Eye Diagram

Introduction

• Our body has five basic sense organs, and the eye is one of them.
• It has a layer known as the retina that contains receptor cells.
• The receptor cells in the retina are of two types: Cones and Rods.
• It is with the help of the eye that we can see various objects, colors, and lights.

Diagram of the Eye

Eye Parts and Functions

Adaptation in the Eye

• The process in which the retina and pupil adjust according to varying light intensities that fall on the eye is called Adaptation.
• In Dim Light, the pupils dilate to allow more light to enter, and the rod cells in the retina become more active.
• These adjustments enable correct vision in low light.
• In Bright Light, the retina interprets high-intensity light and sends signals to the brain. The brain, in response, constricts the pupils.
• With this, potential damage to the retina is prohibited.

Accommodation in the Eye

• The natural ability of the eye to change its lens’s shape to adjust its focus so that objects at different distances can be seen clearly is called Accommodation.

How Does The Eye Focus on a Near Object?

• To see a near-placed object clearly, the eye must increase its focusing power.
• For this, the ciliary muscles contract, loosening up the suspensory ligaments.
• This makes the lens fat and more curved.
• Therefore, light rays refract more and focus on the retina.

How Does The Eye Focus on a Distant Object?

• To see a distant object clearly, the eye must reduce its focusing power.
• For this, the ciliary muscles relax, tightening the suspensory ligaments.
• This makes the lens thinner and less curved.
• Thus, light rays refract less and focus on the retina.

Defects of the Eye

• Myopia (Short-sightedness) is the condition in which objects placed at a distance appear faded.
• This happens because the rays of light focus before the retina.

• Lengthy eyeball or Extra-curved cornea.
• The patients suffering from this condition are short-sighted or myopic.

• Hyperopia/Hypermetropia (Long-sightedness) is the condition in which objects placed nearby appear blurred.
• This happens when the rays of light focus behind the retina.

• Small eyeball or less curved cornea.
• The patients suffering from this condition are long-sighted or hyperopic or hypermetropic.

Treating Eye Defects

• Correction of Myopia is done with a diverging lens.
• The rays of light are diverged so that after refraction from the eye lens, they focus on the retina, not in front of it.

• Correction of Hyperopia is done with a converging lens.
• The rays of light are converged so that after refraction from the eye lens, they focus on the retina, not behind it.

Frequently Asked Questions