Corneal transplantation activity in Catalonia, Spain, from 2011 to 2018: Evolution of indications and surgical techniques

Study of a single eye bank. Characteristics and progression of corneal transplantation from 2016 through 2022 in Galicia (Spain)

OBJECTIVE

To describe the characteristics of donated and transplanted corneas, trends in surgical techniques, and indications for corneal transplantation, and the impact of COVID-19 on a Spanish tissue bank from 2016 through 2022.

METHODS

We conducted a retrospective analysis of corneal donation records from Complejo Hospitalario Universitario de A Coruña Cryobiology Unit and Tissue Bank from January 1st, 2016 through June 30th, 2022.

RESULTS

Corneal donations and transplants remained stable over 6.5 years, except for declines in 2020-2021. A total of 44.3% of all donated corneas were not transplanted, mainly due to tissue viability issues (41.4%). Donors averaged 60.2 ± 13 years, with a mean corneal endothelial cell count of 2701.3 ± 324.6 cells/mm² and a mean corneal clear zone diameter of 7.7 ± 0.7 mm. The preferred preservation method for keratoplasty was hypothermia (85,9%). Indications included endothelial dysfunction (53.8%), repeated keratoplasty (18.8%), corneal ectasia (15.4%), stromal opacity (7.6%), and tectonic causes (4.9%). Penetrating keratoplasty (PK) was more common (56.3%) than lamellar techniques (43.7%), but endothelial keratoplasty (EK) increased by 27.8% since 2019. EK, predominantly Descemet Membrane Endothelial Keratoplasty (DMEK, 94.1%), was used in 96.7% of endothelial dysfunction cases, although 28.6% were treated with PK. Deep anterior lamellar keratoplasty was primarily used for corneal ectasia (46.8%).

CONCLUSIONS

The Galicia Tissue Bank exceeds the European Eye Bank Association quality standards. Penetrating techniques remain predominant, but the trend is towards favor lamellar procedures, particularly DMEK. Endothelial dysfunction is the leading and growing indication for corneal transplantation.

Clinico-demographic profile and visual outcomes of pseudophakic bullous keratopathy in a multi-tier eyecare network in India

PURPOSE

The purpose of this study is to present the clinico-demographic characteristics of pseudophakic bullous keratopathy (PBK), its visual outcomes, factors associated with the choice of treatment, and poor visual outcomes of PBK.

METHODS

In this hospital-based retrospective study, electronic medical records data of new patients who presented to a multi-tier ophthalmology hospital network in India (November 2010-June 2022) were extracted. Patients with at least 4 weeks of follow-up were analyzed for visual outcome data. Bivariate analysis and multivariate logistic regression were used to determine the factors associated with the treatment choice and poor visual outcomes.

RESULTS

Of the 3,323,247 electronic records (with an average follow-up of 293 days) examined, 10,522 eyes of 10,158 patients (0.3%) had PBK. The majority were managed non-surgically ( n = 7372; 70.1%), with increased odds of poor visual outcome by 3.46 times (AdjOR: 3.04-3.92, P < 0.001). Those belonging to the non-paying category had higher odds of poor visual outcome (AdjOR: 1.48, 95%CI: 1.29-1.69; P < 0.001). Surgical management improved vision by 0.72 logMAR (95%CI: 0.60-0.73; P < 0.001). A total of 41.2% ( n = 113/274) of cases that underwent Descemet's membrane endothelial keratoplasty and 18.4% ( n = 285/1551) of Descemet's stripping endothelial keratoplasty attained last follow-up visual acuity (LVA) of 6/18 or better.

CONCLUSION

About three in every thousand patients had PBK. Surgical interventions improved visual acuity significantly. About four in ten patients who underwent DMEK attained a vision of 6/18 or better at the last follow-up visit. Markers of lower socioeconomic strata were independently associated with poor visual outcomes.

Delphi-Based Global Consensus on Adopting Endothelial Keratoplasty: An Endothelial Keratoplasty Learners Group Initiative

PURPOSE

To identify areas of consensus among experts on the performance of endothelial keratoplasty by using a modified Delphi approach, to help create a framework for novice surgeons to adopt these procedures.

METHODS

Thirty-one international experts in endothelial keratoplasty participated. Two rounds of electronic survey were followed by a hybrid, virtual meeting. Consensus was set at 75%, and results with agreement between 70% and 75% were deemed as achieving near consensus.

