Free Radicals, Antioxidants and Eye Diseases: Evidence from Epidemiological Studies on Cataract and Age-Related Macular Degeneration

2010 ◽  
Vol 44 (3) ◽  
pp. 191-198 ◽  
Author(s):  
A.E. Fletcher
2011 ◽  
Vol 70 (4) ◽  
Author(s):  
O. A. Oduntan ◽  
K. P. Masige

Free radicals, referred to as oxidants are molecules in the body with unpaired electrons, hence are unstable and ready to bond with other molecules with unpaired electrons.  They include Reactive Oxygen Species (ROS) such as superoxide anion radicals (·O¯), hydrogen peroxide (H202), and hydroxyl free radicals (·OH).  Endogenous sources of ROS include metabolic and other organic processes, while exogenous sources include ultraviolet radiation and environmental toxins such as smoke.  Antioxidants (oxidant scavengers) such as ascorbate, alpha-tocopherol and glutathione as well as various enzymatic compounds such as superoxide dismutase (SOD), catalase and glutathione reductase are also present in the body and in manyfoods or food supplements.  An imbalance between oxidants and antioxidants in favour of oxidantsis termed oxidative stress and can lead to cell or tissue damage and aging. Oxidative stress has been implicated in the pathogenesis of many serious systemic diseases such as diabetes, cancer and neurological disorders.  Also, laboratory and epidemiological studies have implicated oxidative stress in the pathogenesis of the majority of common serious eye diseases such as cataract, primary open angle glaucoma and age-related macular degeneration. In this article, we reviewed the current information on the roles of oxidative stress in the pathogenesis of various eye diseases and the probable roles of antioxidants.  Eye care practitioners will find this article useful as it provides information on the pathogenesis of common eye diseases. (S Afr Optom 2011 70(4) 182-190)


2020 ◽  
Vol 8 ◽  
pp. 205031212094304
Author(s):  
Perseus WF Wong ◽  
Jordy KP Lau ◽  
Bonnie NK Choy ◽  
Kendrick C Shih ◽  
Alex LK Ng ◽  
...  

Objectives: To assess the proportions of respondents in the general community having heard or awareness, and their knowledge level, of three common eye diseases: age-related macular degeneration, cataract, and glaucoma. We also attempted to assess for risk factors that may be associated with any variations, which will help identify the areas of inadequate knowledge and demographics of potential audiences for focused health education. Methods: We conducted a community-based pilot survey for the residents from a southern suburb of Hong Kong in early 2016, by inviting all aged 50 or above to complete a standardized questionnaire in the local community hall. Results: Most of the 222 respondents have heard, or awareness, of cataract (92.79% or 81.98%, respectively), followed by glaucoma (86.94% or 52.70%, respectively), and age-related macular degeneration (51.35% or 29.28%, respectively). The results of Cronbach’s alpha (α > 0.7) and Spearman’s correlation coefficient (p < 0.01) suggested that the internal consistency, convergent and discriminant validities of the questionnaire were acceptable for the study population. Compared to a previous Hong Kong survey in 2002, the proportions of having heard of the three eye diseases were greater, but the overall knowledge remained limited. From a maximum knowledge score of 29, the median scores for age-related macular degeneration, cataract, and glaucoma were 9, 13, and 14, respectively. Except for the treatment of cataract, the knowledge level in most areas was low. Sociodemographic factors and medical history, rather than behavioral factors, were more likely to be associated with having a higher knowledge level. Subjects with family or friends with a history of glaucoma or age-related macular degeneration were more aware and knowledgeable, but not for subjects who were current and past smokers or alcohol drinkers. For age-related macular degeneration, gender modified the effect between age and knowledge level, while age was a confounder of having medical history, and having heard or awareness, of the disease. Conclusion: Despite a larger proportion of the community having heard or awareness since 15 years ago, much effort remains for improving health knowledge of these three eye diseases in Hong Kong. We recommend targeting respondents with higher lifestyle risks, such as current and past smokers or alcohol drinkers, as a focused audience, and utilizing family members, relatives, or friends as another way of distributing health information.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Martina Barchitta ◽  
Andrea Maugeri

Age-related macular degeneration (AMD) is the most common cause of blindness in elderly people worldwide and the major degenerative disease of the retina that leads to progressive impairment of central vision. Several polymorphisms in different genes have been proposed as factors that increase the disease susceptibility. The aim of the present study is to carry out a systematic review and an updated meta-analysis in order to summarize the current published studies and to evaluate the associations between four common vascular endothelial growth factor (VEGF) polymorphisms (rs833061, rs1413711, rs3025039, and rs2010963) and AMD risk, also stratifying for AMD subtypes and ethnicity. A systematic literature search in the Medline database, using PubMed, was carried out for epidemiological studies, published before June 2016. Associations ofVEGFpolymorphisms with AMD were estimated by calculating pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) based on different models. Twelve articles were included in the analysis. The present meta-analysis constitutes a useful guide for readers to study AMD and adds new evidence to the growing literature on the role ofVEGFpolymorphisms in the risk of AMD. Significant associations with AMD risk were showed for rs833061, rs1413711, and rs3025039 polymorphisms but not for rs2010963.


