Eyes Overall Visual Performance

Please give a response to my classmates discussion post listed below. 

Describe what vision might be like if the retina had less convergence than it does, or perhaps none at all. What about if it had more convergence?

To understand what it would be like for the retina in our vision to have less convergence than it what it normally has, it is necessary to understand the role of the retina. The retina in our eyes, is in charge of transforming light into neural signals that are then processed by the brain. The retina contains two types of photoreceptors: the rods and the cones. There are a lot more rods than cones in each eye which according to “sensation and Perception” on Photoreceptors, “there are about 120 million rods in each eye, as opposed to only about 6 million cones” (UMGC, 2022). Rods are highly sensitive to light whereas cones dominate the photopic vision where there are occasions with high light exposure. There is a very important part of the eyes that concentrate on specific visual fields, the fovea. The fovea simply is, where our vision is focused on which is also where detail and color are processed. The duplicity theory states the fact that “humans have two main types of vision, which can basically be described as a vision for daytime and one for nighttime” (UMGC, 2022). The transitioning between photopic and scotopic vision is referred to as the mesopic vision which is when both rods and cones are active.

Therefore, if the retina had less convergence, our vision would be blurry as we tried to focus on close objects and our ability to process detail and color, will be a lot more difficult. Neural impulses can be initiated by the the retinal changing shapes due to being exposed to light which is also referred to as visual transduction. This is crucial for our vision as it converts the photoreceptors into electrical signals which explains why we tend to lose our dark adaptation when exposed to brightness. Without all of these components that allows our vision to transform light into signals that can be broken down by the brain, our ability to see in detail, would be compromised. the lack of convergence on one eye can impact the other eye’s ability to process light into information that can be processed by the brain which will, therefore, affect the way we visualize everything we see, whether that is from far distance or close distance. The lack of convergence can also affect the eyes overall visual performance creating blurry images on one eye and further ignoring such refractive error with the better-quality information from the other eye. On the other hand, if our eyes had more convergence, meaning, more cells are added to other cells which can result in higher sensitivity to light (UMGC, 2022). Rods are a lot more sensitive than cones which explain why cones are better in detail. Too much convergence may require treatment as one eye may be more sensitive to light than the other, although having one eye being more capable of seeing detail, is considered to be normal. 

References:

Sensation and Perception. (2022). Week 2 Learning Resources. Photoreceptors. Cellular Activity of The Retina. Retrieved from:

Week 2 Learning Resources – PSYC 310 6380 Sensation and Perception (2225) (umgc.edu)