA which was 1.5 log MAR [1.1-2.3] at 1 month, 1.15 log MAR [0.5-1.7] at 3 months and 1.1 log MAR [0.7-1.7] at 6 months (data available for 4 patients at 6 months). The recovery of visual acuity was limited in 2 cases, despite corneal clarity restored in all our patients.

DISCUSSION

Our results can be compared to those described in literature. As more penetrating keratoplasty grafts reach the end of their lives, this will allow for more powerful studies.

CONCLUSION

DSAEK on eyes previously treated with PK is a good alternative to a new PK in the case of endothelial decompensation of the graft. The possibility of a posterior lamellar graft allows for faster visual recovery, with preservation of the anterior corneal power and a lower rate of complications.

Changing Indications in Penetrating Keratoplasty: A Systematic Review of 34 Years of Global Reporting

BACKGROUND

Penetrating keratoplasty (PK) ranks among the oldest and most common kinds of human tissue transplantation. Based on the hypothesis that reported indications for PK significantly vary between global regions and over time, the present systematic review aimed to provide a thorough overview of global PK indications as reported in peer-reviewed manuscripts.

METHODS

A literature search of PubMed and MEDLINE was conducted to retrieve articles published from January 1980 to May 2014. Indications for PK within 7 global regions were compared using a modified classification system for PK indications and analyzed via multivariate regression.

RESULTS

A total of 141 publications from 37 countries were included, recording 180 865 PK cases. Postcataract surgery edema was the predominant indication in North America (28.0%) and ranked second in Europe (20.6%), Australia (21.1%), the Middle East (13.6%), Asia (15.5%), and South America (18.6%). Keratoconus was the leading indication in Europe (24.2%), Australia (33.2%), the Middle East (32.8%), Africa (32.4%), and South America (22.8%). It ranked third in North America (14.2%). Keratitis was the primary indication in Asia (32.3%). Fuchs endothelial corneal dystrophy was the fourth most common indication in North America (12.9%) and Europe (10.2%) and fifth in South America (3.8%). Multivariate analysis supported these results and revealed individual regional changes over time.

CONCLUSIONS

Systematic analysis reveals characteristic chronological and regional differences in reported global PK indications. Leading reported indications for PK between 1980 and 2014 were keratoconus (Europe, Australia, the Middle East, Africa, and South America), pseudophakic bullous keratopathy/aphakic bullous keratopathy (North America), and keratitis (Asia).

Corneal Biomechanical Properties After Penetrating Keratoplasty or Deep Anterior Lamellar Keratoplasty Using the Ocular Response Analyzer: A Meta-Analysis

PURPOSE

To evaluate the corneal biomechanical properties of patients who have undergone penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty (DALK) using the ocular response analyzer.

METHODS

Stata 13.0 SE was used for this meta-analysis. Studies in the literature that focused on corneal hysteresis (CH) or corneal resistance factor (CRF) after PK or DALK were retrieved by searching PubMed, Embase, Ovid, and Cochrane databases. We present the results as weighted mean difference (WMD) with a corresponding 95% confidence interval (CI).

RESULTS

Eight studies with a total of 750 eyes were included in the post-PK versus control group, and 4 studies with a total of 218 eyes were included in the post-DALK versus control group. The pooled results showed that CH and CRF were significantly reduced (P < 0.00001) for patients who have undergone PK (WMD = -1.16, 95% CI: -1.73 to -0.60 and WMD = -1.00, 95% CI: -1.61 to -0.40). No significant differences were found in both CH and CRF for patients who have undergone DALK (WMD = -0.27, 95% CI: -0.64 to -0.09 and WMD = -0.15, 95% CI: -0.53 to 0.23).

CONCLUSIONS

This meta-analysis suggested that both CH and CRF had better recovery after corneal transplantation with DALK than PK.