RESULTS

A consensus was reached for 98 statements covering the preoperative, intraoperative, and postoperative aspects of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping endothelial keratoplasty/Descemet stripping automated endothelial keratoplasty. Four statements achieved near consensus, and consensus could not be achieved for 11 statements. For DMEK, the panel supported a peel technique to prepare tissue for endothelium out DMEK, implanted via an injector and supported by a near full air/gas fill as a baseline procedure onto which more advanced techniques can be built. DMEK tissue should be marked to ensure correct orientation. An inferior peripheral iridotomy should be used to prevent pupil block when a near full air/gas fill in used in endothelial keratoplasty (EK). Descemet stripping automated endothelial keratoplasty was considered preferable to Descemet stripping endothelial keratoplasty where access to microkeratome preparation was available.

CONCLUSIONS

The Delphi process allowed areas of consensus on the performance of EK to be established by a group of international experts. The statements generated are a helpful framework for novice surgeons learning EK. Further research is needed to help determine what specific tomographic features indicate EK, when guttae are considered visually significant and how to approach combined aphakia and endothelial dysfunction.

Changing indications for and trends of keratoplasty in a tertiary comprehensive hospital in northern part of China from 2002 to 2021: a 20-year review

OBJECTIVE

To investigate indications and surgical procedures of keratoplasty in a tertiary comprehensive hospital in northern part of China over a 20-year period.

METHODS

All patients undergoing keratoplasty between January 1, 2002 to December 31, 2021 in a tertiary comprehensive hospital in northern part of China were retrospectively reviewed. The annual proportion of keratoplasty indications and surgical procedures was recorded and analyzed.

RESULTS

A total of 8266 keratoplasty procedures were included. Leading indications were keratoleukoma (n = 2108, 25.50%), followed by regraft (n = 1453 ,17.58%), corneal endothelial dysfunction (n = 1085, 13.13%), and keratoconus (n = 922,11.15%). A decreasing trend was observed for keratoleukoma (P < 0.01) and an increasing trend for corneal endothelial dysfunction (P < 0.01), regraft (P = 0.012), corneal limbal dermoids (P < 0.01) and congenital corneal opacity (P < 0.01). From 2002 to 2021, the proportion of penetrating keratoplasty (PK) had decreased from 73.95% (2002 to 2006) to 53.49% (2017 to 2021). On contrary, anterior lamellar keratoplasty (ALK) (459-705, 26.05-31.96%, P = 0.034) and endothelial keratoplasty (EK) (0-321, 0.00-14.55%, P < 0.01) became more prevalent from 2002 to 2021. For cases with corneal endothelial dysfunction, EK became the preferred technique (74.72%) in the recent 5 years.

CONCLUSION

Over the past 20 years, keratoleukoma and regraft have been the leading indications for keratoplasty. A noticeable shift in surgical preference from PK to DSAEK and ALK is evident, with key indications for keratoplasty including keratoleukoma, regraft, limbal dermoids, endothelial dysfunction, and keratoconus, respectively.

Andalusian Public Eye-Banks: a decade of continuous improvement

OBJECTIVES

To show donation data, number of keratoplasties and the changes in transplant indications and techniques that occurred in Andalusia in the period from 2013 to 2022.

MATERIALS AND METHODS

The present work is a retrospective and descriptive study that included all keratoplasties performed between January 2013 and December 2022 in Andalusia, as well as the evolution of the cornea donation and transplant activity of the public and private hospitals pertaining to the waiting list management system of the Public Health System of Andalusia. Transplants performed in private centers with corneas from outside Andalusia were excluded.

RESULTS

Cornea donation activity in Andalusia in the decade 2013-2022 has experienced a growth of more than 126%, while overall transplant activity has increased by 157% in public hospitals. Penetrating keratoplasty has decreased from 83% in 2013 to 43% in 2022, while lamellar techniques have increased from 17% to 57% in this same period. Since 2018, more lamellar transplants are performed than penetrating transplants. Regarding indications, endothelial conditions already represent the first cause of transplantation. In 2022 alone, the public Andalusian Eye Banks evaluated 1,054 corneas and prepared 281 endothelial grafts.

CONCLUSION

In the decade from 2013 to 2022 in Andalusia there has been an increase in donation activity and the number of keratoplasties. The public Eye Banks implementation in this period has played a key role in the widespread adoption of lamellar keratoplasty techniques and has enabled the transition to perform a greater number of lamellar keratoplasties compared to penetrating keratoplasty.

