Eye-sight conditions

The 4 main eye-sight conditions are myopia (short-sightedness), hypermetropia (long-sightedness), astigmatism and presbyopia.

Myopia

When it comes to myopia, size actually is everything.  If you are short-sighted your eyeballs are too big, or too long.  A clear image is formed somewhere in the middle of the eye, not on the retina, at the back.  Lenses are needed to push the image back to the retina.

Hypermetropia

If you are long-sighted, your eyeballs are too short.  A clear image forms somewhere behind your retina (in your brain perhaps) and lenses are needed to pull the image forwards, to the retina.

Astigmatism

The clear front surface of the eye (cornea) should be like the surface of a squash ball – equally curved whichever way you look at it.  However, if you held a squash ball between your thumb and index finger and squeezed gently, the surface of the squash ball would now have astigmatism.

Presbyopia

Literally, presbyopia means “old eyeball”.  The autofocus lens inside your eye is becoming harder and less flexible year by year, affecting your ability to see close up.  This results in the need for reading glasses, bifocals or progressive glasses.  Most of us are affected by presbyopia in our mid to late 40’s.