Week 9 - Vision and Visual Perception Flashcards
What is Diplopia?
Double vision
What is visual acuity?
A measure of the ability of the eye to distinguish shapes and details of objects at a given distance
What is visual convergence?
The ability of the eyes to to move inward to focus on an object and back out to the centre
What is hemianopia?
When you loose sight in half of your visual field in one or both eyes
What is visual extinction?
When the ability to perceive multiple stimuli of the same type at the same time is impaired. For example, if all items are put on the affected side, the person can attend to it. However if items are spread across the affected AND non-affected side, the person will only be able to attend to the non-affected side.
When is a referral to an ophthalmologist appropriate?
- Formal Ax of hemianopia
- Ax of eye health
What is the difference between an Ophthalmologist and optometrist?
An ophthalmologist is a medically trained doctor that specialises in eyes.
An optometrist fits people for glasses
When is a referral to an optometrist
appropriate?
- Visual therapy
- Ax of oculomotor, visual process and perceptual disorders
- Alternate eye patching (for disorders like diplopia)
- Prism glasses (for disorders like hemianopia)
What is Agnosia?
An inability to recognise or make sense of incoming sensory information even through sensory capacities are intact. They are relatively rare and can affect any modality (vision, auditory, touch etc)
What are the four types of agnosia?
- Visual object agnosia
- Prosopagnosia
- Colour agnosia
- Simultanagnosia
Describe visual object agnosia
The inability to recognise objects using vision although visual system is intact
- Rare and usually occurs with another agnosia
- Lesion sites include the right parietal lobe and inferotemporal cortex
Describe prosopagnosia
The inability to recognise faces although sensory abilities are intact
- Often occurs with visual object agnosia
- Lesion sites include the occipital-temporal junction, right occipital lobe or anterior infereotemporal cortex
Describe prosopagnosia
The inability to recognise faces although sensory abilities are intact
- Often occurs with visual object agnosia
- Lesion sites include the occipital-temporal junction, right occipital lobe or anterior infereotemporal cortex
Describe colour agnosia
The inability to associate common objects with colours, but can match colours
- Lesion sites include angular gyrus
Achromatopsia is a type of colour agnosia in which all colours appear less bright and it is difficult to match or sort colours of shades of colour.
- Lesion site includes the inferiormesial occipitotemporal cortex
Describe simultanagnosia
Difficulty recognising the meaning off a total array of pictures
- Lesion site includes bilateral or left occipital or diverse areas
