From the physiological point of view blindness can be defined as the state of sight deficiency. However, the definition, as it is applied to people who are legally classified as blind, is more complex. Total blindness is a permanent and complete loss of sight when the visually handicapped person cannot perceive the light. The significant decrease of vision functions is labeled as practical blindness.
A serious eyesight disorder - blindness has many causes:
From the physiological point of view blindness can be defined as the state of sight deficiency. However, the definition, as it is applied to people who are legally classified as blind, is more complex. Total blindness is a permanent and complete loss of sight when the visually handicapped person cannot perceive the light. The significant decrease of vision functions is labeled as practical blindness.