[Visual outcomes after Descemet's membrane endothelial keratoplasty]

OBJECTIVES

Evaluation and monitoring at 6 months after Descemet's membrane endothelial keratoplasty (DMEK) in patients with Fuchs endothelial dystrophy and study of factors influencing visual rehabilitation and postoperative quality of life.

METHODS

Prospective, consecutive, interventional study of 35 eyes of 32 patients with Fuchs endothelial dystrophy who underwent surgery from February 2015 to February 2016 by DMEK. Measurement at D10, M1, M3, M6 of visual acuity, graft endothelial cell density, pachymetry, and intraocular pressure, and performance at M6 of aberrometry, macular OCT and a quality of life survey (NEI-VFQ-25). Post-DMEK aberrations are compared to those from control patients selected for refractive surgery.

RESULTS

Visual acuity improvement at 6 months was statistically significant (P<0.0001), as well as pachymetry decrease (P<0.0001), endothelial cell loss (P<0.0001) and intraocular pressure increase (P=0.003). We observed a statistically significant difference between post-DMEK aberrations and those of control subjects for all aberrations from 2nd to 5th order. There were no postoperative correlations between visual acuity, pachymetry, intraocular pressure, or endothelial cell loss. The global quality of life score at six months was 87, corresponding to a good quality of life. We did not find a link between the global NEI-VFQ-25 score and visual acuity or visual aberrations. Ninety percent of patients surveyed reported a postoperative general improvement in quality of life at M6.

CONCLUSION

DMEK provides good visual rehabilitation and an improvement in quality of life for patients with Fuchs endothelial dystrophy. Higher order optical aberrations in these patients, although higher than in a healthy population, are negligible and have no impact on quality of vision or postoperative quality of life.

The effect of air, SF6 and C3F8 on immortalized human corneal endothelial cells

PURPOSE

While anterior chamber air bubbles aid attachment during posterior lamellar surgery only for few days, these periods can be prolonged with gases in non-expanding concentrations. To test the effects of different gas compositions on immortalized human corneal endothelial cells (HCEC-12), we utilized Transwell inserts with semipermeable membranes as an artificial anterior chamber model.

METHODS

Human corneal endothelial cells (HCEC-12) were cultured on Transwell inserts for 24 hr, then flipped, burdened and sunk with titanium rings in medium (M1), as well as filled with 2 ml of air (A), 20% sulphur hexafluoride (SF6) (S), or 12% C3F8 (C). After gas exposition for 24, 48 and 120 hr, cells were evaluated by live/dead staining, cell viability assay and Ki67 immunohistochemistry.

RESULTS

Proliferation was significantly reduced (Ki67-positive fraction; M1, 14.8 ± 2.0%; A, 7.9 ± 1.4%; S, 8.1 ± 1.3%; C, 9.9 ± 2.3%; p-values; A, S, C versus M1 < 0.01), the total cell number decreased and the percentage of dead cells increased under gas exposition, independently of the type of gas (120 hr cell count/2.25 cm² : M1 = 660.8 ± 57.0 cells; A = 125.5 ± 17.4 cells, S = 123.5 ± 17.0 cells, C = 118.8 ± 16.6 cells; p-value: M versus A/S/C < 0.001; 120 hr dead cells: M = 2.6 ± 1.0%, A = 8.4 ± 2.7%, S = 9.5 ± 3.2%, C = 11.3 ± 3.1%; p-value: M1 versus A/S/C < 0.01). Medium (M1)-control also proved significantly higher cell viability values in comparison with the gases, which did not differ significantly among them (120 hr luminescence: M1 = 1752.2 ± 91.4, A = 433.0 ± 30.3, S = 507.8 ± 23.3, C = 523.8 ± 20.3; p-value: M1 versus A/S/C < 0.01).

CONCLUSIONS

Gas exposition led to a reduction in proliferation and an increase in cell death in HCEC-12, independently of the gas composition.

Emergency corneal grafting in the UK: a 6-year analysis of the UK Transplant Registry

BACKGROUND

Corneal graft (CG) surgery is the most common and successful tissue transplant worldwide. A small and important group of patients are operated in emergency situations, typically to save a perforated eye. Our knowledge of the indications and outcomes of emergency corneal graft (eCG) is limited.

