Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How is the amount of light entering the eye controlled?
The amount of light entering the eye is controlled by the iris. It automatically changes the radius of the pupil to adjusts the size of the pupil according to the intensity of light received by the eye.
If the amount of light received by the eye is large (as during the daytime), then the iris contracts the pupil and reduces the amount of light entering the eye so that too much light can't cause glare and discomfort to the eye, and even can't damage the lens and retina.
If the amount of light received by the eye is small (as during the night or in a dark room) then the iris expands the pupil so that more light may enter the eye and make us able to see in dim or dark surroundings.
Explanation
Pupil is a hole in the middle of the iris, which appears black because the light that passes through it, gets absorbed by the retina and is not reflected back. Its function is to control the amount of light entering the eye with the help of the iris so that it can be focused on the retina to begin the process of sight.
Iris is the coloured part of our eye (typically brown or blue), which is made up of pigment and consists of two sets of smooth muscles that control the diameter and shape of the pupil, and they are:
1. Sphincter muscle - These muscles are in the shape of a ring located at the edge of the pupil and cause the iris to constrict or contract, reducing the size of the pupil.
If the light is bright, the size of the Pupil gets reduced (smaller), so that less amount of light can enter the eyes.
2. Dilator muscle - These muscles are in the radial shape located radially throughout the iris, like spokes on a wheel, and cause the iris to dilates or stretch, increasing the size of the pupil.
If the light is dim, the size of the Pupil gets increases (larger), so that more amount of light can enter the eyes.
218 Views
