An object that can focus light rays. In the eye, it brings light rays to focus on the retina.

The back of the eye which senses light brightness and colour.

The process of bringing light rays together to converge at a single point creating a clear image.

Occurs when light travels from one transparent medium to another, causing a change in direction.

Common defects of the human eye

Biology

Pupils will learn how hormones and glands of the human endocrine system enable us to coordinate and control changes in our bodies.

Pupils learned how substances essential for chemical reactions in living cells, and the products of the reactions, are transported into, around and out of the human body, and the implications of surface area:volume ratio.

Coordination and control: the human nervous system

Able to see things clearly far away, but objects close up appear blurred.

Able to see things clearly close up, but objects further away appear blurred.

Objects close up and also objects further away both appear blurred.

Which of the following statements describes short-sightedness?

A concave lens can be used to correct vision.

A convex lens can be used to correct vision.

Without glasses, the focal point is past the retina.

Long-sightedness can occur when the lens stiffens.

Long-sightedness can occur when the eyeball is elongated.

Which of these statements are true about long-sightedness? 

What part of the eye is replaced during a cataract operation?

A patient has an elongated eyeball. Select the condition they are most likely to have and the type of lens that could be used to correct the defect.

The sister is a carrier of red-green colour blindness.

Two siblings are tested for the red-green colour blindness gene. The sister's phenotype is Rr and the brother's phenotype is r. 
Which of the following statements are correct about the siblings?

Match the part of the eye to its function. 

Starting with the light entering the eye, put the following steps in order to describe how we see.

Which part of the eye changes size to control how much light enters the eye?

when the ciliary muscles relax to focus on objects that are far away

when the ciliary muscles contract to focus on objects that are near

Match the description of the lens to the object it is focusing on.

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