METHODS

Retrospective, multifactorial analysis of all CGs registered by the UK Transplant Service from April 1999 to March 2005.

RESULTS

A total of 12 976 CGs were performed. 1330 (11.4%) were eCGs including 433 regrafts. Actual perforation occurred in 876 (65.9%) patients. 420 (31.5%) grafts were for tectonic purposes alone and 217 (16.3%) were also grafted for visual rehabilitation. The main diagnostic categories were infection (39.4%), non-infectious ulcerative keratitis (32.2%) and other causes (ectasias, previous ocular surgery, injury, dystrophies and opacification). Graft survival of first eCG at 1, 2 and 5 years was 78%, 66% and 47%, respectively. Best-corrected visual acuity of surviving grafts at 1 year was: 6/12 or better in 29.9%, 6/18 to 6/60 in 38.4%, counting finger to LP in 30.6% and NPL in 1%, with worsening of vision in only 8.7% of the patients.

CONCLUSION

This study which is the largest of its kind shows that despite the seriousness of the critical corneal pathology and the surgical challenges that it poses, the outcomes of eCG are favourable with most patients keeping their eyesight and avoiding immediate rejection. These clinical outcomes show the value of eye banking facilities that are developed to support corneal tissue supply for eCG.

A Novel Tectonic Keratoplasty with Femtosecond Laser Intrastromal Lenticule for Corneal Ulcer and Perforation

BACKGROUND

Small incision refractive lenticule extraction (SMILE) is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule (TEKIL).

METHODS

A total of twenty patients (22 eyes) were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity (BCVA). Postoperative complications throughout the study period were recorded.

RESULTS

Corneal ulcer in 14 patients (16 eyes) and corneal perforation in six patients (6 eyes) were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years (range: 16-81 years). In this study, the most causes of corneal ulcer or perforation were immunologic causes (54.5%). After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17 ± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up (t = 2.095, P = 0.052). The postoperative BCVA improved in 12 eyes (54.5%) and maintained in nine eyes (40.9%). Vision function successfully maintained in all eyes (100%). In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months after the initial surgery for the reason that the residual corneal thickness was <250 μm.

CONCLUSIONS

TEKIL seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage.

Effects of Corneal Collagen Crosslinking on Confocal Microscopic Findings and Tear Indices in Patients with Progressive Keratoconus

Background:

To evaluate any change in tear indices and confocal microscopic findings after corneal collagen crosslinking (CXL) in patients with progressive keratoconus.

Methods:

Thirty-two consecutive eyes from 23 patients having progressive keratoconus were enrolled in this prospective, interventional cohort study. The standard crosslinking surgery was performed for all patients. Visual, refractive, and topographic evaluations were done before and at 6 months after surgery. Tear function tests and confocal microscopic examination were performed before and at 1 month and 6 months after the procedure.

Results:

There was no significant change in Schirmer-1 test results and tear osmolarity at 1 month and 6 months after CXL. Using confocal microscopy, all eyes showed reduced or absent subepithelial nerve plexus. Differences in basal epithelial cell density, epithelial mean cell area, and keratocyte density in anterior and middle stroma and endothelial cell pleomorphism were all significant at 1 month and 6 months after CXL (P < 0.05). No significant change was noted in endothelial cell count and their polymegathism at 6 months follow-up. Significant improvement was noted in uncorrected visual acuity, best corrected visual acuity, flattest corneal meridian (K₂), and maximum keratometry in Pentacam (K_max) after 6 months of the procedure.

Conclusions:

While CXL would have no effect on tear indices and endothelial cell count, it can cause a significant reduction in subepithelial nerve plexus and significant alterations in epithelial cell density in the anterior and middle stroma.