Clinical outcome analysis of two approaches to trypan blue dyeing for DMEK

To evaluate the clinical implications of the different trypan blue dyeing techniques used during liquid bubble (LBT) and manual peel (MPT) DMEK lenticule preparation techniques. This study retrospectively compared the degree to which endothelial cells are preserved using selective Descemet Membrane (DM) staining (LBT) versus bath-staining (MPT) when performed by a single surgeon, sourced from a single eye bank. Endothelial cell density measured after the 3-month follow-up was 1805 and 1916 cells/mm2 respectively, differing significantly (p = 0.012). A double-scroll graft formation was found and maintained until implantation in 94% of preparations with bath staining and 50% of preparations using selective DM staining. Preoperative visual acuity was comparable between preparation techniques at 0.4 logMAR as well as postoperatively, at an average of 0.1 logMAR. Reducing chemical stress on the endothelium by avoiding any contact with trypan blue allows for a significantly higher degree of cell preservation. However, achieving the often-desired double-scroll graft formation was possible less frequently. It remains unclear which factors define the differences graft scrolling behavior observed between LBT and MPT.

Current concepts in the management of cataract with keratoconus

This review analyzed all pertinent articles on keratoconus (KCN) and cataract surgery. It covers preoperative planning, intraoperative considerations, and postoperative management, with the aim of providing a simplified overview of treating such patients. Preoperatively, the use of corneal cross-linking, intrastromal corneal ring segments, and topo-guided corneal treatments can help stabilize the cornea and improve the accuracy of biometric measurements. It is important to consider the advantages and disadvantages of traditional techniques such as penetrating keratoplasty and deep anterior lamellar keratoplasty, as well as newer stromal augmentation techniques, to choose the most appropriate surgical approach. Obtaining reliable measurements can be difficult, especially in the advanced stages of the disease. The choice between toric and monofocal intraocular lenses (IOLs) should be carefully evaluated. Monofocal IOLs are a better choice in patients with advanced disease, and toric lenses can be used in mild and stable KCN. Intraoperatively, the use of a rigid gas permeable (RGP) lens can overcome the challenge of image distortion and loss of visual perspective. Postoperatively, patients may need updated RGP or scleral lenses to correct the corneal irregular astigmatism. A thorough preoperative planning is crucial for good surgical outcomes, and patients need to be informed regarding potential postoperative surprises. In conclusion, managing cataracts in KCN patients presents a range of challenges, and a comprehensive approach is essential to achieve favorable surgical outcomes.

Evaluation of biophysical alterations in the epithelial and endothelial layer of patients with Bullous Keratopathy

The cornea is a fundamental ocular tissue for the sense of sight. Thanks to it, the refraction of two-thirds of light manages to participate in the visual process and protect against mechanical damage. Because it is transparent, avascular, and innervated, the cornea comprises five main layers: Epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. Each layer plays a key role in the functionality and maintenance of ocular tissue, providing unique ultrastructural and biomechanical properties. Bullous Keratopathy (BK) is an endothelial dysfunction that leads to corneal edema, loss of visual acuity, epithelial blisters, and severe pain, among other symptoms. The corneal layers are subject to changes in their biophysical properties promoted by Keratopathy. In this context, the Atomic Force Microscopy (AFM) technique in air was used to investigate the anterior epithelial surface and the posterior endothelial surface, healthy and with BK, using a triangular silicone tip with a nominal spring constant of 0.4 N/m. Six human corneas (n = 6) samples were used for each analyzed group. Roughness data, calculated by third-order polynomial adjustment, adhesion, and Young's modulus, were obtained to serve as a comparison and identification of morphological and biomechanical changes possibly associated with the pathology, such as craters and in the epithelial layer and exposure of a fibrotic layer due to loss of the endothelial cell wall. Endothelial cell membrane area and volume data were calculated, obtaining a relevant comparison between the control and patient. Such results may provide new data on the physical properties of the ocular tissue to understand the physiology of the cornea when it has pathology.

Collagen cross-linking beyond corneal ectasia: A comprehensive review

The history of corneal cross-linking (CXL) dates back to 2003 when some German scientists investigated possible treatments to harden the corneal structure to increase its resistance in ectatic corneal diseases. Nowadays, CXL is considered the most effective therapy in ectatic corneal diseases due to its proven efficacy in hardening the cornea, thus halting the development of the disease. Since 2003, CXL applications have dramatically expanded and have been implemented in several other areas such as infectious keratitis, corneal edema, and before performing keratoplasty for various purposes. Moreover, several irradiation patterns are being studied to correct refractive errors, taking into account the corneal refractive changes that occur after the procedure. Currently, scleral cross-linking is also being investigated as a potential therapy in cases of progressive myopia and glaucoma. In this article, we provide a comprehensive overview of the available applications of cross-linking in nonectatic ocular conditions and highlight the possible future indications of this procedure.

