How good is your eyesight?

Greetings, dear readers

The eyes, just like the feet, are a pair of body parts that are taken for granted more often than not. Until they stop working correctly, they are usually not appreciated for what they do. Possibly due to the lack of awareness regarding the eyeball in general, its function and the reason for its dysfunction. This ignorance could be altered by a basic understanding of the anatomy of the eye; a complex organ simplified by identifying its various physiological attributes.

Humans and animals alike require eyes to function in optimal condition. The eyeball exists to provide sight and, though they may vary in shape and colour, each one consists of similar traits such as the sclera, cornea, iris, pupil, lens, retina, macula, optic nerve and vitreous. The sclera, universally known as the white of the eye, is made up of fibrous tissue that gives it its shape and covers approximately eighty per cent of the organ itself. The cornea is a clear, dome-shaped structure that covers the front of the eye and transmits light into the eyeball, which is then regulated by its iris or coloured part. The amount of light rays allowed into the eye is further controlled by the pupil, which is the dark circle found at the centre of the eyeball’s visible surface.

eye_pic1316727402748
There’s more to the eye than meets the … eye? Hm. (1)

The transparent lens, positioned behind the pupil and part of the iris, changes shape in response to how far an image or object seems to the one looking at it. By doing so, it is able to focus light rays accordingly and ensure that they meet at a specific layer of nerves known as the retina. The retina covers the back of the eyeball and surrounds a set of specialised cells called the macula, which are particularly sensitive to light. The macula allows the eye to pick out finer details and, when functioning alongside the retina, aids the production and transmission of electrical impulses via the optic nerve, which connects the eyeball to the visual cortex of the brain. Last but not least, the interior of the eye is usually filled with a clear, gel-like substance called vitreous that helps the sclera keep its shape.

longsight1
What it says (2)

Disorders of the eye tend to occur when the aforementioned anatomical structures start to change, due to age or certain external factors, and dysfunction as a result. Though there are many different conditions that can affect the sight, hyperopia and myopia are among the most common. People suffering from hyperopia or long-sightedness tend to have cornea that are less curved than needed or have eyeballs that are shorter in length than usual. These physical changes can prevent light rays from focusing directly onto the retina and instead extend beyond the light-sensitive cells, causing images or objects that are closer to seem blurred or harder to focus on.

shortsight1
Can’t really get more simple than that (3)

Myopia or short-sightedness can be considered the opposite of hyperopia. Those with short-sightedness normally have no problem when looking at images or objects that are close but may find them blurred when at a distance. This can happen when the eyeball is too long or if the cornea or lens of the eye curves too much, causing light rays to focus in front of the retina rather than straight on it. Some disorders of the eye are caused by concentrating too often on close objects or images in childhood whilst others result from the vitreous slowly becoming water-like in consistency and therefore unable to keep the fibrous tissue of the sclera in the same shape, a natural process that happens during the passage of time.

We hope that this information has benefitted you, our dear readers, and we would love to hear from you. Comments, questions and weekly topic suggestions are always welcomed and greatly appreciated.

Thank you for reading!

The Pure Therapy Team

Images referenced from:
(1) https://classconnection.s3.amazonaws.com/698/flashcards/701698/jpg/eye_pic1316727402748.jpg
(2) http://www.rutherfordeyecare.com/wp-content/uploads/2010/07/longsight1.jpg
(3) http://www.rutherfordeyecare.com/wp-content/uploads/2010/07/shortsight1.jpg
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2 thoughts on “How good is your eyesight?

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