Gebauer SLc Original and Moria One-Use Plus automated microkeratomes for ultrathin Descemet's stripping automated endothelial keratoplasty preparation

PURPOSE

We compared the SLc Original (SLc) and One-Use Plus (OUP) microkeratomes for ultrathin Descemet's stripping automated endothelial keratoplasty (DSAEK) lamella preparation and storage, vis-à-vis accuracy, endothelial cell loss (ECL) and lamellar surface roughness (LSR).

METHODS

Twenty-five human corneas were dissected with single-use heads of different sizes aiming for a posterior lamella (PL) thickness of 85 μm, after which they were incubated for 6 days in a 5% dextran medium. Before preparation (0 hr) and 1, 24, and 144 hr after dissection, ECL and corneal thickness (CCT) were measured by ultrasound pachymetry (USP) and optical coherence tomography (OCT). Lamellar surface roughness (LSR) was assessed by scanning electron microscopy (SEM) and evaluated by two masked observers.

RESULTS

Prior to cutting, CCTs did not differ between OCT and USP measurements, with a high correlation between the two modalities (r²  = 0.8; p < 0.0001). Both systems succeeded in UT lamella preparation (CCT 40-130 μm) in 88% of cases. The OUP heads cut significantly deeper than the according SLc counterparts (p = 0.001), while the variance did not differ. The mean PL thickness increased significantly in the following incubation period (p = 0.01) with no difference between the keratome groups. Endothelial cell density (ECD) decreased significantly from before to 1 hr after preparation (-5.6%; p = 0.04), with no changes in the following 144-hr incubation period and no differences between the OUP and SLc group. Lamellar surface roughness (LSR) did not differ between both systems.

CONCLUSIONS

The SLc and the OUP system are both suited for the preparation of UT-DSAEK lamellae. Neither system differed significantly in variability, LSR or ECL, which did not increase during a 6-day incubation period.

Trends in Indications and Techniques of Corneal Transplantation in Iran from 2006 to 2013; an 8-year Review

Purpose:

To report changing trends in indications and techniques of corneal transplantation in Iran.

Methods:

We reviewed eye bank records of 47,129 patients who had undergone corneal transplantation between 2006 and 2013 at different eye centers throughout Iran.

Results:

The most common indication for corneal transplantation was keratoconus (KCN, n = 21,350 eyes, 45.3%), followed by bullous keratopathy (BK, n = 8,566 eyes, 18.2%), corneal opacity and scar (COS, n = 7,158 eyes, 15.2%), graft failure (n = 3,252 eyes, 6.9%), corneal dystrophies (n = 2,553 eyes, 5.4%), and infectious keratitis (n = 2,238 eyes, 4.7%). Over the study period, there was a significant increase in the frequency of BK (P = 0.001) and graft failure (P = 0.025), and a significant decrease in the relative frequency of COS (P = 0.012). The prevalence of KCN (P = 0.172), infectious keratitis (P = 0.107), and corneal dystrophies (P = 0.836) remained unchanged. The most common technique of corneal transplantation was penetrating keratoplasty (PKP, n = 33,476 eyes, 71.0%), followed by deep anterior lamellar keratoplasty (DALK, n = 8,363 eyes, 17.7%), Descemet's stripping automated endothelial keratoplasty (DSAEK, n = 3,516 eyes, 7.5%), tectonic (n = 1752, 3.7%), and keratolimbal allograft (KLAL, n = 19 eyes, 0.1%). Regarding the shift in surgical techniques, a significant increase was observed in DSAEK (P < 0.001), whereas PKP was significantly decreased (P = 0.005) over the 8-year period. No significant change was seen in the rates of DALK (P = 0.354), tectonic graft (P > 0.999) and KLAL (P = 0.151).

Conclusion:

KCN was the most common indication and PKP was the most prevalent technique used for corneal transplantation. Significant changes in surgical techniques were observed over the past 8 years; DSAEK demonstrated an increasing trend while PKP showed a decrease.

