-
Looking for HSC notes and resources? Check out our Notes & Resources page
Visual Acuity? (1 Viewer)
- Thread starter Lukybear
- Start date
proletariat
Member
- Joined
- Nov 2, 2009
- Messages
- 134
- Gender
- Male
- HSC
- 2010
Visual acuity is caused by the number of individual signals sent to the brain.
Its not determined by the number of rods or cones-- its determined by the number of optic nerve fibres. e.g. Organism x has 130 million rods and cones but they are grouped by bipolar and ganglion cells and connected to 1 million nerve fibres. Organism y has 60 million rods and cones but they are connected to 2 million nerve fibres.
Since there are more individual signals sent to the brain in the case of organism y, it will have better visual acuity.
Humans have the fovea, which contains no rods or blood vessels. It only contains cones, and each cone connects to one nerve cell / fibre. This is where visual acuity is greatest in humans
And for your second question, blue cones absorb light between 380 nm and 520 nm, green cones detect light between 450 nm and 620 nm, red cones absorb light between 480nm and 680 nm. As you can see, red and green cones overlap between 480 and 620 nm. This means that a particular wavelenth may be seen differently as there are no red cones to contribute to the 'color'.
... and I think thats it. Also, if you are who I think you are, then this huge 30 minutes i spent that I could have been using to write a story was wasted XD
Its not determined by the number of rods or cones-- its determined by the number of optic nerve fibres. e.g. Organism x has 130 million rods and cones but they are grouped by bipolar and ganglion cells and connected to 1 million nerve fibres. Organism y has 60 million rods and cones but they are connected to 2 million nerve fibres.
Since there are more individual signals sent to the brain in the case of organism y, it will have better visual acuity.
Humans have the fovea, which contains no rods or blood vessels. It only contains cones, and each cone connects to one nerve cell / fibre. This is where visual acuity is greatest in humans
And for your second question, blue cones absorb light between 380 nm and 520 nm, green cones detect light between 450 nm and 620 nm, red cones absorb light between 480nm and 680 nm. As you can see, red and green cones overlap between 480 and 620 nm. This means that a particular wavelenth may be seen differently as there are no red cones to contribute to the 'color'.
... and I think thats it. Also, if you are who I think you are, then this huge 30 minutes i spent that I could have been using to write a story was wasted XD
Last edited: