Need For Corneal Transplantation Research Articles

Demographic and Systemic Risk Factors for Persistent Corneal Edema Following Cataract Surgery in Patients With and Without Diabetes

PurposeTo identify risk factors associated with the development of corneal edema (CE) and the need for corneal transplantation following cataract surgery. DesignRetrospective cohort study. MethodsSetting: Nation-wide sample of Medicare beneficiaries from 2011-2015. Study PopulationMedicare beneficiaries aged over 65 years who received cataract surgery between 2011-2014 with at least 1 year of continuous follow-up. Data was retrieved from the Denominator and Physician Supplier Part B file from the Center for Medicare and Medicaid Services. Main Outcome(s) and Measure(s)The main outcome was the association between demographic characteristics (e.g. age, sex, race/ethnicity) and systemic factors including diabetes status, hypertension, and tobacco use on the incidence of CE and the subsequent need for corneal transplantation following cataract surgery. ResultsAmong 187,746 beneficiaries, 67,734 had diabetes and 120,012 did not. Beneficiaries with diabetes were more likely to develop CE compared to those without (Odds ratio [OR] 1.19, 95% Confidence Interval [CI] [1.02-1.40]). Compared to those aged 65-74, beneficiaries aged 75-84 and over 85 were more likely to develop CE (OR 1.29 [1.09-1.52]) and OR 1.96 [1.55-2.46], respectively). Asian (OR 2.42 [1.66-3.40]), Hispanic (OR 2.60 [1.73-3.74]), and North American Native (OR 3.59 [1.78-6.39]) race was associated with increased likelihood of developing CE. North American Native beneficiaries had higher risk of requiring corneal transplantation compared to White beneficiaries (OR 9.30 [2.26-25.31]). Female sex decreased likelihood of requiring corneal transplantation post-operatively (OR 0.56 [0.36-0.87]). Amongst those with diabetes, the presence of proliferative diabetic retinopathy increased the likelihood of developing CE (OR 1.94 [1.05-3.39]). ConclusionOlder age, diabetes, and non-White race elevate the risk of CE following cataract surgery, with race incurring the highest risk. Further research is needed to understand the factors underlying the significantly increased risk of CE in racial and ethnic minorities within the United States.

Utility of artificial intelligence in the diagnosis and management of keratoconus: a systematic review.

The application of artificial intelligence (AI) systems in ophthalmology is rapidly expanding. Early detection and management of keratoconus is important for preventing disease progression and the need for corneal transplant. We review studies regarding the utility of AI in the diagnosis and management of keratoconus and other corneal ectasias. We conducted a systematic search for relevant original, English-language research studies in the PubMed, Web of Science, Embase, and Cochrane databases from inception to October 31, 2023, using a combination of the following keywords: artificial intelligence, deep learning, machine learning, keratoconus, and corneal ectasia. Case reports, literature reviews, conference proceedings, and editorials were excluded. We extracted the following data from each eligible study: type of AI, input used for training, output, ground truth or reference, dataset size, availability of algorithm/model, availability of dataset, and major study findings. Ninety-three original research studies were included in this review, with the date of publication ranging from 1994 to 2023. The majority of studies were regarding the use of AI in detecting keratoconus or subclinical keratoconus (n=61). Among studies regarding keratoconus diagnosis, the most common inputs were corneal topography, Scheimpflug-based corneal tomography, and anterior segment-optical coherence tomography. This review also summarized 16 original research studies regarding AI-based assessment of severity and clinical features, 7 studies regarding the prediction of disease progression, and 6 studies regarding the characterization of treatment response. There were only three studies regarding the use of AI in identifying susceptibility genes involved in the etiology and pathogenesis of keratoconus. Algorithms trained on Scheimpflug-based tomography seem promising tools for the early diagnosis of keratoconus that can be particularly applied in low-resource communities. Future studies could investigate the application of AI models trained on multimodal patient information for staging keratoconus severity and tracking disease progression.

Diagnosing and monitoring the characteristics of Acanthamoeba keratitis using slit scanning and laser scanning invivo confocal microscopy.