Fellow Eye Comparison of Descemet Membrane Endothelial Keratoplasty and Penetrating Keratoplasty

PURPOSE

To compare the visual outcomes and postoperative complications in patients undergoing penetrating keratoplasty (PKP) in 1 eye followed by Descemet membrane endothelial keratoplasty (DMEK) in their fellow eye.

METHODS

A retrospective analysis of 11 patients, who underwent a PKP procedure first in 1 eye and then a DMEK surgery in their fellow eye, was performed. Intraoperative and postoperative complications were recorded. Visual and refractive outcomes were also evaluated, including higher-order aberrations (HOAs) and contrast thresholds. A subjective questionnaire was used to evaluate patient satisfaction.

RESULTS

Both uncorrected and best-corrected visual acuities were significantly better in the case of DMEK when compared with that in the case of PKP (0.82 vs. 0.37 logMAR, P = 0.005; 0.61 vs. 0.21 logMAR, P = 0.011, respectively). Postkeratoplasty astigmatism, mean spherical equivalent, and HOAs were also significantly lower in eyes after undergoing DMEK than after undergoing PKP (3.90 vs. 0.89 diopters, P = 0.005; -3.90 vs. -0.68 diopters, P = 0.005; 6.81 vs. 1.71 µm, P = 0.043, respectively). Visual outcome and patient satisfaction were significantly better in those who underwent DMEK (2.91 vs. 4.45, P = 0.011; 3.27 vs. 5.64, P = 0.016, respectively). The estimated time for recovery and rehabilitation was significantly shorter after DMEK (64.0 vs. 9.3 days, P = 0.012). Contrast threshold was better after the DMEK. Ten of 11 patients preferred DMEK procedure.

CONCLUSIONS

The Patients preferred DMEK to PKP. The reasons for better patient satisfaction after DMEK included better uncorrected visual acuity, better best-corrected visual acuity, avoidance of surgery-induced astigmatism, and lower HOA.

Prevention and treatment of corneal graft rejection: current practice patterns of the Cornea Society (2011)

PURPOSE

To analyze current practice patterns in the prevention and treatment of corneal graft rejection for both penetrating keratoplasty (PK) and endothelial keratoplasty (EK) and to compare these patterns with previously reported practices.

METHODS

In 2011, an electronic survey was sent to 670 members of the Cornea Society worldwide addressing the routine postoperative management of corneal transplants at different time points, treatment of various manifestations of corneal graft rejection, and preferred surgical techniques.

RESULTS

A total of 204 of 670 surveys (30%) were returned and evaluated. All respondents used topical corticosteroids for routine postoperative management and treatment of endothelial graft rejection. Prednisolone was the topical steroid of choice in all clinical scenarios, similar to previous surveys from 1989 to 2004. Use of subconjunctival and systemic steroids increased for many scenarios of probable and definite graft rejection. Routine use of prednisolone decreased by approximately 10% from previous surveys, whereas difluprednate was used in 13% of high-risk eyes during the first 6 months. Dexamethasone, fluorometholone, and loteprednol use remained stable. Adjunctive topical cyclosporine use increased significantly for PK and EK. EK was the preferred technique for endothelial dysfunction, whereas PK and deep anterior lamellar keratoplasty were both used for keratoconus and anterior scars. Most respondents (75%) felt that graft rejection occurs more frequently after PK than after EK.

CONCLUSIONS

Prednisolone remains the treatment of choice for management and treatment of graft rejection; however, since the introduction of difluprednate, its use has declined slightly since the introduction of difluprednate. Despite perceived differences in rejection rates, there were no differences in prophylactic steroid treatment for PK and EK.

Comparison of Gebauer SLc and Moria CBm Carriazo-Barraquer ALK Microkeratomes for Descemet's Stripping Automated Endothelial Keratoplasty Preparation

PURPOSE

We compared the hand-guided Moria Carriazo-Barraquer (CBm) microkeratome with the fully automatic SLc microkeratome for Descemet's stripping automated endothelial keratoplasty (DSAEK)-lamella preparation and storage, vis-à-vis accuracy, endothelial cell loss (ECL), and lamellar surface roughness (LSR).

