To truly understand the issues that affect your eye health, it’s best to start by knowing about the different parts of the eye and what they do. But that can feel overwhelming: even if you’re comfortable with medical jargon, the fact remains that the eye is incredibly complex. It’s made up of many parts, often with confusing names, all performing incredibly sophisticated functions.
If your eye doctor has advised, for example, that you have something wrong with your retina, it helps to have some context for what that means. So in this post, we’ll present some basic facts about the retina – which comprises the largest part of the eye but is actually part of the central nervous system (just to make things more complicated).
It’s often said the eye works like a camera, but no camera can compare to the wonder of the human eye – and the retina is at the centre of the action. The outer part of the eye is like a lens that takes in external stimuli (in the form of light) and sends it to the retina (the ‘film’) to be processed and sent up the optic nerve to the brain, which translates the light into the images that form our vision.
To give a little more detail, the iris controls the amount of light that gets sent through to the retina, which is made up of light-sensitive neurons. These are called photoreceptor cells, and there are three types: rods (which provide black-and-white vision and help us see in dim light), cones (which support with the perception of colour), and ganglion cells (which help us react to bright light). The macula forms the centre part and thus is responsible for our central vision, while the rods and cones outside the macula provide peripheral vision. The central part of the macula is called the fovea, and it has an extremely high concentration of cones. This means your vision is at its best (ie, images are clearest) when you are looking directly at something.
Signals from the rods and cones are processed and sent along a neural pathway called the optic nerve that feeds the information to the vision centres in our brains – hence the retina being considered part of the central nervous system. To do this, the retina has to compress the data to fit the capacity of the optic nerve in a complex process called spatial encoding. And of course, all of it happens at lightning speed.
Because of its vital role, a healthy retina is essential for normal vision, and any disorder, damage, or disease of the retina will have a significant impact on our sight. Conditions that could affect the retina include age-related macular degeneration, diabetic retinopathy, colour blindness and retinal detachment (in which the retina separates from the back side of the eye).
A test to check the health of your retinas (called an ophthalmoscopy or sometimes a fundoscopy) is often given as part of a standard eye exam. The interior of the eye can be viewed through the pupil and because the doctor will need strong light to look into the back of your eyes, eye drops are administered that keep the pupils dilated. You may need someone to drive you home after the test, as it can blur your vision for several hours. If you have any questions or concerns, be sure to ask your ophthalmologist or eye care team who can help you determine whether you should have an ophthalmoscopy. Get more information about retinal detachment here: https://www.moorfields.ae/dubai/retinal-detachment/