Lens accommodation
Accommodation – Focusing the lens of the eye by changing the curvature of the lens as a result of the contraction of the muscles that surround it. Accommodation of the lens of the eye allows a person to see sharply when looking at different distances. Relative.But when we look at a close object, further refraction and focus by the lens is needed.
Refractive anomaly is a professional term that describes the defect in the focus of the light rays reaching the retina. The role of the optical system in the eye (cornea and lens) is to produce a visual image projected at the back of the eye onto the retina. When there is no coordination between the optical power and the distance to the retina, no clear image is created and there is a refractive anomaly. If the optical power (cornea and lens) is too strong there is myopia, if it is too weak there is farsightedness and if there is asymmetric power there is astigmatism.
Creating a clear image on the retina is the first step in the visual pathway, in order to get normal vision, the receptors, the neural pathway and the transmission of information to the brain and pathways in the brain are also required to function properly, in order to decipher the message that reaches vision. The term “visual impairment” describes a condition in which vision cannot be improved to an optimal condition by glasses. In these cases, there may be defects in the tissues of the eye or a brain structure that restricts vision. Sometimes the need for glasses is part of the defect and sometimes even a delay in diagnosing the need for glasses can cause impaired vision development and vision pathways in the brain. Farsightedness Hyperopia When the rays of light come from a nearby point, they are not concentrated on the retina but behind it, so that the person cannot clearly see close objects. Distant objects are relatively clearly visible. Myopia may be caused by a short eyeball, either due to the non-curvature of the cornea or due to poor lens shape. This is usually a birth defect. Myopia A state of defect in the refraction of light rays caused by the inability of the lens to concentrate the light on the retina. Myopia is manifested by focusing the bone observed in front of the retina. Thus close objects are clearly visible, while distant objects appear blurred. Astigmatism The force of our eye should be symmetrical. In astigmatism, a situation arises in which the eye has two forces on different levels. Fix it by repairing with two forces in different planes (cylinder) and then there is a prescription for more complex glasses, such as: + 1.00-2.00X180 In general, a deviation in refraction alone will not cause significant vision impairment because the deviation can be “corrected” with glasses. Sometimes, a delay in diagnosis can cause significant vision impairment and then both glasses and work and rehabilitative treatment are needed. In children with visual impairments, the need for glasses can add another degree of difficulty in visual function due to various reasons For example: 1. Baby after cataract surgery. In surgery, remove the lens of the eye (cloudy lens = cataract) which has an optical power of about 20 diopters. Therefore, the eye lacks a lot of power and very high plus glasses are needed. Vision through such glasses is less natural and distorted with narrowing of field of vision and magnification. These problems do not exist in the repair of a contact lens so it is usually better to have contact lenses over glasses. If the cataract was only in one eye a contact lens is required to allow a combination of two eyes simultaneously. In such a case despite the medical and optometric treatment (surgery + contact lenses) there is still a visual impairment due to the damage to the development of vision caused by the cataract before its removal. This is where the ELI Association and Rehabilitation Treatment for the Preservation and Development of Vision enters the picture. Adding intense both visual and multi-sensory stimulation in order to develop normal vision in the cerebral plane. 2. albinism Albinism usually causes visual impairment. In most cases there is significant astigmatism and also tingling of the eyes (nystagmus). In all cases there is hypersensitivity to light. The need for glasses exists and providing glasses usually helps, but it does not solve the problem. Ned adjustments Permission in the environment, such as, proper lighting, use of appropriate contrast (contrast) and proper size of shapes and letters is required in order to improve vision abilities. Visual enrichment and multi-sensory stimulation are also needed to enable the normal development of the toddler and child.