METHODS

A total of 18 human corneas were dissected with both the 300 μm CBm multi-use (n = 9) and the 300 µm SLc (n = 9) single-use heads, after which they were incubated for 6 d in a 5% dextran medium. Before preparation (0 h) and 1, 24, and 144 h after dissection, ECL and corneal thickness (CT) were measured by ultrasound pachymetry (USP) and optical coherence tomography (OCT). LSR was assessed by scanning electron microscopy (SEM) and evaluated by three masked observers.

RESULTS

Prior to cutting, CTs did not differ significantly between OCT or USP measurements, with a high correlation between the two modalities (r(2)= 0.94, p < 0.0001). One hour after preparation the anterior lamella showed a significantly higher dissection depth with the CBm (429.4 ± 21.8 µm) than the SLc (311.7 ± 54.8 µm, p = 0.0006), with the variance of the SLc system showing a trend towards higher values (p = 0.07). Anterior and posterior lamellae swelled significantly in the subsequent culture period. Both groups showed a significant ECL 1 h after preparation (p < 0.0001) with no significant difference between the systems (1 h: p = 0.44; CBm: - 9.4%, SLc: -11.7%), which stabilized over 144 h (144 h CBm: -13.9%, 144 h SLc: -10.3%). LSR did not differ significantly between both systems (p = 0.60).

CONCLUSIONS

The SLc system agrees more with the designated cutting depth than the CBm. The dissection produced a comparable LSR and a ∼10% ECL independently of the system. Further incubation of the prepared lamellae led to a swelling, but no further ECL.

Superior versus temporal approach in descemet membrane endothelial keratoplasty

PURPOSE

To compare superior vs temporal approach in patients who underwent Descemet membrane endothelial keratoplasty (DMEK).

DESIGN

Monocentric, prospective nonmasked study.

METHODS

A prospective analysis of 53 DMEKs between January and September 2013 was performed at the Charité-Universitätsmedizin Berlin. Only DMEK cases with an incision size of 2.3 mm and with at least 1 month of follow-up were included. The surgically induced astigmatism (SIA), changes in corneal aberrations and in spherical equivalent, visual acuity, endothelial cell density, and complications were evaluated.

RESULTS

Visual acuity improved significantly (0.70 ± 0.39 logMAR vs 0.32 ± 0.31 logMAR after 1 month (n = 48), 0.19 ± 0.15 logMAR after 3 months (n = 46), and 0.16 ± 0.17 logMAR after 6 months (n = 47) (P < .001)) regardless of the approach. SIA was significantly lower after temporal than after superior approach (1.42 ± 0.91 diopters [D] [n = 13] vs 0.81 ± 0.68 D [n = 13], P = .038). Change in total root mean square of all aberrations (RMS) (P = .046) at 6 mm pupil diameter, and change in total RMS (P = .019), third-order aberrations (P = .007), and fourth-order aberrations (P = .041) at 4 mm pupil diameter, demonstrated significantly lower results after temporal compared to superior approach. A higher rate of eyes after temporal approach underwent at least 1 rebubbling (39.1% vs 26.7%, P = .252). The endothelial cell density (P = .053) and the change in spherical equivalent (P = .145) did not differ significantly.

CONCLUSIONS

The temporal approach induces significantly less SIA and corneal aberration. There are no significant differences between superior and temporal approach according to the change in spherical equivalent, visual acuity, and endothelial cell density. The need for rebubbling is higher using the temporal approach.

Modified tectonic keratoplasty with minimal corneal graft for corneal perforation in severe Stevens--Johnson syndrome: a case series study

Background

Corneal perforation in severe Stevens-Johnson syndrome (SJS) presenting great therapeutic difficulties, the imperative corneal transplantation always result in graft failure and repeated recurrence of perforation. The aim of this study was to evaluate the effectiveness of a modified small tectonic keratoplasty (MSTK) with minimal corneal graft in the management of refractory corneal perforation in severe SJS.

