Optic Nervous System

The human brain is capable of perceiving and interpreting information or stimuli received through the sense organs (i.e., eyes, ears, nose, mouth, and skin) (Weiten, 1998). This ability to perceive and interpret stimulus allows the human being to make meaningful sense of the world and environment around them. However, even as the human being is able to perceive and interpret stimuli information through all sense organs, stimuli is most often or primarily interpreted using the visual (eyes) and auditory (ears) sense organs (Anderson, 2009). However, for the purpose of this paper, the visual information process will be examined.

The brain is considered the most complex organ in the body. It is responsible for controlling motor function, the body’s ability to balance and the ability to translate information sent to the brain by sensory organs. The mind is described as the faculty of consciousness and thought. It’s where our feeling and emotions originate from and defines who we are as a person. The brain is composed of the visual cortex, which is responsible for processing visual information. In blind individuals the feature that makes up visions still exists in the visual cortex. These features are now used to process information received from the other senses. However, blind individuals are able to view the images because what’s in their mind.

Gibson’s and Gregory’s theories of perception both suggest that eye-retina is important for perception. The both believe that without eye-retina, a person will not be able to see. This is a common view of both of the theories of perception. The idea is supported by the case of SB. SB was a man who had been blind from birth due to cataracts. When he was 52, he had an operation which restored his sight and hence he could see. Thus, this case has shown the importance of eye-retina for things to be perceived. And therefore, supports both of theories of perception which eye-retina is essential for perception.

As vital organ of vision, the eye, allows us to learn more about the world around us more than any other organ or senses. Sight, the physical sensory experience and vision, the metaphysical concept of how our brain interprets images both work harmoniously and play a huge role in our everyday lives. However, almost a billion people are either blind or visually impaired simply due to not having a pair of glasses. Being able to lead people in the direction of good vision is what developed my interests.

When it comes to vision, we see things based on the light reflected from surfaces. The reflected light waves enter the eye through the cornea at the front of the eye, it's resized at the pupil, focused by the lens, and hits the retina at the back. The light is then detected by rods and cones, photoreceptors, which alters the light into electrical signals. The optic nerve transmits those vision signals to the lateral geniculate nucleus, where visual information is transmitted to the visual cortex of the brain then converts into the objects that we see.

The eye is the organ of sight. It is used in almost everything we do, from playing sport to reading. A normal and well functioning eye can focus objects and images, both near and far, perceive depth and adapt to changes in light.

Vision is the most important sensory compared to other sensory modality therefore there is a wide range of research carried out on vision. Visual attention is defined as a term that portrays how individuals are able to change their view while attending to an image that is of a normal perspective due to the neurones in the cortex (Carasco, 2011). It is often described as a focal point which is situated with different locations in the region of space (Wright, 1998). Visual search requires detecting a specific target as quickly as possible. For example, trying to find your car in a large car park. By focusing our attention to the specific environment it improves our visual search of the target (Keane et al., 2015). The speed of a visual search

Many people may know strabismus as crossed-eye, it is more commonly described as a disorder in which the eyes don’t look in the same direction at the same time. Strabismus is caused by defective nerves or muscles, or because of trauma. Looking at the muscle specifically, it affects the four rectus muscles which move the eyes up, down, to the right, and to the left, and two oblique muscles, helping the eyes look down and in or up and in. This disease affects the action of the eye muscles in doing their job properly, keeping it from controlling and

The optic nerve reaches from behind the eyes to the occipital lobe where this visual information can finally be interpreted into what we know as ‘seeing something’. It is at this point that it is useful as this is when colours can be perceived (Breedlove, 2010).

There are six extraocular muscles in the eye.  These control the movement of the eyeball.  The first muscle is the Superior Rectus muscle, this muscle is attached to the eye’s surface and causes it to move.  The muscle rotates the eyeball toward the midline and upward.  The second muscle is the Inferior Rectus muscle, this muscle helps move the eye downward.  This muscle can be found in the eye socket.  The third muscle is the Lateral Rectus muscle, this muscle is located on the lateral side of the eyeball.  Its responsible for the lateral movement of the eyeball.  The fourth muscle is the Medial Rectus muscle, this muscle is the biggest out of all the six of the eyes muscles.  This muscle is a muscle in the orbit, however its only function

     The brain is aware of its surroundings, via input from the spinal cord and cranial nerves. Cranial nerves with sensory functions allow us to smell and see. Nerves with both motor and sensory functions are responsible for everything from tasting and chewing, to breathing and the heating of your heart. Many of the little things we take for granted are also made possible by cranial nerves.

As defined by the American Academy of Ophthalmology (2) strabismus is a visual defect in which the eyes are misaligned and point in different directions. One eye may look straight ahead, whil e the other eye turns inward, outward, upward, or downward. You may always notice the misalignment, or it may come and go. A second disorder, amblyopia, commonly goes along with strabismus. Again, from the American Academy of Ophthalmology, Amblyopia is p oor vision in an eye that did not develop normal sight during early childhood. It is sometimes called lazy eye. (7) The reason these two conditions are so closely linked relates to how the brain interprets the information received from th e two separate eyes.

1) Describe the effects of the parasympathetic and sympathetic nervous systems on the smooth muscles of the eye