C06 - The Eye and Vision Flashcards
What does the Visual System contain (3)?
- The Eyes.
- The Optic Nerve.
- Visual Cortex.
What is the function of the Optic Nerve?
Connects the Eyes to the Visual Cortex.
What is the function of the Visual Cortex?
Responsible for processing information received from the Eyes.
True or False. 60% of all sensory information is processed by the brain is visual information?
False. 70%.
The outside of the Eye is covered in a smooth, very tough layer of white tissue called?
Sclera.
‘____’ allows light to enter the Eye and fall on the lens via a hole in the ‘____’ called the ‘____’ (3)?
- Cornea.
- Iris.
- Pupil.
What is the function of a Cornea?
Controls and focuses the amount of light entering onto the Retina.
What is an Iris and its function (2)?
- A structure surrounding the Pupil.
- Contracts and expands to light levels, thus altering the size of the Pupil.
Name two types of Photoreceptors and their functions (2)?
- Highly Light Sensitive Rods = Can’t detect colour.
- Less Sensitive Cones = Can detect colour.
Name two functions of the Cones?
- Responsible for detecting colour.
- Used for Daylight Vision.
What is the function of the Rods?
Used for Night Vision.
What is the Fovea?
Located in the central region of the Retina and is densely packed with Cones.
Define Vision?
The process of taking signals from the Eyes and interpreting them in the Brain.
Name four factors affecting Visual Acuity?
- Hypoxia.
- Smoking.
- Alcohol.
- Short/Long Sightedness.
Why do we have Blind Spots?
Because there are no Rods and Cones in the Optic Disc.
What is Empty Field Myopia?
When the Eye resumes a default focus of 1 or 2 metres, due to a featureless field of Vision.
How can we make objects more detectable at night?
By looking at them slightly off-centre.
What is the term and definition for Short Sightedness (2)?
- Myopia.
- The inability to focus on distant objects.
What is the term and definition for Long Sightedness (2)?
- Hyperopia/Hypermetropia.
- The inability to focus on near objects.
Define Astigmatism?
Reduce in optical power of the Cornea/Lens.
Define Presbyopia?
A form of Long Sightedness commonly developed with age.
Define Cataracts?
Clouding of the lenses.
Define Glaucoma?
A disease in which the internal pressure of the eye increases.