Acanthamoeba keratitis (AK) is a serious and potentially blinding ocular infection caused by the free-living amoeba, Acanthamoeba. Invivo confocal microscopy (IVCM) is a non-invasive device which has been proven of great use to diagnose Acanthamoeba infections immediately. The aim of this review was to establish different patterns and signs of AK that appear on the IVCM both before and after treatment. A systematic review of the literature from 1974 until September 2021 was performed using Embase and PubMed, following The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Twenty different signs of AK were observed using IVCM. The included studies used vastly different criteria to diagnose infections, ranging from just 1 to 13 of the signs, demonstrating the current lack of a standardised diagnosis of this infection using the IVCM. The appearance of double wall cysts, trophozoites, signet rings, target signs and clusters were shown to be pathognomonic to AK infections. Bright spots located in the corneal epithelium were demonstrated as non-reliable predictors of AK. The presence of cysts in clusters and single file can predict the need for corneal transplantation. The morphological changes in cysts using the IVCM following treatment were described as breaking down to hollow forms and occasionally surrounded by black cavities. Using this information, a visual guideline for identifying AK signs in diagnosis and follow-up using IVCM was created. Increased awareness of the different signs and patterns of AK that appear on the IVCM is crucial in order to correctly identify an infection and increase the potential of this device. Our guidelines presented here can be used, but further studies are needed in order to determine the relationship and aetiology of these signs and cellular changes on the IVCM both before and after anti-amoeba treatment.

Late recurrence of corneal dystrophy treated with phototherapeutic keratectomy combined with epikeratophakia using double lenticules

Phototherapeutic keratectomy (PTK) combined with epikeratophakia (EP) using double lenticules through small-incision lenticule extraction (SMILE) after late recurrence was used in a patient with Reis-Bückler corneal dystrophy (RBCD) who underwent bilateral PTK 9.5 years previously. Opacity recurred at 4 years, with PTK + EP being performed using SMILE-derived lenticules, and at 5.5 years with an uncorrected visual acuity of 20/100 and disrupted counting fingers in the right and left eyes. PTK + EP in the right eye and PTK on the original lenticule in the left eye were performed. Manifest refraction was −4.25/−2.5 × 155 with a corrected distance visual acuity (CDVA) of 20/20 and −3.50/−0.75 × 140 with a CDVA of 20/20 in the right and left eyes, respectively, 2 months postoperatively. Lenticules remained transparent and well-attached to the corneal stroma, and the corneal epithelium reshaped successfully. The feasibility of repeated PTK + EP in patients with multiple RBCD recurrences was demonstrated, delaying the need for corneal transplantation.

Whole-Exome Sequencing of 24 Spanish Families: Candidate Genes for Non-Syndromic Pediatric Keratoconus.

Keratoconus is a corneal dystrophy that is one of the main causes of corneal transplantation and for which there is currently no effective treatment for all patients. The presentation of this disease in pediatric age is associated with rapid progression, a worse prognosis and, in 15-20% of cases, the need for corneal transplantation. It is a multifactorial disease with genetic variability, which makes its genetic study difficult. Discovering new therapeutic targets is necessary to improve the quality of life of patients. In this manuscript, we present the results of whole-exome sequencing (WES) of 24 pediatric families diagnosed at the University Hospital La Paz (HULP) in Madrid. The results show an oligogenic inheritance of the disease. Genes involved in the structure, function, cell adhesion, development and repair pathways of the cornea are proposed as candidate genes for the disease. Further studies are needed to confirm the involvement of the candidate genes described in this article in the development of pediatric keratoconus.

Short-term visual outcome with sclerocorneal contact lens on irregular cornea.

