Background and Objective: Limbal stem cell deficiency (LSCD) describes the clinical condition when there is dysfunction of the corneal epithelial stem/progenitor cells and the inability to sustain the normal homeostasis of the corneal epithelium. The limbal stem cells are located in a specialized area of the eye called the palisades of Vogt (POV). There have been significant advances in the diagnosis and management of LSCD over the past decade and this review focuses on the pathophysiology of LSCD, its clinical manifestations, diagnosis, and causes.Methods: Papers regarding LSCD were searched using PubMed to identify the current state of diagnosis and causes of LSCD published through to June 2022.
Key Content and Findings: LSCD is clinically demonstrated by a whorl-epitheliopathy, loss of the POV, and conjunctivalization of the cornea. The diagnosis of this condition is based on clinical examination and aided by the use of impression cytology, in vivo confocal microscopy, and anterior segment optical coherence tomography (asOCT). There are many causes of LSCD, but those which are most common include chemical injuries, aniridia, contact lens wear, and Stevens-Johnson syndrome (SJS).Conclusions: While this condition is most commonly encountered by corneal specialists, it is important that other ophthalmologists recognize the possibility of LSCD as it may arise in other co-morbid eye conditions.
The prevalence of diabetic retinopathy (DR) continues to increase in pregnant females; these individuals are also at a higher risk of disease progression. The lack of evidence regarding the safety and efficacy of current treatment options in pregnancy makes disease management particularly challenging.All pregnant women with diabetes should have a prenatal DR screening, as well as receive counseling regarding the progression and management of DR during pregnancy. Optimal blood glucose and blood pressure control should be encouraged. For patients with proliferative diabetic retinopathy (PDR) in the absence of visually significant diabetic macular edema (DME), panretinal photocoagulation (PRP) remains a safe and effective treatment option. Visually significant DME can be treated with focal laser if areas of focal leakage are identified in the macula on fluorescein angiogram, intravitreal steroids or anti-vascular endothelial growth factor (VEGF) agents, The theoretical risk of anti-VEGF agents to the fetus should be considered and the patients should be extensively counselled regarding the risks and benefits of initiating anti-VEGF therapy before initiating treatment. When the decision is made to treat with anti-VEGF agents, Ranibizumab should be the agent of choice. In conclusion, ophthalmologists should make treatment decisions in pregnant patients with DR on a case-by-case basis taking into consideration disease severity, risk of permanent threat to vision, gestational age, and patient preferences.
Abstract: Four challenging and unusual retinal cases: (I) 11-year follow-up for retinal hemangioblastoma with von Hippel-Lindau (VHL) disease; (II) treatment for central serous chorioretinopathy (CSC)—observation, half does photodynamic therapy (PDT) or micropulse laser photocoagulation; (III) diagnosis and treatment for a child with optic nerve defect; (IV) the optional treatment for retinal detachment (RD) with iridolenticular choroidal coloboma, were presented and discussed by three international retinal specialists at a retinal clinical round in Fundus Diseases Center of Zhongshan Ophthalmic Center (ZOC). The discussion helps us a better understanding of the pathogenesis and managements of these four retinal diseases and their association with systemic conditions.
Abstract: The disease burden of diabetic retinopathy (DR) is tremendous around the world. While DR is correlated with hemoglobin A1c (HbA1c) and duration of diabetes, genetic differences likely account for variation in susceptibility to DR. DR is a polygenic disorder with demonstrated heritability. However, linkage and admixture analyses, candidate gene association studies, and genome-wide association studies (GWAS) have not identified many loci for DR that can be consistently replicated. Larger, collaborative, multi-ethnic GWAS are needed to identify common variants with small effects. Rigorous defining of controls groups as patients with a long duration of diabetes without DR, and case groups as patients with severe DR will also aid in finding genes associated with DR. Replication in independent cohorts will be key to establishing associated loci for DR. Investigations of mitochondrial DNA and epigenetics in DR are ongoing. Whole exome sequencing presents new opportunities to identify rare variants that might be implicated in DR development. Continued research in the genetic epidemiology of DR is needed, with the potential to elucidate pathogenesis and treatment of an important disease.
Abstract: The highly competitive offer of medical training programs and schools, globalization and constant mobility of physicians and medical students (MS), and the commitment to society to deliver competent physicians, demands the definition of performance standards. This would allow to make their performances comparable no matter where they studied or which textbook did they used as reference, to have evaluation mechanisms that guarantee mastery of the integral evaluation of the performance. Assessment has been the key in the teaching-learning process as this obtains a formative and summative element, at different moments, from the extent to which the students have acquired knowledge, skills and attitudes. The progress of the learner must be enhanced with effective feedback on their performance and self-direction of the results obtained in each of the mechanisms established. If, traditionally, this has been considered as the accreditation of compliance with a standard, the evaluation also functions in an integral way as a formative process that identifies advances and deficiencies in the training of residents that allows the definition of actions and strategies for improving the operation of the programs. Different assessment mechanisms are associated with the areas of competence domain, some of the most common tools are: theoretical exams, checklists and rubrics, portfolio, projects and challenges. However, the importance of defining standards which are perceived as fair and designed according to the learning objectives remains a priority to guarantee the credibility of the evaluation agencies and institutions. Some strategies to assure credibility include the involvement of expert and trained evaluators, allowing the process to be carried out with transparency and diligence, and the principles employed should be supported by educational research.
Abstract: There are many advantages to understanding the genetics of human disease. Genetic markers can be used to calculate the risk of developing a disease, and elucidation of genetic risk factors can pinpoint the molecular aetiology of disease, which can facilitate the development of targeted therapies. Diabetic retinopathy (DR) is a common complication of diabetes that has a significant impact on quality of life. It has a clear genetic component, but determination of the genetic risk factors has proven difficult. To date, genome-wide studies for DR have been conducted on relatively small patient cohorts compared to other complex eye diseases and replication of genetic findings has been limited. The disease is highly heterogeneous, confounding attempts to classify patients into appropriate groups for genetic analysis and making direct comparisons between studies challenging. Future studies to determine the genetic causes of DR will need to focus on larger sample sizes, detailed phenotyping and appropriate classification of patients. Global co-operation and meta-analyses combining data from multiple studies will be critical to the discovery of genetic risk loci for DR.
Abstract: Between 2011 and 2013, two large-scale cohort epidemiology studies were launched in Shanghai: the SCALE study, which aimed to provide ocular public health services to cover the entire youth population in Shanghai, and the SCES, which was based on sample surveys and aimed to provide information on the prevalence and incidence of visual impairment and different types of refractive errors. A total of 910,245 children and adolescents were finally enrolled in the SCALE study; three possible methods for monitoring refractive error without mydriasis were tested, and the agreement between the refractive outcomes of three commonly used autorefractors were examined to ensure the accuracy of the results of the SCALE study. A total of 8,627 children were enrolled in the SCES, and the baseline prevalence of different refractive errors, different behaviors associated with 1 year myopic shifts, and the different patterns of 2-year myopia progression between internal migrant and local resident school children have been analyzed. In some subset samples of the SCALE study and the SCES, several refraction components such as choroidal thickness (ChT) and crystalline lens power were also measured, to further elucidate the relationships between the refraction components and myopia as well as the mechanism of myopia incidence and development. The three methods used in Shanghai to prevent and intervene with childhood myopia: increasing outdoor time, low concentration atropine, and use of orthokeratology lens are also addressed in this review.