Descemet membrane endothelial keratoplasty combined with presbyopia-correcting and toric intraocular lenses - a narrative review

Fuchs endothelial corneal dystrophy (FECD) is the leading indication for EK and may coexist with cataract and presbyopia. Notably, the outcomes of phacoemulsification in FECD patients are not as favorable as those in eyes without this condition. Historically, only monofocal intraocular lenses (IOLs) were recommended for these patients. However, recent reports have described the implantation of Premium-IOLs (such as Multifocal IOLs, Enhanced Depth of Focus IOLs, and Toric IOLs) in FECD eyes undergoing cataract surgery and Descemet membrane endothelial keratoplasty (DMEK). While the results are encouraging, they are not as optimal as those from unoperated eyes, especially when comparing simultaneous procedures to sequential ones. It's advised to perform the DMEK first to improve the accuracy of IOL calculations. Still, even successfully operated eyes may experience secondary graft failure or graft rejection after DMEK. The success rate of a secondary DMEK is typically lower than that of the initial procedure. Furthermore, if the postoperative thickness after DMEK is less than anticipated, laser enhancements might not be an option. There's a pressing need for more controlled and randomized clinical trials to ascertain the safety and effectiveness of Premium-IOLs for FECD eyes. This narrative review aims to collate evidence on the use of Premium IOL technologies in eyes receiving EK and to underscore key points for surgeons performing EK combined with cataract surgery.

An Overview of Corneal Transplantation in the Past Decade

The cornea is a transparent avascular structure located in the front of the eye that refracts light entering the eyes and also serves as a barrier between the outside world and the internal contents of the eye. Like every other body part, the cornea may suffer insult from trauma, infection, and inflammation. In the case of trauma, a prior infection that left a scar, or conditions such as keratoconus that warrant the removal of all or part of the cornea (keratoplasty), it is important to use healthy donor corneal tissues and cells that can replace the damaged cornea. The types of cornea transplant techniques employed currently include: penetrating keratoplasty, endothelial keratoplasty (EK), and artificial cornea transplant. Postoperative failure acutely or after years can result after a cornea transplant and may require a repeat transplant. This minireview briefly examines the various types of corneal transplant methodologies, indications, contraindications, presurgical protocols, sources of cornea transplant material, wound healing after surgery complications, co-morbidities, and the effect of COVID-19 in corneal transplant surgery.

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.

Trends in Corneal Transplantation in a Tertiary Hospital in Brazil

PURPOSE

The purpose of this study was to analyze the evolving trends of surgical techniques and indications of corneal transplantation (CT) at a tertiary hospital in Brazil.

METHODS

The medical records of all patients who underwent CT at the Hospital Oftalmológico de Sorocaba (Sorocaba Eye Hospital) from the Banco de Olhos de Sorocaba (Sorocaba Eye Bank) group in Sorocaba, Brazil, from January 1, 2012, to December 31, 2019, were analyzed. Data regarding age, sex, transplant indication, and surgical technique were collected.

RESULTS

A total of 16,250 CTs were performed. There was a statistically significant decreasing trend of keratoconus-related CT ( P < 0.0001), with rates dropping from 41.7% among all CTs in 2012 to 25.5% in 2019. Penetrating keratoplasty, anterior lamellar keratoplasty, and endothelial keratoplasty (EK) accounted for 59.3%, 27.1%, and 7.8% of the CTs performed in 2012 and 33.3%, 16.4%, and 39.9% in 2019, respectively. A statistically significant decreasing trend was observed for penetrating keratoplasty ( P < 0.0001) and anterior lamellar keratoplasty ( P < 0.0001), whereas EK showed a statistically significant increasing trend during the period ( P < 0.0001). Among EKs, Descemet membrane EK increased statistically significantly from 12.8% in 2012 to 74.4% in 2019 ( P < 0.0001).

CONCLUSIONS

This study shows relevant evolving trends in indications and preferred CT techniques in a tertiary hospital in Brazil.

Keratoconus: An updated review

Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.