Y do u keep ur eye open (which is covered by Construction paper) in snellen test?

Question

IF the letters appear blurred does it help to squint?
would covering the eye with your hand have the same effect as construction paper?
Y would u not feel upside down in space?
Y's it important to have insensitive and sensitive areas in your skin??


I need the answers urgent.........i know these questions sound dumb.............buh i hav no way out!!!!

Answer 1

It is harder to focus the uncovered eye on the target if the covered one is closed. I would think that hand and construction paper give same results. the doctor's office uses paper or plastic covering because otherwise yo might peek past your hand,

i don't think there are any insensitive areas on your skin (unless you have some scars from burns on your skin).

Answer 2

I have never been tought that you have to keep your covered eye open in the Snellen test so perhaps it's something to do with the way the brain percieves images. Covering with the hand has the exact same effect, make shift is the order of the day when you have nothing else.

It helps to squint as you narrow the beam of light that is coming into the eye and that will make the light focus better on the back of the eye.

You feel upside down on earth because the cells in your ear sense where you are in space, and the gravitational force tells your brain that your head in the wrong way up. In space there is no gravitational pull so your brain never gets a signal that there is a right and wrong way up, so you never feel upside down,

The reson there are areas of greater and lesser sensitiviy on the skin is due to the fact that it is more important to feel better on certain areas of the skin. For example, the lips and hands are very sensitive as they are used for felling the world a lot. Yet, if you take the back, then you need to feel stuff there, but not to a great extent, so it is less sensitive.

Answer 3

For the eye test the answer is simple. If you close the blocked eye it will be blurred when you switch over due to lacrimal fluid. Squinting may help, but it's cheating.
Since there is no gravity in space the fluid in your inner-ear will not settle in any one area, thus no sense of up/down.
Yes the sensitivity is important. The level directly effects the brains response to the stimuli. If you can't feel it, you won't know when it hurts. Imagine sex without any stimulation....pretty boring!