The purpose is to study the change in visual acuity obtained with sclerocorneal contact lens (SCL) in patients with irregular corneal astigmatism. A prospective pre-post observational study was designed to include consecutive consenting patients with irregular corneal astigmatism and best-corrected visual acuity worse than 6/12 and fitted with SCL. Visual acuity was assessed using Snellen charts before fitting SCL and 1 week after the fit and converted to the equivalent logMAR units for analysis. We included 51 eyes of 41 patients with a mean age of 26.31 ± 8.86 of which 32 (78%) were men. Keratoconus was the most common indication (n = 42 eyes, 82.35%), followed by corneal scar (n = 3, 4%), post keratoplasty (n = 2, 4%), high myopia (n = 2, 4%), pellucid marginal degeneration (n = 1, 2%), and aphakia (n = 1, 2%). The mean overall uncorrected visual acuity improved significantly (P < 0.001) with SCL from 1.18 ± 0.34 logMAR (6/120 Snellen's equivalent) to 0.27 ± 0.15 (6/9 Snellen's equivalent) at 1-week post-SCL fitting. The mean overall best spectacle-corrected visual acuity improved from 0.89 ± 0.45 logMAR (6/36 Snellen's equivalent) to 0.26 ± 0.15 (6/9 Snellen's equivalent) at 1-week post-SCL fitting. Sclerocorneal contact lens improves visual acuity significantly in patients with irregular corneal astigmatism and reduces the need for corneal transplantation.

Argument for Prompt Corneal Cross-Linking on Diagnosis of Keratoconus in a Pediatric Patient.

Strong evidence suggests that corneal crosslinking is a safe procedure capable of stopping or slowing down the progression of keratoconus, avoiding visual loss associated with progression, and delaying or preventing the need for corneal transplantation. The progressive and chronic nature of the disease makes the option for prompt crosslinking upon keratoconus diagnosis in a pediatric patient valid.

Mucopolysaccharidosis: A broad review.

Mucopolysaccharidosis (MPS) is a group of genetic disorders with seven types and 13 subgroups which are characterized by an inherent deficiency of the enzymes responsible for the degradation of glycosaminoglycans (GAGs). Defective breakdown of GAG products leads to their widespread accumulation within the lysosomes of various organs involving the eye, central nervous system, skeletal, ocular, nervous, respiratory, cardiac, and the gastrointestinal systems. Clinical spectrum varies from mild systemic and ocular abnormalities with a normal life span to severe phenotype, fatal in the first few months of life. Visual disability due to corneal clouding, retinopathy, and optic nerve involvement causes additional impairment of physical and cognitive functions. Treatment modalities such as bone marrow transplantation and enzyme replacement therapies help in increasing the life span as well as the quality of life of the affected patients. For patients with significant corneal clouding, keratoplasty is the answer. The decision to proceed with keratoplasty is governed by various factors such as the motivation of the patient and his family, other systemic affections and anesthesia concerns. A detailed preoperative counseling should be done regarding the expected visual outcomes in the presence of other ocular comorbidities and the postoperative complication such as graft re-opacification, rejection and glaucoma. Future treatment options such as targeted gene therapy and substrate reduction therapy hold promise to reverse corneal clouding, thereby obviating the need for corneal transplantation. These treatment therapies are still in the experimental stages and human trials are needed to validate their outcomes.

The impact of having a relative in a need for cornea: the Knowledge, Attitude, and Willingness for Corneal Donation (KAWCD) questionnaire.

Despite the advancement in the field of corneal transplantation, corneal donation is still the only source for cornea. In our study, we aimed to find predictors for a person's willingness toward cornea donation, and the impact of having a relative in a need for cornea transplantation on the willingness to donate cornea. The study included two cohorts to be compared, first degree relatives of patients waiting for corneal transplantation, and general ophthalmology patients who do not have relatives waiting for corneal donation. We designed questionnaire on Knowledge, Attitude, and Willingness for Cornea Donation (KAWCD), a tool specifically designed to measure the knowledge about corneal donation, and the attitude towards it. A total of 269 participants were included in this study, with a mean age of 49.59 (± 17.24) years. We included 182 (67.7%) participants who did not have a relative with or in need for corneal transplantation, and 87 (32.3%) participants who are first degree relatives to patients on the waiting list for corneal transplantation. Upon assessing factors predicting willingness for corneal donation, we found that attitude (p < 0.001; OR 1.126 (95% CI 1.08 to 1.17)) and age (p = 0.022; OR 0.973 (95% CI 0.95 to 0.99)) are the only predictors for willingness to donate. We found that the willingness to donate cornea is related to the attitude, rather than the knowledge about corneal donation. We believe awareness campaigns should focus on encouragement to donate corneas, rather than providing information about it.

