A cataract, usually happens normally.
Myopia often happens for two problems, because the cornea is very curve and thus very powerful or because the eye is too long or too large, which makes the focal point within the eye is greater.
Astigmatism is one of the main problems of blur eye. It is because an irregularity of the cornea, rather than being spherical, is oval, which disables the function of focusing.
Macular Degeneration Age-related impairment is degeneration of the macula or by the passage of time is divided into dry and wet. Your symptoms start with the loss of adaptation to changes in lighting and fine color perception.
Initial symptoms of presbyopia usually become apparent in reading being necessary to remove some text, increase the font size for reading and require good lighting to achieve the near approach.