Defects of refractive vision
About 50% of people around the world suffer from visual impairment or weakness, which can be corrected using LASIK operations and correcting vision.
The most important of these defects:
- Myopia appears when the convex cornea or the distance between the lens of the eye and retina is shorter than normal. Thus, the light accumulates in front of the retina rather than directly gathering on its surface, resulting in blurred vision when looking at distant objects.
- the length of vision occurs when the cornea is flat or when the distance between the lens of the eye and retina is longer than normal. And therefore The light accumulates behind the retina, leading to blurred vision when looking at nearby objects.
- Astigmatism occurs when the surface of the cornea is irregularly curved such as the back of the spoon instead of being regularly convex as the clock bottle. This means that light is collected at several points on the retina resulting in blurred vision.