The Main Aspects of Corneal Transplantation in Ukraine and in the World: Demand Analysis, Keratoplasty Types and Future Development

The article presents information about the history and current state of corneal transplantation in Ukraine. Currently, no more than 400 keratoplasties per year are performed in Ukraine. However, the need for corneal transplantation in our country is much higher. The authors show that it is extremely important to eliminate the deficit of the donor cornea for keratoplasty and increase the number of corneal transplantations in Ukraine. It is necessary to expand the number of bases for donor corneal removal and include keratoplasty in the list of medical services funded by the National Health Service of Ukraine.For the development of corneal transplantation in Ukraine using the tissues of the deceased donor, it is necessary to solve a number of important tasks: to create positive attitude in society to donation after death, starting from school (to develop conscious informed and free consent for donation), to ensure that the population is informed about the essence of the right to be a donor of their organs or tissues after death and the mechanisms for recording their consent (or disagreement); to create conditions for documenting the consent of individuals to the opportunity to be a donor of their organs or tissues after death; to introduce a state program for the development of corneal transplantation in Ukraine with its proper funding.

Visual rehabilitation using miniscleral lens in advanced keratoconus

Aim: The aim of this study is to visually rehabilitate patients with advanced keratoconus with miniscleral contact lens. Materials and Methods: Miniscleral lens were prescribed in 11 eyes of 8 patients with advanced keratoconus. Inclusion criteria Amsler Krumeich Grade 2 with poor spectacle corrected visual acuity (<0.5logMAR) for the duration of 1 year. Results:Mean age was 18.75 years. Males and females were 50% each. Mean of uncorrected, spectacle corrected, best-corrected visual acuity with contact lens was 1.28logMAR, 0.96logMAR, and 0.12logMAR, respectively. Visual improvement was minimal with spectacles (0.5 Snellen lines, 0.32logMAR), whereas miniscleral contact lens showed additional improvement of 4.5 Snellen lines (1.16logMAR), respectively. Conclusion: Visual rehabilitation with miniscleral contact lens in advanced keratoconus showed excellent improvement in visual acuity and reduced the need for corneal transplantation.

Lamellar Keratoplasty for Advanced Keratoconus.

Ectatic corneal diseases are a group of disorders resulting in progressive corneal steepening and thinning. Keratoconus, keratoglobus, pellucid marginal degeneration, post-keratorefractive ectasia, and corneal graft ectasia are the types of corneal ectasia. Early diagnosis with appropriate diagnostic tools can help prevent progression, eliminating the need for corneal transplantation. Lamellar or full thickness corneal transplantation are the treatment options for advanced diseases. Although the visual outcomes of penetrating keratoplasty are comparable to anterior lamellar keratoplasty (ALK) especially in keratoconus, ALK is the preferred treatment of choice considering benefits including reduced graft rejection, less long-term complications, and better graft survival. This article reviews the various surgical techniques in ALK with its clinical outcomes in advanced keratoconus.

Simultaneous Interpenetrating Polymer Network of Collagen and Hyaluronic Acid as an In Situ-Forming Corneal Defect Filler.

Timely treatment of corneal injuries injury can help to prevent corneal scarring, blindness, and the need for corneal transplantation. This work describes a novel hydrogel that can fill corneal defects and assist in corneal regeneration. This hydrogel is a simultaneous interpenetrating polymer network (IPN) composed of collagen cross-linked via strain-promoted azide-alkyne cycloaddition reaction and hyaluronic acid cross-linked via thiol-ene Michael click reaction. The formation of the IPN gel was confirmed via FTIR spectra, UV-vis spectra, and morphological changes. We compared the gelation time, mechanical properties, transmittance, and refractive index of the IPN gel to the collagen gel, hyaluronic acid gel, and semi-IPN gel. The IPN combined the advantages of collagen and hyaluronic acid gels and supported corneal epithelial cell growth on its surface. When applied to corneal stromal defects in vivo, the IPN avoided epithelial hyperplasia, decreased stromal myofibroblast formation, and increased tight junction formation in the regenerated epithelium.

