Question: How come people aren't born blind or deaf, but after time they become blind or deaf, or have bad eyesight or hearing? and i dont mean when they are old.

  1. First of all some people are unfortunately born blind or deaf.

    For the rest of us, the reasons people go blind or deaf later in life is because those systems get damaged. Both the sense of vision and the sense of hearing have complication systems that allow the brain the receive information about light (vision) or sound (hearing) and work out what is going on. If any part of that system is damaged it can result in loss of hearing or vision.

    Disease and injury can both cause loss of hearing and vision, but even without those people tend to loose some hearing and vision as they get older. This is really just those systems wearing out as you get older.

    In vision it is common for the lens of the eye to get harder as you get older. This means that it is harder for the eye to focus light onto the retina. Fortunately this can be fixed by using an external lens (glasses or contacts) to help the lens in the eye. Something else that is quite common is the eyeball can change shape, which changes where the eye need to focus the light. Again this is helped with glasses.

    With hearing, lots of people go deaf because they have been exposed to too much loud noise over their life, but even without that we all start going deaf when we are teenagers. Sound is made up of a range of frequencies, which are the high and low pitched sounds that we can hear. While we are teenagers the receptors in the ear that detect the very high frequencies start dying, then the next higher and so on for the rest of out lives. If you have a way to test it, you will find that you can hear higher pitched noises than your teachers, especially the older ones. Fortunately, most of the these high frequencies are not that important and we only start to notice that we are going deaf when we start to loose the important frequencies, like the ones responsible for hearing speech.

    There are other parts of these systems that can get damaged with old age, but those are the main ones I know about. It’s unfortunate that part of getting older is that the body deteriorates, but it’s how it is. All you can do is avoid things that help the deterioration along and hope that we discover a Fountain of Youth 🙂