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Computer-Aided Cataract Detection Using MLP and SVM
Published in Puneet Kumar, Vinod Kumar Jain, Dharminder Kumar, Artificial Intelligence and Global Society, 2021
Simran Agarwal, Manish Kumar, Sunil Kumar Jangir, Chandraprakash Sharma
The eye is a significant organ in the human body. It includes interconnected subsystems like the lens, iris, retina, cornea, and optic nerve. There are many ocular disorders associated with different parts of the eye such as glaucoma, macular degeneration due to trachoma and aging, hereditary myopia, retinitis pigmentosa, and diabetic retinopathy but patients are not usually conscious of their progress. An ophthalmologist or optometrist detects eye disease through slit-lamp (retinal examination) or visual acuity checks after inspecting the pupil. Visual acuity tests are done using a chart or display device, interpreting a series of progressively smaller letters. Using an intense light line, an ophthalmologist can examine the eye under magnification. During retinal evaluation, the pupil is dilated with drops enlarging the lens to test eye motions and pupil response. These methods of screening require costly medical equipment that only an experienced ophthalmologist can use. Manual methods are also time-consuming and subjective to the experience of the ophthalmologist. In the past few years, the researcher has made so many attempts to detect eye disorders automatically. According to a WHO survey, the world’s estimated number of visually impaired people is 285 million — 39 million are blind and 246 million have damaged vision; 33% of visual impairment cases and 51% of blindness cases are caused by cataracts (Shaheen & Tariq, 2019).
Virtual Reality Applications in the Context of Low-Vision Rehabilitation
Published in Christopher M. Hayre, Dave J. Muller, Marcia J. Scherer, Virtual Reality in Health and Rehabilitation, 2020
Marie-Céline Lorenzini, Walter Wittich
Visual impairment is globally prevalent across the lifespan, affecting around 314 million people worldwide (Foster et al., 2008) and includes blindness and low vision (Alabdulkader and Leat, 2010). Low vision corresponds to mild or moderate visual impairment that is not correctable with glasses, contact lenses, or surgical interventions and interferes with normal everyday functioning (Corn and Lusk, 2010). The World Health Organization has established criteria for low vision which are used in the International Classification of Diseases (World Health Organization, 2018). Based on an estimate of visual loss in terms of impairment (describes how the eye/visual system functions), low vision is defined as a best-corrected visual acuity worse than 0.5 logMAR (Snellen fraction equivalent of 6/18 or 20/60) but equal to or better than 1.3 logMAR (6/120 or 20/400) in the better eye, or visual field loss corresponding to less than 20° in the horizontal or vertical plane in the better eye with best standard correction. In industrialized countries, older adults (75+ age group) constitute the fastest growing segment of the population with low vision (Margrain, 1999, Watson, 2001), whereby visual impairment has been ranked third (Vos et al., 2016), after anaemia and hearing loss, among conditions that cause people older than 70 years to require assistance in activities of daily living (Scott et al., 1999).
Vision and Visual Illusions
Published in Frank H Hawkins, Harry W Orlady, Human Factors in Flight, 2017
Frank H Hawkins, Harry W Orlady
Visual acuity can be affected by a number of factors such as brightness, brightness ratio and contrast, time to view the object and glare. Not only is glare a source of discomfort - it sometimes makes people feel tense and restless - but experiments have shown that visual performance is reduced. This depends on how close the glare source is to the line of sight. One study showed that with the glare source at 40° from the line of sight, the loss of visual effectiveness was 42%, while when only 5° away, the loss increased to 84%. The glare was half the level of the general illumination (Luckiesh et al., 1927). Sensitivity to glare increases with age. One of the most prevalent beliefs is that glare causes visual fatigue. Other effects claimed include psychological stress, fixation and disruption of accommodation. However, very few studies have attempted to assess these effects. In fact, there are no objective means for measuring visual fatigue and an experimenter would have to rely on subjective opinion. While there may be some substance in the many claims made, further studies are needed before definitive conclusions can be reached. Literature reviews of the subject are available (e.g. Koffler Group, 1985).
Accessibility Design Issues beyond the Standards of Government e-Services for People with Low Vision
Published in International Journal of Human–Computer Interaction, 2023
Aritz Sala, Myriam Arrue, J. Eduardo Pérez, Sandra M. Espín-Tello, Lourdes Moreno
The number of individuals living with some manner of disability has been steadily increasing all around the world. According to the World Health Organization (WHO), it is estimated that the percentage of the world’s over 60 year-old population will nearly double between 2015 and 2050 from 12 to 22% (WHO, 2022). A significant increase in disabilities due to the rise of chronic diseases caused by age-related issues in all areas of the globe has been predicted in the Global Burden of Disease study (IHME, 2017) carried out by the WHO and the World Bank. According to WHO estimates, around 246 million people worldwide are considered to have “low vision” (WHO, 2014). This impairment is found in individuals with a visual acuity of 20/70 in the eye with the healthiest vision and is one that cannot be corrected with glasses, contact lenses, medication, or surgery (Whittaker et al., 2016). Furthermore, the vision of a portion of this population is not stable and may degenerate even further over time.
The Influence of Vertical Illuminance on Cognitive Performance and Subjective Evaluations during Simulated Conditions of Polar-Night Specificity
Published in LEUKOS, 2023
Huiling Cai, Qingcheng Lin, Hanwei Liu, Maocang Tian, Xuefeng Li, Hui Xiao
Eligible individuals were healthy young people and provided informed consent. Potential participants were screened based on the following criteria: absence of diseases such as hypertension, diabetes, and heart disease; no color blindness or color weakness; normal or corrected-to-normal vision; not smokers or alcoholics; and all right handed. Vision is visual acuity, a physiological measure of how well the human eye can recognize the shape of small objects. When the human eye can distinguish two very close points, the angle formed between the two points and the human eye is the angle of view , with the unit of arc minute (1/60 ). The visual acuity = 1/. The visual acuities of the participants were checked by the Black Landolt C on the white background (D65, 100 cd/m2), which consists of a ring with a gap at various positions. Also, the participants were asked to perform color plate tests to measure for color blindness. They viewed an image made up of colored dots with a differently colored number or shape in the middle.
Evaluating the Visibility of Architectural Features for People with Low Vision – A Quantitative Approach
Published in LEUKOS, 2022
William B. Thompson, Robert A. Shakespeare, Siyun Liu, Sarah H. Creem-Regehr, Daniel J. Kersten, Gordon E. Legge
Low Vision refers to any long-term visual impairment, not correctable by glasses or contacts, which affects every day functioning. In more quantitative terms, low vision is often defined as visual acuity less than 20/40 (metric 6/12) or a visual field with a maximum extent of less than 20º in the better eye. Low vision refers to people with remaining functional vision and does not include people who are totally blind. Prevalence statistics on visual impairment usually combine low vision and total blindness. Of the 441.5 million visually-impaired people worldwide, the vast majority have low vision (Bourne et al. 2017). By recent estimates, there are about 5.7 million Americans with impaired vision, most of whom have low vision (Chan et al. 2018). Because the prevalence is high for older people, this number is expected to nearly double by 2050 (Chan et al. 2018).