Combined surface ablation+CXL for keratoconus

AbstractKeratoconus treatment should be aimed to improve the optical inefficiency of the irregular cornea and halt the disease progression that may lead to the need for corneal transplantation. Corneal collagen cross‐linking (CXL) using Riboflavin and ultraviolet A has been used to stabilize the cornea with progressive keratoconus or ectatic corneal disorders after corneal refractive procedures. Studies demonstrated that the simultaneous wavefront optimized (WG PRK) or topography guided (TG PRK) approach of photore‐fractive keratectomy (PRK) plus CXL offers improvements in uncorrected distance acuity (UDA), best distance acuity(BDA), and topographic irregularity, even if the surgical goal is not a refractive end point. Combining photorefractive keratectomy (PRK) with CXL or accelerated CXL offers keratoconus patients both stability and improvement in functional vision. However, different excimer laser platforms have different ablation patterns and different algorithms for topography‐guided ablation. Additionally, mechanical and laser debridement of the corneal epithelium (PRK versus transepithelial PRK) may result in different patterns of ablation and different clinical results. Though the conventional refractive components of sphere and cylinder may be simultaneously incorporated into the treatment profile, in the treatment of keratoconus, tissue sparing is the prime consideration, and therefore, PRK typically limits the maximum depth of tissue ablation to less than 50mm. Several CXL protocols result in more cross‐linking and a greater increase in Young's modulus, less corneal cross‐linking (a smaller increase in Young's modulus) may still have the same clinical effect (in terms of disease stabilization). In other words, the optimum CXL parameters to produce the clinically desired effect (in terms of stabilization or prophylaxis) are not known. A reduction in HOA after TG‐PRK in keratoconus eyes (with or without the addition of CXL) is not surprising and is a consistent finding in published studies. Diffuse corneal haze, which emerges in a few days after CXL in virtually all eyes, generally resolves over time. It is identified as a dust‐like change in the stroma. In addition, some patients suffer from scarring that persists and can decrease visual acuity. However, these two words— “haze” and “scar”—are sometimes used interchangeably in the literature.

Descemet Membrane Suturing for Large Descemet Membrane Detachment After Cataract Surgery

To study the outcomes of Descemet membrane (DM) suturing for moderate to severe Descemet membrane detachment (DMD) after cataract surgery. This is a retrospective case review of all patients who underwent DM suturing for moderate to severe DMD after cataract surgery in a tertiary training eye care hospital from January 2017 to December 2017. Demographic details, type of cataract, type of cataract surgery, intraoperative complications, severity of DMD, time to repair, and post-DM suturing visual and clinical outcomes were documented. Forty-nine patients were included during the study period with a mean age of 67.7 ± 9.7 years. In total, 79.5% had immature cataracts. Median precataract LogMAR visual acuity was 0.78 (IQR 0.69-1.13). In total, 61.2% underwent manual small-incision cataract surgery, 32.6% had phacoemulsification, 2% had extracapsular cataract extraction (ECCE), and 6% underwent small-incision cataract surgery with trabeculectomy. In total, 44.9% were operated on by trainees and 55.1% were operated on by consultants. In total, 22.4% had primary air descemetopexy during the cataract surgery and failed treatment. All patients had attached DM in the immediate postoperative period. None of them had secondary angle closure glaucoma. At the final follow-up, 42 (85.7%) had clear corneas and 7 (14.3%) had corneal decompensation needing endothelial keratoplasty. Of these 7 patients, 2 (28.5%) had Fuchs dystrophy and 3 (42.8%) had associated DM loss. The median LogMAR visual acuity at the final follow-up was 0.39 (IQR 0.3-0.78). DM suturing can reattach DM, especially in moderate to severe, recurrent DMD with fewer postoperative complications and thereby reduce the need for corneal transplantation.

Alginate encapsulated multipotent adult progenitor cells promote corneal stromal cell activation via release of soluble factors.