Author(s):  
Jae-Hwan Lee ◽  
Ramana M. Pidaparti

New drugs for curing eye diseases have been developing for a decade and are very unique for each eye diseases such as glaucoma, cataracts, and age-related macular degeneration (AMD). It is estimated that 1.6 million adults in the US over the age of 50 and above suffer from age-related macular degeneration and about 200,000 cases are diagnosed annually. Worldwide, about 500,000 cases are diagnosed annually [1]. Drugs currently utilized for AMD are delivered via repeated intravitreal injections of the drug into the eye. Risks of repeated intravitreal injections can include intraocular infections (endophthalmitis), intraocular hemorrhage, and retinal detachment. Also, reducing the frequency of dosing will clearly benefit the patient by reducing the need for risky intravitreal injections and improving the pharmacokinetics of the drug in the eye. The eye disease of posterior segment (Dry and Wet) has limits to deliver the drug to retina region using typical eye drop. The drug injection using a needle with syringe can deliver but it barely provide right amount of doses, or over doses that may cause more severe problem such as swelling, fatigue, and damaging photoreceptor molecules. Furthermore, most drugs run away in a month so that repeated injection is necessary. Developing an implantable drug delivery device will help reduce the costs and risks associated with frequent injections and facilitate delivering the drug in a controlled manner and in the required amounts, and improve therapeutic efficacy and safety of drugs. This study focuses on the design, simulation and development of the implantable ocular drug delivery device.


Choroidal neovascularization is defined as the formation of new blood vessels located between the retinal pigment epithelium and the Bruch's membrane. The neovascular structure is taken origin from the choroid, crosses the Bruch membrane, and affects the photoreceptors with RPE. It is most frequently observed in Age-Related Macular Degeneration and less frequently in other eye diseases. This review mentions choroidal neovascularization and its causes as a general.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sara Velilla ◽  
José Javier García-Medina ◽  
Alfredo García-Layana ◽  
Rosa Dolz-Marco ◽  
Sheila Pons-Vázquez ◽  
...  

Age-related macular degeneration (AMD) is one of the main socioeconomical health issues worldwide. AMD has a multifactorial etiology with a variety of risk factors. Smoking is the most important modifiable risk factor for AMD development and progression. The present review summarizes the epidemiological studies evaluating the association between smoking and AMD, the mechanisms through which smoking induces damage to the chorioretinal tissues, and the relevance of advising patients to quit smoking for their visual health.


2021 ◽  
Vol 13 ◽  
pp. 251584142110304
Author(s):  
Mousumi Banerjee ◽  
Rohan Chawla ◽  
Atul Kumar

Age-related macular degeneration (ARMD) is one of the prominent causes of central visual loss in the older age group in the urbanized, industrialized world. In recent years, many epidemiological studies and clinical trials have evaluated the role of antioxidants and micronutrients to prevent the progression of ARMD. In this article, we review some of these major studies. In addition, we review the absorption and bioavailability and possible undesirable effects of these nutrients after ingestion. The role of genotypes and inappropriate use of these supplements are also discussed. From all the above evidence, we conclude that it may not be prudent to prescribe these formulations without a proper assessment of the individual’s health and dietary status. The effectiveness of all the components in antioxidant formulations is controversial. Thus, these supplements should not be prescribed just for the purpose of providing patients some kind of therapy, which may give a false sense of mental satisfaction.


2021 ◽  
Vol 65 (1) ◽  
pp. 62-68
Author(s):  
Dmitry A. Konyaev ◽  
Evgenia B. Popova ◽  
Anton A. Titov ◽  
Nikolay M. Agarkov ◽  
Maksim M. Yablokov ◽  
...  

The priority problem of various industrial and developing countries, which largely determine the health of the population and, above all, older age groups, is currently eye diseases. Most modern researchers consider age-related macular degeneration, glaucoma, and cataracts to be eye diseases. Socially significant eye diseases have a high prevalence and are the leading cause of blindness in various countries. Authors analyzed the prevalence of glaucoma, age-related macular degeneration, and cataracts according to domestic and foreign publications in recent years. The results of the studies considered in the scientific review indicate a continuing gain in socially significant eye diseases, the frequency of which increases with age. The high incidence of the studied pathology is observed in China, India, and Russia. The study shows socially significant eye diseases to be the most critical problem in various countries, including the Russian Federation. The relevance of this pathology will increase due to the ongoing aging of the population and an increase in their share in the demographic structure of many states. The high prevalence of age-related macular degeneration, cataracts, and glaucoma leads to an increase in the number of people on the planet with complete or partial vision loss, which significantly disrupts their social functioning and requires significant financial costs for treatment and ensuring an acceptable level and quality of life. The data presented in the review and obtained results are of practical importance for the organization of monitoring of eye diseases and the development of an appropriate state and health strategy.


2021 ◽  
Vol 25 (2) ◽  
pp. 106-113
Author(s):  
T. A. Khalimov

Based on the analysis of published data, the review provides information on the role and mechanisms of angiogenesis in the development of eye diseases. It has been shown that the developing inflammatory process associated with infections or damage to the organ of vision almost always leads to the appearance of newly formed vessels in the avascular cornea. The progression, in particular, of age-related macular degeneration is associated with the immune-mediated development of angiogenesis processes. A key inducer of angiogenesis is vascular endothelial growth factor (VEGF), whose activity can be enhanced by a number of pro-inflammatory cytokines (tumor necrosis factor alpha, TNF-), growth (fibroblast growth factor, FGF) and transforming factors (transforming growth factor beta, TGF- ). In addition, VEGF overproduction is mediated by an imbalance of pro-angiogenic (angiogenin) and anti-angiogenic (angiostatin, vasostatin, endostatin; tissue inhibitors of matrix metalloproteinases) factors. Antiangiogenic activity based on inhibition of vascular endothelial growth factor (VEGF) has been successfully used in the treatment of a number of eye diseases, such as exudative age-related macular degeneration and diabetic macular edema, the pathogenesis of which is based on the growth of newly formed vessels. The review presents information on the main anti-angiogenic drugs for intravitreal administration, used in ophthalmology.


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