The type of contact lenses
I currently use. Short for rigid gas permeable contact lenses
, these are made of (I think) clear polymers
. They are generally smaller than the regular disposable
Although the initial discomfort turns many away from this option, there are many advantages to this type of lens. Basically, it is health and well-being over convenience (I choose well-being thank you).
The soft type of lenses, not known to many people, literally choke the eye. The material that makes those lenses are not very gas permeable, and extended usage (over 12 hours) is harmful to the eyeball.
The result of overuse? Pretty disgusting. It comes in the form of tissue growth on the inside edge of the eyelids. Slowly, it grows, until your eye is all fucked up. Ewww. Not a good thing to think about.
Just a sidenote, I know people who wear the same lenses for half a year at a time. Isn't that just plain stupidity? Think of all the protein buildup and lack of oxygen for the eye, not to mention that the natural tears are less effective at dealing with the removal of bacteria on contact lenses. God knows what will happen to your eye after 10 years of that. Infections, swollen eyelids, eye damage, etc.
The hard type of lenses permit very free gas exchange between the outside and the inside surfaces of the lens. Which means you can wear it for 12 hours and it is fine.
Due to genetic disposition, by the time I was 3 I had severe myopism and astigmatism. Soft lenses don't fix astigmatism. Hard lenses do. It rocks.
These lenses are less comfortable at first, but they are healthier in the long run and feel fine after 6 months.