To reduce the increasing need for corneal transplantation, attempts are currently aiming to restore corneal clarity, one potent source of cells are multipotent adult progenitor cells (MAPC®). These cells release a powerful cocktail of paracrine factors that can guide wound healing and tissue regeneration. However, their role in corneal regeneration has been overlooked. Thus, we sought to explore the potential of combining the cytoprotective storage feature of alginate, with MAPC to generate a storable cell-laden gel for corneal wound healing. 72 hours following hypothermic storage, alginate encapsulation was shown to maintain MAPC viability at either 4 or 15°C. Encapsulated MAPC (2 x106 cells/mL) stored at 15°C presented the optimum temperature that allowed for cell recovery. These cells had the ability to reattach to tissue culture plastic whilst exhibiting normal phenotype and this was maintained in serum-free and xenobiotic-free medium. Furthermore, corneal stromal cells presented a significant decrease in scratch-wounds in the presence of alginate encapsulated MAPC compared to a no-cell control (p = 0.018). This study shows that immobilization of MAPC within an alginate hydrogel does not hinder their ability to affect a secondary cell population via soluble factors and that these effects are successfully retained following hypothermic storage.

Corneal collagen crosslinking in kids

Corneal collagen crosslinking (CXL), recently FDA-approved, appears to be safe and effective for adult and pediatric patients, potentially obviating the need for corneal transplantation. There is a need to find ways of reliably testing children in high risk groups. Furthermore, current protocols for performing CXL in children need to be elucidated.

134: THE EFFECTIVENESS OF CXL IN THE TREATMENT OF KERATOCONUS

Background and aims:Keratoconus is characterized by corneal ectasia and irregular astigmatism, which can lead to diminished vision and corneal scarring. Keratoconus is a condition that causes corneal ectasia and reduced...

Cross-linking for microbial keratitis.

Microbial keratitis is one of the leading causes of ocular morbidity. The standard treatment consists of antibiotics, which is intensive and is fraught with risks of antibiotic resistance. Corneal collagen cross-linking (CXL) has recently been advocated as an adjunctive therapy for management of microbial keratitis. The addition of CXL to ongoing antimicrobial treatment can have a potential effect on overall duration of the disease, need for corneal transplantation, final visual outcome, and long-term impact on drug resistance pattern. CXL has been used in cases with bacterial, fungal as well as amoebic keratitis. However, so far the reported results have been variable and the evidence is largely anecdotal. The debate over the safety and efficacy of this modality continues especially with regards to its utilization in early phases of the disease when the corneal involvement is limited to the anterior stroma. CXL appears to be a promising adjunctive treatment in selective cases of mild to moderate bacterial keratitis. Its efficacy in fungal and amoebic keratitis is questionable. Treatment protocols in microbial keratitis need to be individualized. Long-term, prospective, randomized trials are needed to determine its usefulness in microbial keratitis.

Nationwide reduction in the number of corneal transplantations for keratoconus following the implementation of cross-linking.

Keratoconus is characterized by corneal ectasia and irregular astigmatism, which can lead to diminished vision and corneal scarring. Approximately 10-20% of patients with keratoconus eventually require a corneal transplant. Corneal cross-linking (CXL) is a relatively new treatment that may help prevent the need for corneal transplantation. Here, we investigated whether the introduction of CXL has reduced the number of corneal transplants performed annually. Data regarding the transplantation procedures performed in patients under the age of 50years were extracted from the Dutch National Organ Transplant Registry. The number of corneal transplants performed prior to (i.e. in 2005 through 2007) and following the introduction of CXL (i.e. in 2012 through 2014) were compared. Furthermore, a trend analysis on annual keratoplasties over time was performed. Approximately 25% fewer corneal transplants were performed in the 3-year period following the introduction of CXL compared to the 3-year period prior to the introduction of CXL (201 versus 269 transplants, respectively; p=0.005). Age, gender and visual acuity were similar between the patient groups in the two time periods. Trend analysis also demonstrated a significant decrease in the amount of corneal transplants (p=0.001). Significantly fewer corneal transplants were performed for treating keratoconus following the nationwide introduction of CXL. This reduction suggests that corneal cross-linking can significantly reduce the need for corneal transplantation.