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: The Guangzhou Twin Eye Study (GTES) is a population-based study of young twins residing in Guangzhou City. The major aim of GTES is to explore the impact of genes, environmental factors and gene-environment interactions on common eye diseases. From 2006, for more than 1,300 twin pairs, age 7–26 years old, progressive ocular phenotypes, such as refraction, ocular biometrics, weight, and height were collected annually, while non-progressive phenotypes such as parental refraction, corneal thickness, retinal fundus, intraocular pressure and DNA only collected at baseline. In the current study, we summarize the major findings on the etiology of myopia in recent decades.
Abstract: This submission will briefly review the anatomy and physiology of the optic nerve, and highlight various ischemic optic neuropathies including anterior ischemic optic neuropathies (non-arteritis and arteritic), diabetic papillopathy, posterior ischemic optic neuropathies, and ischemic optic neuropathies in the setting of hemodynamic compromise.
Abstract: Acute retinal arterial ischemia, which includes transient monocular vision loss (TMVL), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and ophthalmic artery occlusion (OAO), is most commonly the consequence of an embolic phenomenon from the ipsilateral carotid artery, heart or aortic arch, leading to partial or complete occlusion of the central retinal artery (CRA) or its branches. Acute retinal arterial ischemia is the ocular equivalent of acute cerebral ischemia and is an ophthalmic and medical emergency. Patients with acute retinal arterial ischemia are at a high risk of having further vascular events, such as subsequent strokes and myocardial infarctions (MIs). Therefore, prompt diagnosis and urgent referral to appropriate specialists and centers is necessary for further work-up (such as brain magnetic resonance imaging with diffusion weighted imaging, vascular imaging, and cardiac monitoring and imaging) and potential treatment of an urgent etiology (e.g., carotid dissection or critical carotid artery stenosis). Since there are no proven, effective treatments to improve visual outcome following permanent retinal arterial ischemia (central or branch retinal artery occlusion), treatment must focus on secondary prevention measures to decrease the likelihood of subsequent ischemic events.
Abstract: Optical coherence tomography (OCT) is an ocular imaging technique that can complement the neuro-ophthalmic assessment, and inform our understanding regarding functional consequences of neuroaxonal injury in the afferent visual pathway. Indeed, OCT has emerged as a surrogate end-point in the diagnosis and follow up of several demyelinating syndromes of the central nervous system (CNS), including optic neuritis (ON) associated with: multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies. Recent advancements in enhanced depth imaging (EDI) OCT have distinguished this technique as a new gold standard in the diagnosis of optic disc drusen (ODD). Moreover, OCT may enhance our ability to distinguish cases of papilledema from pseudopapilledema caused by ODD. In the setting of idiopathic intracranial hypertension (IIH), OCT has shown benefit in tracking responses to treatment, with respect to reduced retinal nerve fiber layer (RNFL) measures and morphological changes in the angling of Bruch’s membrane. Longitudinal follow up of OCT measured ganglion cell-inner plexiform layer thickness may be of particular value in managing IIH patients who have secondary optic atrophy. Causes of compressive optic neuropathies may be readily diagnosed with OCT, even in the absence of overt visual field defects. Furthermore, OCT values may offer some prognostic value in predicting post-operative outcomes in these patients. Finally, OCT can be indispensable in differentiating optic neuropathies from retinal diseases in patients presenting with vision loss, and an unrevealing fundus examination. In this review, our over-arching goal is to highlight the potential role of OCT, as an ancillary investigation, in the diagnosis and management of various optic nerve disorders.
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.
Abstract: Genetic studies have revealed that variants in genes that encode regulators of the complement system are major risk factors for the development of age-related macular degeneration (AMD). The biochemical consequences of the common polymorphism in complement factor H (Tyr402His) include increased formation of the membrane attack complex (MAC), which is deposited at the level of the inner choroid and choriocapillaris. Whereas the MAC is normally protective against foreign pathogens, it can also damage resident bystander cells when it is insufficiently regulated. Indeed, human maculas with early AMD show loss of endothelial cells in the choriocapillaris, the principal site of MAC activation. Modeling of MAC injury of choroidal endothelial cells in vitro reveals that these cells are susceptible to cell lysis by the MAC, and that unlysed cells alter their gene expression profile to undergo a pro-angiogenic phenotype that includes increased expression of matrix metalloproteinase-9. Strategies for protecting choriocapillaris endothelial cells from MAC-mediated lysis and for replacing lysed endothelial cells will be discussed.
Abstract: Complications of myopia have become an important public health issue with serious socio-economic burdens. Prevention and treatment are both important. The Taiwan Student Vision Care Program (TSVCP) promoted by Ministry of Education (MOE) has been carried out for 3 decades in Taiwan. The myopia prevalence has increased rapidly to a high level and therefore myopia prevention has continued to be the most important item in the program. Therefore, TSVCP aims to decrease the prevalence of myopia, in order to decrease the high myopia related blindness in the future. Recently, outdoor activity has been found to be an important protective factor for myopia and was implemented in TSVCP since 2010. Afterwards, the nationwide vision impairment rate (uncorrected vision 20/25 or less) of elementary school students declined unprecedentedly and continuously in recent years. Evidence-based protective and risk factors for myopia are now clearer. Widespread acknowledgement of myopic disease, preventing the onset of myopia, prompt diagnosis, and early treatment to control progression are all important.
Abstract: Retinopathy of prematurity (ROP) is an emerging cause of childhood blindness in the developing countries. The low and middle-income countries are facing common challenges in the midst of the ‘third epidemic’ of ROP. Improvement in neonatal care facilities has increased survival of preterm babies. Lack of awareness and non-uniform standards of care in the ever-increasing number of neonatal intensive care units (NICUs) and special newborn care units (SNCUs) has resulted in this surge of ROP. Apart from low birth weight and the degree of prematurity, use of unblended supplemental oxygen, sepsis, anemia and blood transfusion are important risk factors associated with ROP in developing countries. Atypical forms of aggressive posterior ROP (APROP) are seen in heavier birth weight babies in the developing countries. Prevention of ROP by good quality neonatal care, timely diagnosis by mandatory ROP screening in NICUs and training manpower for laser treatment of ROP requires close collaboration between the neonatologists, ophthalmologists and the policy makers. Team approach and inter-disciplinary co-ordination are keys in a nation’s drive to fight this preventable cause of blindness.