Methods

Refractory corneal perforations in ten patients (10 eyes) with severe SJS were mended with a minimal corneal patch graft, under the guidance of anterior chamber optical coherence tomography, combined with conjunctival flap covering. The outcome measures included healing of the corneal perforation, survival of the corneal graft and conjunctival flap, relevant complications, and improvement in visual acuity.

Results

Corneal perforation healed, and global integrity was achieved in all eyes. No immune rejection or graft melting was detected. Retraction of conjunctival flap occurred in one eye, which was treated with additional procedure. Visual acuity improved in six eyes (60%), unchanged in three eyes (30%) and declined in one eye (10%).

Conclusions

The MSTK combined with conjunctival flap covering seems to be effective for refractory corneal perforation in severe SJS.

Corneal collagen cross-linking in keratoconus: a systematic review and meta-analysis

The aim of this study was to determine the effectiveness of corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus (KC). Some of the published literature, including a few small, randomized controlled trials (RCTs), demonstrated good results after CXL, but large RCTs with long-term follow-up to establish a cause-effect relationship are lacking. Using PubMed, EMBASE, and the Cochrane Library database, we searched for relevant studies published between October 2007 and March 2014. A comprehensive literature search was performed using the Cochrane Collaboration methodology to identify the effectiveness of CXL for treating KC. The primary outcome parameters included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refraction, corneal topography, and corneal thickness at baseline and at 1, 3, 6, 12, and 18 months after CXL. A total of 1171 participants (1557 eyes) were enrolled in this meta-analysis. CXL may be effective in halting the progress of KC for at least 12 months under certain conditions. However, further research from randomized trials is needed to confirm our findings.

Clinical outcome of repeat penetrating keratoplasty

PURPOSE

To compare the clinical outcome of regrafts with first grafts.

METHODS

Two-year outcome data were obtained from the Swedish Cornea Transplant Register for patients undergoing penetrating keratoplasty between 2001 and 2008. Only data from the 3 centers with follow-up return rates >75% were included. The survival and visual outcome of regrafts with the original diagnoses of keratoconus, Fuchs endothelial dystrophy (FED), or bullous keratopathy (BK) were compared with first grafts for the same diagnoses by univariate and logistic regression methods.

RESULTS

For keratoconus, the failure rate increased 3-fold in regrafts compared with first grafts (ie, 17% vs. 6%; P = 0.002) and doubled in FED regrafts (33% vs. 15%; P = 0.001). In BK, the failure rate was already high in first grafts, and the increase in failure of regrafts was minimal (P = 0.9). Visual acuity was also worse in regrafts compared with first grafts, mainly in the keratoconus and FED patients. In the keratoconus group, visual acuity with preferred correction was ≥0.5 in 69% of first grafts compared with only 55% in regrafts (P = 001). In FED, 52% of first grafts but only 19% of regrafts achieved visual acuity ≥ 0.5 (P = 0.001). The visual outcome of regrafts in BK was poor but little different from first grafts where fewer than 20% achieved visual acuity ≥ 0.5.

CONCLUSIONS

This analysis confirmed the poorer survival of regrafts where the original indication was keratoconus or FED. In addition, visual outcome was also worse than in the first grafts. However, the outcomes of regrafts in BK were similar to first grafts.

Indications of penetrating keratoplasty in southern India

AIM

To study the indications of penetrating keratoplasty in Southern India.

SETTINGS AND DESIGN

Retrospective study.

MATERIAL AND METHODS

Retrospective evaluation of eye bank records from December, 2002 to December, 2012 with respect to indications for penetrating keratoplasty.

RESULTS

During the period considered for study, 102 penetrating keratoplasties were performed. The leading indications for penetrating keratoplasty were corneal scarring (60.7%), followed by regrafting (12.7%), spheroidal degeneration (9.8%), aphakic bullous keratopathy (5.88%), pseudophakic bullous keratopathy (2.94%), acute infectious keratitis (2.94%), corneal dystrophy and keratoconus (4.9%). Healed infectious keratitis (72.88%) was the most common subcategory among the eyes with corneal scarring followed by traumatic corneal scars (16.12%).

