L7: Vision Flashcards
What are the 4 types of neuron in the retina?
Bipolar, horizontal, amacrine & ganglion cells.
What is the Fovea?
Centre of the retina, makes reading possible.
What is the Lens?
A curved structure in the eye that bends light and focuses it for the retina to help you see images clearly.
What is accommodation in regards to the Lens?
When muscles adjust the curvature of the Lens to focus on near or far objects.
What is the Cornea?
The main lens of the eye, first point of contact for light information.
What is Hyperopia and how can it be corrected?
When the Lens is too weak or the cornea is particularly flat causing long-sighted vision, can be corrected with a converging lens.
What is Myopia and how can it be corrected?
When the lens is too strong or the cornea is particularly curved causing short-sighted vision, can be corrected with a diverging lens.
What is Presbyopia?
A refractive error that makes it hard for middle-aged and older adults to see things up close.
Behind the 4 types of Neurons, what are the 2 photoreceptors?
Cones and Rods.
What are rods and cones?
Rods: a photoreceptor that is Very sensitive to low luminescence, assists in night vision, none in the fovea and only has one colour receptor (Rhodopsin).
Cones: Very responsive to bright light, helps us to see fine detail, highly concentrated in the fovea and has 3 colour receptors (R, G, B).
What do bipolar neurons/cells do?
They connect the outer retina to the inner retina, they convey light signals from rods and cones to the retinal output.
What are the 2 categories of retinal ganglion cells/neurons?
Magnocellular (M-cells)
Parvocellular (P-cells)
What are the characteristics of an M-cell?
Sensitive to light not colour, get info mainly from rods.
What are the characteristics of an P-cell?
Smaller than M-cells, sensitive to colour, get info mainly from cones.
What is the blind spot?
A small area in the retina where blood vessels enter and exit the eye, has no photoreceptors.
