With regard to central vision, which of the following statements are correct?
1. It is due to the functioning of the rods
2. It enables details, colours, and movement to be seen
3. It is very active both during the day and at night
4. It represents the zone where the highest density of cones is found
CENTRAL VISION
Central vision is the most important part of a person's vision. It is used to read, drive, and see pictures or faces. Good central vision allows a person to see shapes, colours (thanks to the presence of cones), and details clearly and sharply.
Central vision is vision at the Fovea. The Fovea is the part of the retina which is composed only of cones and it is the most central part of the retina. It is the area of highest visual acuity and away from the fovea the acuity declines rapidly.
The cones are used for direct vision in good light and are colour sensitive.
- As stated above, it is due to the functioning cones (not rods). Rods are responsible for our peripheral vision - not central vision.
- As light decreases, the sensing task is passed over from the cones to the rods. This means that, at night time, with a dimly lit flight deck, the colour of instruments must be bright enough for cone vision to be used.
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