The Visual System



The body is made up of lots of systems working together to get us up and functioning as a normal human being. Whenever any of these systems become faulty or does not perform is function as expected bad things happen, pathologies occur, disabilities occur and people tend to ave difficulties with living. The visual system is not exception to this and today we would be looking at what goes into the operation of the visual system, basically how we are able to see the thing we see.


The visual system as already mentioned is the system in the body responsible for sight and involved more than just the eyes as most people tend to limit it to. It starts from the eyes and goes all the way back to the brain to the occipital lobe parts called V1, V2 and V3. So the visual system comprises the eyes, lids, lashes, lacrimal apparatus (tear system), bony orbit and its contents, extraocular muscles, blood vessels, nerves and the brain. The organ eye focuses light unto the retina and transduce it into electrical impulses to be sent to the brain for interpretation, the lids protects the eyes from mechanical injury and foreign bodies, the lashes protect the eyes by directing sweats from the eyes, the lacrimal system lubricates the eye and also contribute a small quota to the refraction of light, the bony orbit houses the eyeball and also provide mechanical support and protection, extraocular muscles enables movement of the eyes, the blood vessels provide nourishment to the eye, the nerves provide innervation to the various aspects of the eye and the brain does the final interpretation of the impulses it receives.


Functions of the Visual System
The visual system allows us to see and see distinctly, it enables us to see color and also differentiate between different colors (people who have a defect with this are known to be color blind), it allows us to tell objects apart from their background, enables us to perceive depth and also we are able to judge or estimate distances by help of the visual system. The functions are not exhausted though however these are some few that one may easily relate to.


The Process Involved in Image Formation
Light from an object or the environment is refracted by the help of the cornea through the pupil and further refracted by the lens through the vitreous humor unto the retina. The pupil constrict in the presence of excess light to prevent damage to the retina and dilates when light is hardly available to enable more light to enter the eye. The lens also adjust its shape and power accordingly depending on the proximity of the object to enable refining of the refraction process a process known as accommodation. When the light falls on the retina it converted to electrical impulses in the process known as transduction this is done with the help of retinol or otherwise known as vitamin A which is why vitamin is very important to the eye and vision, it contributes a lot to we seeing and seeing well, its deficiency results in a condition known as night blindness. From the retina the impulses are sent via the optic nerve (CN2) through the optic tract, then the radiations within the brain to the occipital lobe where the interpretation is made. At the junction where the impulses enter the optic tract some goes to the midbrain to control pupillary constriction and sleeping pattern, so also goes to the frontal lobe of the brain to an area known as area eight (8) which has a function in ocular fields and movement.So basically we see with our brain, meaning you can have good eyes and still not see


Light and Dark Adaptation
This a physiological process that involves the eyes, dark adaptation occurs when one enter a dark environment from a light environment, the eyes has to adjust the process of image from been in light to entering a dark environment and so for a while one may not be able to see things clearly however after about 15 minutes everything become clear although not colored, things appear grey-white. When this happens know and understand that it is physiological process and that you are not going blind in darkness. Light adaption is the vice versa however it takes some few minutes if not seconds to adjust, this is because the process involved in seeing in light is faster and has more cells differentiated for that particular function.


Your eye is comparable to a camera, it takes in the light and forms and image, any obstruction to any of the various processes involved in its function can result in significant impairment. It is a delicate instrument and more precious and expensive that your camera and so you have got to take care of it as such. Your health is your wealth, your vision is our priority. Live a good life.



What is @bettervision about?

@bettervision is is a project initiated by @nattybongo and friends to give back to the society the knowledge and skill acquired through the Optometric Studies in Kwame Nkrumah University of Science and Technology, Ghana.It is an outreach system where we visit the less privileged communities to offer free eye screening services and education to the people within the community

To reduce or prevent vision loss through diseases such as glaucoma, cataract and refractive errors.

To enlighten the majority of the Ghanaian population about the importance of proper visual care.

To conscientize people on the need for regular eye checks

To get more people to have their wards screened within the Critical periods of a Child’s Vision Development; thus from ages 3 to till about 10 years.

To help the blind and people with low vision live a better life within the society through education of the general public to stop stigmatization.

To help in the fight of extreme poverty that puts the health of people at risk


Our greatest gratitude goes to @fundition @adollaraday @surfyogi @girlsfoundation @bleepcoin @ackza @indigoocean @nanzo-scoop @steemstem @demotruk @pennsif @steem-ambassador @kasho and @wafrica for helping to make the aims and objectives of @bettervision a reality.

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