They reflect your state of mind and emotions, they work tirelessly all day long and are a masterpiece of nature. But how do eyes actually function? And what is the meaning of common abnormalities such as myopia, farsightedness and astigmatism?

An ingenious camera

When converting light into images, all parts of the eye perform their own task. The front part of the eyeball or cornea collects and focuses the light. Behind the cornea is the iris, which determines the color of your eyes. Small muscles in the iris ensure that the pupil, the small opening in the center of the iris, becomes smaller or larger. In bright light the pupil shrinks, in the dark it becomes larger. The lens is located directly behind the pupil. The lens can change strength by becoming more convex or flatter. This allows us to see clearly both up close and far away. The refractive power of the lens is expressed in diopters. Ultimately, the light reaches the retina. This contains cells that convert light stimuli into electrical stimuli. These stimuli are sent via the optic nerve to the brain and converted into images.

Eye abnormalities

Nearsightedness or myopia

People who are nearsighted see distant objects blurred. This is because the eyeball is too long in relation to the combining force of the cornea and lens. The light from distant objects is therefore focused in front of the retina instead of on it. Myopia is corrected using spectacle lenses or lenses with a negative diopter power. In this way the image shifts backwards. If you have myopia, don’t be alarmed that those distant objects don’t actually have to be that far away. There are many people with this eye defect who can no longer work with a computer without lenses or glasses. After all, the screen is already too far away from the eye. Only reading books is still possible without any problems, the rest needs correction.

Farsightedness or hyperopia

Farsightedness occurs when a person cannot clearly see nearby objects. The eyeball is too short, causing the light rays to converge behind the retina. Glasses or glasses with positive power are used for the correction. The bundling of the light is thus moved forward to the retina. This is primarily an eye defect that occurs in many people as they get older. Reading the newspaper or a magazine no longer goes so well and you have to keep the text a little further away from you. Then it will be easier to read again. However, this is not the correct method to correct farsightedness. It is always best to consult an ophthalmologist.

Astigmatism

Astigmatism occurs when the cornea has an irregular curvature. The incident light rays are therefore refracted asymmetrically. Anyone with astigmatic may perceive objects, both near and far, as slightly ‘distorted’. Glasses with toric or cylindrical lenses compensate for these distortions.

Cataract

With cataracts or cataracts, a clouding of the lens of the eye occurs. This can go on until the lens becomes completely opaque and you can no longer see anything clearly. This abnormality occurs in many people from the age of fifty, but few people suffer from it. They hardly notice it or hardly notice it. It is only at an advanced age that the cataract is experienced as very disturbing. People with diabetes are at a higher risk of this eye disorder.