Why you need Glasses
The eye is like a camera. The cornea and lens are lenses in the front of the eye that focus light sharply at the back (retina). If your eye is too long or short, your cornea and lens do not focus images on the retina and you need glasses or contact lenses to sharply focus the images you are looking at on the retina.
There are 5 main focus errors of the eye:
HYPEROPIA OR FAR SIGHTEDNESSIf you struggle to see nearby and distant objects then you are probably “far sighted” (also known as hyperopia). When you are younger the lens in your eye is able to adjust for hyperopia. But as you get older, your lens becomes less flexible, you have difficulty adjusting the focus and your eyes get tired so you start needing glasses to read. Later you become even more frustrated when you need glasses to see in the distance too. Your plus (+) glasses get thicker and heavier on your nose (and more expensive!). When wearing glasses your eyes will look bigger through them and everything you look at will also look bigger than when you are wearing contact lenses.
MYOPIA OR SHORT SIGHTEDNESSIf you can see well nearby but can't see objects further away, you are “short sighted” (also known as myopia). Children start to struggle to see the blackboard and do sports. When wearing your minus (-) glasses your eyes look smaller through them and everything you look at will also look smaller than when you are wearing contact lenses.
ASTIGMATISM OR RUGBY BALL SHAPED EYES
You don’t really have eyes which look like rugby balls but there are differing curvatures on the cornea (or clear window at the front of the eye). Almost everyone has some astigmatism and it often occurs with myopia or hyperopia. But significant astigmatism causes more blurred vision for near and distant objects. Glasses with astigmatism correction have to be “spot on” and a new pair of glasses can be difficult to get used to. Correcting astigmatism with contact lenses can be difficult because the lenses change position as you blink, changing your focus with each blink.
PRESBYOPIA OR READING DIFFICULTIES FROM ABOUT 45 YEARS OF AGE
You have presbyopia. The lens inside our eyes is getting older and is no longer able to adjust from distance to near focus. This happens to all of us unfortunately. If you have never worn glasses (emmetropia), you become very frustrated at having to wear glasses to see nearby for the first time. If you are also hyperopic (far sighted), you will start having difficulties and need glasses for reading when you are younger and by your mid forties you will need glasses to see in the distance (driving) and to see near objects (reading). And if you are myopic (short sighted) and presbyopic, you will find that with your contact lenses in you need reading glasses in addition to the lenses. And when wearing your glasses you may start taking them off to read.
Keratoconus is a condition of weakness of the cornea. It causes changing astigmatism which gets progressively worse, especially in your teens or twenties, or during pregnancy. The astigmatism may become difficult to correct with glasses and a hard contact lens may become necessary. And you may need frequent changes to your glasses or contact lenses. Corneal cross linking strengthens the cornea and stops the condition from getting worse.
YOUR VISION MAY BE CORRECTED WITH:
- Laser eye surgery (LASIK, LASEK and PRK) which reshapes the cornea, changing its focus.
- Replacing the lens in your eye (known as a refractive lens exchange).
- Placing an additional lens between the cornea and your natural lens like wearing a permanent contact lens in the eye (known as an ICL or intraocular collamer lens).