Short Sight & Retinal Detachment

Why are Short Sighted people more prone to retinal detachment than Long Sighted people?

A short sighted eye, is an eye that didn’t stop growing when it was supposed to (around the age of 8 years old). The retina is the light sensitive film that hugs against the back of the eye. Light hits the retina, and the light signal is converted into signals that are sent along the optic nerve to the brain. That’s how we see.

The retina is extremely thin and fragile – think about that thin wispy film that’s in onions! The retina rests between the very back of the eye, and the vitreous – the fluid within the eye, and is attached firmly at certain points of the back of the eye. As I said, a short sighted eye kept growing – so it’s a slightly larger eye than a long sighted eye. The size difference is very small of course, but, in a short sighted eye the retina rests a bit more precariously across the back of the eye – because the eye is bigger!

So, the retina is the same size, but is stretched across a bigger area – this makes it vulnerable. The retina had NO pain receptors, so anytime it’s aggravated, whether due to a tear, or it comes away from the back of the eye, or it’s tugged at by the vitreous, we don’t feel any pain. What the retina DOES have is photoreceptors, which are receptors that only respond to light. So yes, this means that when anything happens to retina, (like that aggravation described above) we see light, but feel no pain. This is what we mean by flashes. Flashes, if they happen at all, are usually seen out of the corner of your eye, and kind of look like… well… flashing lights! If you see flashes, something is happening to the retina.

So that’s why short sighted people are more prone to retinal detachments – literally because a short sighted eye is bigger than a long sighted eye. If you are very short sighted (minus 6 or higher) – you may want to think twice before going bungee jumping! 

 Another Great explanation provided thanks to Sandra Brady (FAOI), The Eye Centre opticians, Cavan.