English Version

The eye contains various things, one of which is the lens which we will be talking about today.

Let’s play a little game, put your finger in front of your face and focus on it, what happened to the background? It blurred. Now I want you to switch, focus on the background, now your finger is blurred, and that’s what we call eye accommodation. Our eyes work just like the camera. It can focus at one distance at a time, but how does this work? 

 In order for us to see, the object we are looking at needs to reflect light on the eye in order for it to hit the fovea, which is a part of the retina, and this is usually performed by the cornea which always reflects the light by the same amount, but why does it blur when I focus on something? Our lens is connected by the suspensory muscle and the ciliary muscle which controls the shape of the lens, so when we focus on a near object the ciliary muscles contract inwards towards the lens so the suspensory ligaments slacken (become loose) so it’s no longer pulling tight on the lens which leads the lens to return to its thicker shape so it can reflect the light more strongly to see near object. On the contrary, when we focus on a distant object, the light doesn’t need to be reflected strongly, so the ciliary muscle relaxes moving away from the lens and pulling the ligaments towards it which stretches out the lens, so it can see the distant object. But if the eye accommodation doesn’t work right it results in two cases: the first case is long-sightedness which means the lens can’t refract enough light so they are unable to focus on nearby objects but can see distant objects clearly. The second case is short-sightedness which means they refract too much so they can’t focus on distant objects but can see near objects just fine.

 To wrap it all up, Accommodation is a reflex that changes the reflective power of the lens to see near objects and distant objects, so when we want to see a near object your lens needs to be in its thicker shape, and when we need to see a distant object our lens needs to be stretched out. So next time when you need to focus on more than one thing, remember your lens can focus on one distance at a time.