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Age-Related Physiological Changes Influencing Work Ability
Published in Joanna Bugajska, Teresa Makowiec-Dąbrowska, Tomasz Kostka, Individual and Occupational Determinants, 2020
Several diseases that alter vision, more frequently experienced in advanced age include the following: Cataract: opacification of (normally clear) lens which can be either unilateral or bilateral.Age-related macular degeneration (AMD): central vision loss due to accumulation of deposits in the macula. There are two types of macular degeneration, namely the dry type and the wet type. It becomes the most common cause of blindness in advanced age.Glaucoma: amplification of intraocular pressure that may cause atrophy of the optic nerve.Diabetic and hypertensive retinopathy: damage of the retina due to a long-term and poorly controlled diabetes or hypertension.
Human-Centric/Integrative Lighting Design
Published in Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe, Visual and Non-Visual Effects of Light, 2020
Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe
The other very important issue is the potential hazard for the macula on the retina, which is very sensitive to blue light. The macula is a special area in the center of the retina which is responsible for visual acuity. Neither the retina nor the macula can be regenerated or replaced if damaged. Emerging research [Schen et al. 2016] suggests that cumulative and constant exposure to blue light can damage retinal cells and lead to age-related macular degeneration (AMD). It is important to note that the current regulations and standards related to blue light hazard evaluation have been established on the basis of acute light exposure and do not take into account the effects of repeated exposure [Krigel et al. 2016]. This should be considered if we want to use blue-enriched light for circadian stimulus every day.
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
To treat this condition, small photocoagulation burns by a green argon or diode laser can be peppered over the retina to cover regions damaged by leaking blood vessels. Figure 3.32 depicts the back of the retina, showing how many burns with diameters of several hundred microns are applied over a wide region of the retina, targeting the troublesome blood vessels and sparing normal ones. Each burn takes approximately one-tenth of a second, and hundreds are applied. While laser surgery for diabetic retinopathy cannot correct deterioration that has already occurred, it is frequently effective in preventing future losses. Several large studies of photocoagulation's effectiveness have shown that persons treated in this way are much less likely to suffer from severe vision loss. Even more dramatic improvements are seen in treating some cases of a related retinal disease, macular degeneration, with photocoagulation.
Automated system for detection and classification of cystoid macular oedema using OCT images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2023
Priyanka Kaushik, S. R. Nirmala
Macular oedema is a condition characterised by the accumulation of fluid in the macula, the central part of the retina which is responsible for sharp, detailed vision. The fluid accumulation leads to the swelling of the macula, causing disturbed vision and then to vision loss. For macular oedema detection, OCT imaging is preferred. The retina has several layers as shown in Figure 1. Each layer has its own unique structure and has a different response to light and hence different reflectivity. The OCT system works on imaging of reflected light. It provides high-resolution, cross-sectional images of the retina, allowing for detailed visualisation of the macular region (Huang et al. 1991). It provides information about the thickness and structural changes in the macula, which is essential for detection and classification of macular oedema. The OCT image obtained from the imaging device is shown in Figure 2.
An Empirical Comparison between the Effects of Normal and Low Vision on Kinematics of a Mouse-Mediated Pointing Movement
Published in International Journal of Human–Computer Interaction, 2022
Yuenkeen Cheong, Chen Ling, Randa Shehab
There are numerous causes of low vision. In many cases, it is pathological. Low vision is often caused by conditions, such as macular degeneration, cataracts, glaucoma, and diabetic retinopathy (Kraut, 2000). These conditions can result in a host of vision problems. Macular degeneration is a condition caused by deterioration of the central part of the retina that is responsible for visual acuity in central visual field. Cataracts are caused by clouding of the lens. Common cataracts-related conditions include blurred and hazy vision in highly illuminated environments. Glaucoma is caused by pressure buildup inside the eye that damages the optic nerve, which in turn causes loss of peripheral vision. Diabetic retinopathy is caused by leakage in retinal blood vessels. Blurred vision and increased sensitivity to glare are common problems associated with diabetic retinopathy. Note that conditions listed above are not exhaustive; they are only a fraction of conditions associated with low vision.
Detection of macular diseases in optical coherence tomography image
Published in International Journal of Parallel, Emergent and Distributed Systems, 2020
Xiaoming Liu, Zhou Yang, Wei Hu, Jun Liu, Kai Zhang
Many macular diseases can lead to vision decreasing or blindness such as macular edema, macular hole and age-related macular degeneration (shown in Figure 2). Macular edema [3] occurs when fluid and protein deposit on the macular and cause retina to thicken or swell. It can be classified into cystoid macular edema involving fluid accumulation in the outer plexiform layer, and diabetic macular edema caused by leaking macular capillaries. Macular hole [4] is a small break in the macular. The vitreous is a jelly-like substance in the eye, and it is usually adherent to retina. Along with the growth of age, vitreous get watery and begin to separate from the retinal surface. The higher the degree of attachment between vitreous and retina, the more likely macular hole is developed. Age-related macular degeneration [5] typically occurs in older people where the severity is divided into early, intermediate and late types. Drusen, which appear as a bulge, is an important clinical indicator for this disease, and it occurs at the neighbourhood of retinal pigment epithelium (RPE).