what causes the pupils in your eyes to become smaller?

Answer 1

coke

Answer 2

well this is how it is cause :The size of the potential patient's naturally dilated pupils may be very important because of the possibility of halos, starbursts, and other undesirable effects after all laser assisted and non-laser refractive surgery. When they occur, pupil size related aberrations can range from a minor nuisance to transient debilitation, including the inability to drive at night. Laser assisted refractive surgery techniques conventional and wavefront Lasik, IntraLasik, PRK, LASEK, and Epi-Lasik for myopia are discussed here, however the issues regarding pupil size are important to all refractive surgery techniques, including RLE, P-IOL, and CK and all refractive errors, including myopia and hyperopia.

There are three major factors to consider with laser assisted refractive surgery for myopia.

1) Size of laser ablation treatment including the optical zone and transition zone compared to the patient's naturally dilated pupil.
2) Angle of the transition zone.
3) Amount of correction required.
There are many other factors that are considered regarding this issue, but we will focus on these primary three.

Not All Is "Seen"
It is important to remember that not all light reaches the retina and is "seen". The iris restricts, causing the pupil to be smaller, reducing the light reaching the retina, and thereby restricts the area on the cornea through which the light travels that reaches the retina and is seen. In bright light the iris makes the pupil smaller, allowing less light and only light through a small central area of the cornea to reach the retina. Most humans have optimal vision with about a 3.5mm pupil size. In low light, the iris enlarges the pupil, allowing light through the outer edges of the cornea through the pupil, reaching the retina.

Answer 3

Constriction is a safety feature of your eyes to prevent blindness from too bright light entering your pupils. Your pupils will also contract when trying to focus on far objects...much like the lense of a camera. In dark rooms, your pupils will dilate to enable you to see better. The average diameter of pupils should be 4 to 5 mm. With serious head injuries, the pupils will become unequal. Sometimes in the elderly the puils will constrict. Also in people with photophobia, or intolerance to bright lights. Drug usage can cause constriction also. Dilation of t he pupil may occur in blindness, distress, coma, strong emotion, fever, nerve paralysis and glaucoma. Cocaine, atropine, and other drugs may cause dilation of the pupils.

Answer 4

Bright lights or certain drugs can cause the pupils to become smaller.

Answer 5

Changes in light cause your pupils to grow or shrink. In low light situations, the pupils become bigger to absorb more light. In bright light, they contract to let less light in.

Answer 6

When the pupils are exposed to more light they are basically adjusting or focusing if you will to adjust to the new environment.

Answer 7

There are muscles in the iris that constrict and dilate the pupil.

Answer 8

the amount of light around you means your eyes require less light to see. Its kind of like a built in set of sunglasses

Answer 9

involuntary reaction to increases light. Also happens when you don't see things you like, France getting a penalty kick in the WC that they didn't deserve for example

Answer 10

top allow more light in to see better ur eyes get bigger. to allow less light ur eyes get smaller.

Answer 11

Exposure to light.