CONCLUSION

Corneal scarring from healed infectious keratitis are the most common indication for keratoplasty in Southern India.

Comparison of treatments for bullous keratopathy in rabbits

The aim of the present study was to compare deep lamellar endothelial keratoplasty (DLEK) and penetrating keratoplasty (PK) treatments for bullous keratopathy (BK). In total, 36 healthy New Zealand white rabbits were randomly divided into 3 groups termed the experimental, DLEK and PK groups. The experimental control group received no treatment. The DLEK and PK groups were observed for corneal astigmatism at 1, 2, or 3 months post-surgery using a corneal topography instrument and a slit lamp microscope. The incidence of immune rejection after 3 months of recovery was determined using hematoxylin and eosin (H&E) staining. The corneal specimens from the surgery groups were compared with those from the control group. In the 12 rabbit eyes that underwent the DLEK surgery, the central cornea became clear after 1 week. After 3 months, these corneas were almost transparent and no eye infections or other complications were observed in 10 of the eyes, while surgical perforations in 2 eyes led to surgical lamellar failure. In the PK surgery group, in which 12 rabbit eyes were also treated, nine were almost transparent after 3 months of recovery, while three eyes were immunologically rejected due to the corneal grafts. The occur-rences of corneal astigmatism that were observed following DLEK and PK treatment were significantly different after 1, 2 and 3 months of recovery (P<0.05). Normal corneal staining was observed in the DLEK and PK rabbits subjected to H&E staining after 3 months of recovery. A BK animal model was established by curetting the Descemet’s membrane (DM film). In comparison with PK, DLEK is a superior surgical treatment for BK.

Changing indications and surgical techniques for corneal transplantation between 2004 and 2009 at a tertiary referral center

Purpose:

The aim of this study is to report the indications, techniques, and clinical outcomes of corneal transplantation and investigate any changing trends in surgical techniques over a 6 year period.

Materials and Methods:

Records of patients who had undergone any kind of corneal transplantation at Labbafinejad Medical Center, Tehran, Iran, from January 2004 to December 2009 were reviewed to determine the indications and types of corneal transplantation. Postoperative best-corrected visual acuity, refractive error, graft clarity, and complications were reported.

Results:

During this period, 1859 eyes of 1624 patients with a mean age of 41.3 ± 21.3 years underwent corneal transplantation. The most common indication was keratoconus (38.4%) followed by aphakic/pseudophakic bullous keratopathy (11.7%), previous failed grafts (10.6%), infectious corneal ulcers (10.1%), non-herpetic corneal scars (7.6%), trachoma keratopathy (4.7%), stromal corneal dystrophies (4.6%), post-herpetic corneal scar (3.7%), Fuchs’ endothelial dystrophy (0.8%), and congenital hereditary endothelial dystrophy (0.4%). Techniques of corneal transplantation included penetrating keratoplasty (PKP; 70.9%), deep anterior lamellar keratoplasty (DALK; 20.1%), conventional lamellar keratoplasty (LKP; 4.4%), and Descemet's stripping automated endothelial keratoplasty (DSAEK; 2.3%). Over the study period, there was a significant increase in the relative frequency of infectious corneal ulcers, failed grafts, and trachoma keratopathy. Additionally, a significant reduction was observed in PKP and LKP procedures, and volume of DALK and DSAEK increased significantly. At final follow-up, 69.0% of grafts were clear in the PKP group. This figure was 82.6%, 82.7%, and 97.6% in the DALK, LKP, and DSAEK groups, respectively.

Conclusion:

Keratoconus was the most common indication and PKP was the most prevalent technique used for corneal transplantation. However, significant changes in the indications and surgical techniques were observed from 2004 to 2009.