- Consider the conceptual physics behind the visual process. Explain how the curves of the cornea and the lens relate to the angle of light wave projection. Describe some of the changes or problems in the eye structure that can cause a problem with vision. Describe some of these problems and the way they alter or block light waves. For example, cataracts obstruct light waves, thereby causing problems with vision.
- Describe the role of photoreceptors and their location in the eye. Explain the importance of locations to other cells in the retina and the influence on light waves.
- The optic nerve produces a blind spot in our visual field. Explain how the knowledge about the blind spot and our lack of awareness teach us about the perceptual process.
Respond to at least two of your classmates.
Week 2 Discussion
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Kimberly Glover posted Feb 24, 2022 4:43 PM
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The cornea, the translucent front “window” of the eye, allows light to enter. The refractive strength of the cornea bends light rays so that they pass readily through the pupil. Cataracts are caused by the clouding of the eye’s lens. Glaucoma is a condition in which the fluid strain in the eye increases. Macular degeneration is a vision-threatening condition that affects the macula. Reflection is amongst the most essential wave-like characteristics of light. The light humans seen on our eyes is reflected light. The colors we see are also affected by how daylight reflects off objects. Farsightedness and nearsightedness are vision impairments that occur when a wave hits a new medium and some of the wave bounces off the surface. Nearsightedness Nearsighted people may see nearby items well, but distant objects appear hazy.
These photoreceptors are concentrated in the nucleus, which is the retina’s functional center and is located near the center of the retina. The fovea is placed in the macula’s center. The nucleus is responsible for color vision with great resolution, which is given by many types of photoreceptors. Image-forming cells are photoreceptors. They’re a sort of neuroblastoma cell that can absorb light and convert it to an electrical charge in the beginning stages of the vision function, a technique known as phototransduction.
There are also no photoreceptors in this tiny area where another nervous system passes through the retina’s surface. There is a blind spot if there are no photosensitive cells perceiving light. The eye cannot deliver any communications about the sight to the brain without photoreceptor cells, which normally translates the image for humans. There is a blind spot. The optic disk is where neurons with over one thousand retinal ganglion cells merge, marking the start of the optic nerve. The treatment and surveillance of conjunctivitis and other visual neuropathies that might cause vision loss could use a clinical examination of the eye lens.
References
Goldstein, E. B., & Brockmole, J. (2016). Sensation and Perception (10th Edition). Cengage Learning US.
https://digitalbookshelf.southuniversity.edu/books/9781305888326
Kathy Williams posted Feb 23, 2022 4:35 PM
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In most situations, we simply open our eyes, and see what is around us (Goldstein & Brockmole, 2016). There is physics behind the visual process, and there are ways that the cornea and the lens relate to the angel of light, wave projection. Problems and changes that could arise in the visual process, that can create major problems in eyesight (Goldstein & Brockmole, 2016).
Vision is based on light, which is the band of energy within the electromagnetic spectrum, and the eyes contain receptors for vison, and the light that is reflected from objects in the environment, enters the eye through the pupil, and is focused by the cornea and lens to form sharp images of objects on the retina (layer at the back of the eyeball), (Goldstein & Brockmole, 2016).The cornea and lens form a system that acts as one single thin lens, and to get a clear vision of something or someone, the image must be projected onto the light-sensitive retina (Goldstein & Brockmole, 2016). Visible light is the energy within the electromagnetic spectrum that humans can perceive, and has wavelengths ranging from 400-700 nanometers ( Goldstein & Brockmole, 2016). Light reflected from an object into the eye is focused on the retina by a two-element optical system: (1). The cornea, which is 80% of the eye’s focusing power, the transparent covering on the front of the eye, and cannot adjust its focus because it is fixed in place (Goldstein & Brockmole, 2016). (2). The Lens, supplies the remaining 20% of the eye’s focusing power, and can change its shape, to adjust the eyes focus for objects located at different differences (Goldstein & Brockmole, 2016).
Light waves enter the eye through the cornea, and the cornea refractive power bends in such a way that they pass freely through the pupil, (the opening in the center of the iris, through which light enters the eye),(
). As people get older, their ability to accommodation (adjustment of the optics of the eye, to keep objects in focus), decreases due to the hardening of the lens, and weakening of the ciliary muscles, which increases the focusing power of the lens, (Its ability to bend light), (Goldstein & Brockmole, 2016). In the near-sighted eye, parallel rays from a distant spot of light are brought to a focus in front of the retina (sensory membrane at the back of the eyeball), so distant object appear to be blurred (Goldstein & Brockmole, 2016).
There are certain things that can alter or block light wave such as UV lights, they can burn your skin and eyes without proper protection, and blue light, which can cause digital eye strain, which is called “Computer Vision Syndrome.” (
https://www.opticalmasters
In the visual process, photoreceptors are small cells located in the retina of the eye, that are vital to night vision, and also affects how the eyes see color, and there are two photoreceptor cells called cones and rods ((
https://www.allaboutvision.com
). These rods and cones convert the light into electrical impulses which are transmitted to the brain via nerve fibers (
https://chem.libretexts.org
).
The optic nerve produces a blind spot in our visual field. The optic nerve contains a million optic nerve fibers, that conduct signals towards the brain, and there are no receptors at the the place where the optic nerve leaves the eye, and this enables the receptors ganglion cell fibers to flow into the optic nerve, and this absence of receptors, creates the blind-spot (Goldstein & Brockmole, 2016). In this process, your retina has no light receptors (no rods or cones), for example, if I were to hold up a card, so the light from the dot fall from this spot, you cannot see the dot (
https://www.britannica.com
).
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https://www.britannica.com
)
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https://chem.libretexts.org
).
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https://www.allaboutvision.com
).
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https://www.opticalmasters
Goldstein, E. B., & Brockmole, J. (2016). Sensation and Perception (10th Edition). Cengage Learning US.
https://digitalbookshelf.southuniversity.edu/books/9781305888326
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