Vision

Question 1

Name this definition:

This the external layer which is a mainly white, semi-rigid fibrous layer which provides the eye with its shape as well as protecting it from potential damage caused by blows or knocks to the head -

At the front of the eye, this layer becomes a transparent area in order to allow light to enter called the -

Answer 1

Sclera or sclerotic layer.

Cornea

Question 2

Name this definition:

This is a dark, pigmented layer containing blood vessels. It prevents light from reflecting within the eyeball and forms the iris around the pupil at the front of the eye.

Answer 2

The Choroid or middle layer.

Question 3

Name this definition:

This covers the inside of the eye and contains light-sensitive photo-receptor cells called -

Answer 3

The retina, or inner layer. Rods and cones.

Question 4

The main body of the eyeball is filled with a transparent jelly-like substance called -

Answer 4

vitreous humour

Question 5

The anterior chamber is found behind the -

Answer 5

Cornea

Question 6

The posterior chamber is found behind the -

Answer 6

iris

Question 7

The posterior and anterior chambers are filled with -

Answer 7

aqueous humour

Question 8

The cornea thickness?

Answer 8

10 - 12mm

Question 9

The conjunctiva is the -

Answer 9

thin, transparent tissue that covers the outer surface of the eye between to cornea and the eye lid.

Question 10

Name the definition:

Almond shaped apparatus which is located just above the eyes and supply the eyes with a salty substance, called tears, and which also contain a fluid which provides a degree of protection against infection.

Answer 10

Lacrimal Glands

Question 11

Name the definition:

This is a pigmented or coloured muscular membrane, situated behind the cornea and contains an aperture knows as the pupil. This is the first means of enabling the eye to adapt to changing light conditions.

Answer 11

The iris

Question 11

The anterior champer is

Question 12

In the case of poor light conditions the iris -

Causing the pupil to -

Answer 12

contracts

Dilate. The reverse applies to bright light conditions

Question 13

Name the definition:

located immediately behind the iris, this is composed of a transparent flexible material and is supported by the ciliary muscles which are used to changed its shape, thus enabling it to focus the light rays.

Answer 13

The lens

Question 14

To ability of the ciliary muscles to change the shape of the lens to achieve focus is called -

Answer 14

accommodation

Question 15

Name the definition:

This is a soft layer of light-sensitive nervous tissue, which covers the inside of the eye -

It contains two different types of photo-receptor cells, known as -

The area in the brain where nerve impulses from the retina is converted into sight -

Answer 15

The retina

rods and cones because of their
shape.

Visual cortex

Question 16

Rods or Cones:

These are highly sensitive to colour and function to define small detail as well as distant objects, provide the best visual acuity or accuracy(photopic vision).

maximum efficiency is achieved in conditions of good illumination. These or important for our central or foveal vision.

Answer 16

Cones

Question 17

Rods or Cones:

The primary function is to define movement, but not in detail and, having no
perception of colour, only in shades varying from black to white. Are able to function in dim light and instrumental in our peripheral vsion, the function of which is essential for both orientation and night vision(scotopic vision).

Answer 17

Rods

Question 18

Refraction is the ability of the -

Answer 18

Cornea and the lens to bend light rays in order to focus them on the retina

Question 19

Refraction is the ability of the _____ and the ___ to bend light rays in order to focus them on the retina to produce an image.

The 4 refractive errors -

Answer 19

Refraction is the ability of the cornea and the lens to bend light rays in order to focus them on the retina to produce an image.

1. Hypermetropia
2. Myopia
3. Astigmatism
   4 Presbyopia

Question 20

Hypermetropia(long sightedness) can be corrected using -

Answer 20

Convex lenses

Question 21

Myopia(short sightedness) can be corrected using -

Answer 21

Concave lenses

Question 22

Name the definition:

This is an optical effect caused primarily by unevenness of the curvature of the cornea and to a lesser extent, the lens, resulting in distorted images. This can be corrected by the use of various lenses.

Answer 22

Astigmatism

Question 23

Near vision deteriorates with age. This is called -

Answer 23

Presbyopia

Question 24

the focus of both eyes on an object simultaneously is called -

Answer 24

Stereoscopic vision

Question 25

Monocular Vision: Name the definition: Parallel lines, such as as railway lines, the edges of roads or runways, appear to converge with increasing distance from the observer

Answer 25

Linear Perspective

Question 25

Monocular Vision: Name the definition: Objects which are close appear to move past the observer, whilst distant objects appear to either move in the same direction as the observer or remain static.

Answer 25

Motion parallax

Question 25

Monocular Vision: Name the definition: It follows that the closer the object is to the observer, the larger the retinal image.

Answer 25

Retinal image size.

Question 25

Monocular Vision: Name the definition: This term defines the effect of the atmosphere on how we perceive contrast conditions and colours of distant objects. When viewing objects through poor visibility such as haze or fog they appear to be at a greater distance than they actually are.

Answer 25

Atmospheric (or aerial) perspective

Question 26

Monocular Vision: Name the definition: As we look at objects at a greater distance the. texture and colour of the object reduces and they become less distinct.

Answer 26

Texture

Question 27

Monocular Vision: Name the definition: The relationship between an object or objects and the shadow by the sun is a strong cue. The position of the sun will increase or decrease the length of the shadows.

Answer 27

Highlights and shadows

Question 28

The period of dark adaptation for the rods is -

Answer 28

30 minutes

Question 29

Empty field myopia: Myopia means ___-sightedness and this case is caused by flight at ___ altitude or at ___, when there is nothing to look at. The eyes tend to adopt a resting focus at a point between ___ and ___ metres away, with the result that a distant object has to be fairly ___ in order to be seen, an obviously dangerous situation. This can be overcome by actively re-focusing the eyes on ____ objects such as the ground, clouds or stars.

Answer 29

Empty field myopia: Myopia means short-sightedness and this case is caused by flight at high altitude or at night, when there is nothing to look at. The eyes tend to adopt a resting focus at a point between one and two metres away, with the result that a distant object has to be fairly large in order to be seen, an obviously dangerous situation. This can be overcome by actively re-focusing the eyes on distant objects such as the ground, clouds or stars.

Question 30

Radial keratotomy surgery will result in -

Answer 30

the grounding of a pilot