The visual impairment
When the eye is healthy, light reaches the retina without any obstacles. The brain therefore receives a clear image. A failure in this process can lead to visual defects. The most common visual disorders are the myopia, hyperopia, astigmatism and presbyopia. People of all age groups can be affected namely, infants, children, adolescents, adults and seniors.
Your near vision is good but you face difficulty to see things from far. This defect, due to an eye either too long or too powerful, creates a big distance between the cornea and the retina. The image is blurred because it is formed too much forward of the retina.
Signs : You tend to squint your eyes to see from afar.
Solutions : Diverted or concave lenses, finer in the center and thick on the edges, will allow to reposition the image.
You see things better from far than near, you have hyperopia. This visual defect is due to an eye being too short or not powerful enough. The image are formed behind the retina and the brain receives a blurred image.
Signs : You experience eye strain and headaches especially in the evening and after work because your eye is forced to make an effort to adjust to its environment. If it is a major defect, it can be coupled with a strabismus.
Solutions : Convergent or convex lenses that are thicker in the center can channel the magnified image and bring it closer to the retina. Your glasses then have a magnifying effect.
Your vision is blurred, inaccurate, distorted or even split at all distances due to a slight defect in the curvature of the cornea and, or the lens. The distant and near vision is distorted by the fact that the image is formed in the back and front of the retina.
Signs : You confuse figures or similar letters such as H and M, 0 and 8. Astigmatism can also be combined with myopia, hyperopia and, or presbyopia.
Solutions : Wearing toric or cylindrical lenses compensates for this defect in the cornea and, or the lens.
The signs of presbyopia can be seen as from forty years. It is not a visual defect but rather the effects of the aging of the lens which, over the years, loses its elasticity. Presbyopia is the natural evolution of vision and can come with myopia, astigmatism and / or hyperopia.
Signs : The first distinctive sign is the difficulty to see things that are near. You may also feel that there is not enough light to read comfortably.
Solutions : Several solutions exist to correct presbyopia. Simple reading lenses for close-up vision, mid-range lenses for close-up viewing, and progressive lenses that remain the most comfortable solution, allowing the wearer to regain a natural view .