Science (The Eye)

What is light?

A form of energy that can be detected by the eye.

What distinguishes luminous objects from non-luminous objects?

Luminous objects produce their own light, while non-luminous objects reflect light.

How do light rays travel?

In straight lines, defined as the direction of light's path.

What is a light beam?

A stream of light represented by multiple rays.

What shape are convex lenses?

Fatter in the middle than at the edges.

What happens to light in a concave lens?

Light diverges, spreading out the beam.

What is the focal point of a convex lens?

The point where light beams converge.

What is the principal axis of a lens?

The line through the center of the lens, perpendicular to it.

What is required for the brain to see a clear image?

A clear image must be focused on the retina.

How do the cornea and lens work together?

The cornea bends light, while the lens makes fine adjustments.

What is accommodation in the eye?

The lens changes shape to focus light from different distances.

What role do ciliary muscles play in vision?

They adjust the shape of the lens for focusing.

What is the function of the retina?

It converts light energy into electrical impulses for the brain.

What is the blind spot in the eye?

The area where the optic nerve exits, lacking light-sensitive cells.

What does the aqueous humour do?

Nourishes the cornea and lens, maintaining eye shape.

What is the fovea?

The most sensitive part of the retina, focused on light.

What controls the size of the pupil?

Muscles in the iris adjust pupil size based on light intensity.

How does the pupil respond in strong light?

The iris contracts to make the pupil smaller.

What happens to the pupil in dim light?

The iris widens to allow more light to enter.

What muscles are involved in pupil size adjustment?

Circular and radial muscles in the iris control size.

What is the role of Vitamin A for the eyes?

Essential for maintaining healthy cells and night vision.

Which foods are rich in Vitamin A?

Liver, carrots, and spinach are good sources.

What should be done to protect the eyes from injury?

Wear sunglasses and goggles during risky activities.

What is long sight (hyperopia)?

Difficulty focusing on near objects due to light focusing behind the retina.

How is long sight corrected?

By using converging (convex) lenses.

What is short sight (myopia)?

Difficulty focusing on distant objects due to light focusing in front of the retina.

How is short sight corrected?

By using diverging (concave) lenses.

What causes astigmatism?

Irregular curvature of the lens or cornea affecting light focus.

How can astigmatism be corrected?

Using cylindrical lenses that work on one axis.

What happens in cataracts?

The lens becomes opaque, blocking light from reaching the retina.

How are cataracts treated?

Surgery to remove or replace the lens.

What is glaucoma?

Increased eye pressure due to blocked fluid drainage.

What can untreated glaucoma lead to?

Damage to the optic nerve and potential blindness.

How is glaucoma treated?

With eye drops, laser treatment, or surgery.

What is presbyopia?

Difficulty seeing near objects due to loss of lens elasticity with age.

How is presbyopia corrected?

By using converging lenses for near vision.