10 Photopic Vision Flashcards
13 . What is Point Spread Function?
Distribution of photons during a shutter catch.
- What are the basic units of photopic vision?
Photons
- T/F: The visible light spectrum is narrow.
True
- What is the approximate range of the visible light spectrum?
390 to 700 nm
- Most of energy from the sun is in the _____ range.A) InfraredB) Visible LightC) Ultraviolet
C) Ultraviolet
- When looking at a star how many cones are defining most of the image, and where are they located?
3-4 cones.Center.
- What do the bumps in Point Spread Function indicate?
Optical aberration
- T/F: Cones align towards the nodal point
True
- What helps to guide the photons to the chromophore?
The inner segment guides the photon to the chromophore located in the outer segment.
- T/F: Directional sensitivity of cones increases photon catch
False, directional sensitivity of cones decreases photon catch.
- Out of the 5500 photons entering the eye, how many actually hit the chromophore?
~2900 photons
- T/F: L/M cone ratio is 2:1.
False, L/M cone ratios vary.
- The number of photons that reach the photoreceptors has an INVERSE or DIRECT relationship to their frequency?
Inverse.
- How long is the “shutter time” for cones?A) 5 msecB) 100 msecC) 500 msec
B) 100 msec
- Photon catch is integrated over a _____ time span.A) LongB) ShortC) Medium
B) Short
- Which photoreceptor (rod or cone) is very sensitive and can respond to a single photon?
Rod
Which photoreceptor (rod or cone) is very sensitive and can respond to a single photon?
Rod.
- Chromatic aberration can be described as a _______ on the retina.A) BlurB) RainbowC) Cloud
B) Rainbow
- Low frequency light (reds) focuses BEHIND or IN FRONT OF light?
Behind
- High frequency light (blue) focuses BEHIND or IN FRONT OF light?
In front of
- T/F: L cones are sensitive to short wavelengths?
False, L cones are sensitive to Long wavelengths.
- What is peak sensitivity to a cone?
Increased probability of a photon to be absorbed by a cone.
- T/F: L cones absorb 100% of all photons at different frequencies?
False, L cones absorb different frequencies of light at different percentages.
- At a frequency of 510 Hz, L cones respond to how many photons out of the 2900 that hit the retina?a.) 250b.) 170c.) 310
b.) 170
- What is the complex molecule that contains a chromophore and is found in the outer segment of a cone?
Rhodopsin
- T/F: Rhodopsin is a photon-catching molecule that contains chromophore.
False.
- T/F: Chromophore changes its shape from bent to straight when it absorbs a photon.
True
- Out of every 3 photons, how many end up hitting a chromophore?
2 photons
- T/F: Photoisomerzation is when a photon hits a chromophore isomer and changes it shape.
True
- T/F: If 700 photons cause photoisomerization of chromophore, only a fraction of photons are in the Point Spread Function.
True. Only 170 of photons are in point spread function
- ______ in the vitreous causes chromatic aberration secondary to difference in _______
Water, Index of refraction
- TRUE or FALSE:Brown circles contain ~25% of the photonsSmaller concentric circles contain ~ 50% of the photons
FALSEBrown circles contain ~50% of the photonsSmaller concentric circles contain ~ 25% of photons
- In the example from class, how many photons of a star’s light hit the retina?A) 58B) 684C) 1452
C) 1452
- Where is the image carried when the photons hit the cones? A) peripheryB) centerC) surrounding media
B) center
- Which of the following is out of focus?A) L cones B) M conesC) S cones
C) S cones
