The first theoretical pair of contact lenses was described by Leonardo da Vinci in his Code on the Eye, no surprise there. The first practical pair was developed in 1877 by a Swiss doctor named A. E. Fick. (I love the names of these people, really. Like the safety razor guy.)

The early lenses were glass and were blown or molded into the appropriate curve. They also covered not merely the cornea, but THE ENTIRE EYE. Can you imagine what they must have felt like? It's no surprise that glasses still remained the more practical method of vision correction until 1936 when a plexiglas lens was introduced, and then in the 1940s a cornea-only lens was developed. Which doesn't change the fact that I can't wear them because of weird allergies.

contact lenses can be quite handy as well as necessary. Handy when wearing a helmet driving a motor cycle, necessary if you have myopia and still want to play rugby. Quite uncomfortable if you're drunk and want to go to bed (and have the lenses yo do need to remove before sleeping) or staring to the computer screen for too many hours. Aka, pros and cons. Therefore I wanted to be well-informed before purchasing them.

There are two types of contact lenses: hard and soft ones.
Hard lenses are more durable than soft contact lenses and, when taken good care of, last up to five years (in that case cheaper than soft lenses). They're considered as healthier for your eyes because they are oxygen permeable ("rigid gas-permable lenses") and are more often cleansed, which prevents eye infection. The lenses are made from plastic polymers like cellulose acetate butyrate, polyacrylate-silicone or silicone elastomers. Hard lenses must be carved to fit and will slip if not correctly formed. This is often considered as a (initial?) major drawback of starting to wear hard lenses.
Soft lenses are less durable, depending on the type you buy: sports lenses, one-day, one-month or about two years. They are made from hydrogel polymers; combined with the water of the eyes carrying the required oxygen. However, this system provides less cleansing (especially getting rid of those sticky proteins is important), hence there's a greater chanche of eye infections like Keratitis (inflammation of the cornea by Pseudomonas and Acanthamoeba strains). On the other hand, they easily take the shape of your eyeball, adding up to convenience.

Some statistics: in 1998 there were appoximately 270312000 US citizens (according to my atlas), 34 million people wearing contact lenses and fewer than 15% of the contact lens wearers use hard lenses. One of the myopia write-ups says that about 50% of the population does use either type of eye-correction. 34 million of that equals about 25% of of the total group of "visually impaired" people; or 75% is still wearing glasses, whatever way you want to put it.

For you people who want to know: I've had soft contact lenses for 2 years, but because of the prize difference I went back to wearing glasses, and I'm used to them again. Other advantages are that I've the option to change my look every couple of years and I'm taken more seriously...

Information from the optician and the article "Working Knowledge" from the Scientific American, October 2000.

How to Put in Contact Lenses

If you're like millions of other near- and farsighted people in the world, you probably are considering buying contact lenses, if you haven't already. While the benefit of improved vision without glasses usually persuades people to join the happy masses and immigrate to contacts, others are intimidated with the idea of jabbing plastic circles in their eyes. Indeed, putting in contacts is a great tribulation for new users (I spent about half-an-hour jabbing them in my eye with the aid of family members my first day). The following are two different methods for getting these little discs of wonder into your eyes. The first is recommended by most optometrists while the second is the method favored by myself and my parents.

Place-in-Center Method

The "Place-in-Center Method" was taught to me by my optometrist the day I got my contacts. The steps are as follows (I'm a rightie so if you're a lefty you'll have to switch directions for everything):

  1. Place the contact lens on your right index finger. It should be upright, standing concavely away from your finger.
  2. Using the middle finger of your right hand, pull down your lower eyelid.
  3. Using the opposing hand's (i.e. the left one) index finger, pull up on the upper eyelid.
  4. Now comes the tricky part: place the contact gently on the pupil of your eye using your pointer finger. Make sure to keep your eyelids open with your two other fingers!
The major drawback of this method is that, because you're placing an object directly on the pupil, you're eye will try to blink and you'll probably go crazy jabbing the lens into your blinking eye.

The Sclera Method

"The Sclera Method" is named after the whites of your eyes. This much simpler method is carried out in the following way (again, this is for a rightie):

  1. Place the lens on your finger the same way you did for the "Place-in-Center Method."
  2. Again, pull down the lower lid using your index finger.
  3. Here's where things can get a little dicey: place the contact lens on the white part of the eye revealed when the lower lid was pulled down.
  4. Now, move the inserted lens on top of the iris using your pointer finger. You may have some air bubbles trapped underneath the lens; moving it up should release any.
This method is my preferred choice because it reduces the possibility of blinking the lens out while trying to put it in. When the lens is placed on the sclera it isn't "picked up" by the retina and therefore doesn't cause the blinking reflex. However, you have to deal with air bubbles getting trapped under the lens and, if moving something around in your eye seems gross to you, the first method might be preferable. In either case, have fun with your new 20/20 vision!

Determining Whether A Soft Contact Lens is Inside Out

Due to the flexible nature of soft contact lenses, it is possible to invert them and put them in your eyes inside out. While this generally does not cause damage to the eye, it usually reduces the effectiveness of the contact lens and causes the lens to be very uncomfortable while in your eye. Therefore, before inserting soft contact lenses, it is important to be sure that they are turned the correct way.

In general, there are three methods to determine whether a lens is inside out or not.

The Wetting Method

Place the contact lens in the palm of your hand and allow it to air dry for several seconds. Then carefully place one or two drops of contact lens solution in the middle of each lens. If the lens is correctly inverted, the edges of the lens should fold inward.

The Taco Method

Allow the lens to air dry for several seconds after being placed on a fingertip. With your other hand, pinch the edges of the contact lens inwards. A correctly oriented lens's edges will bend inwards, like a taco. The edges of an inside-out lens will resist folding.

The Inspection Method

Place the lens on the end of a fingertip and hold it up so that you are looking at it directly from the side. Observe how the edges bend. An inside-out lens's edges will flare out slightly, whereas the edges of a correctly inverted lens will point straight upwards, like a bowl. Supposedly, the edges of an inside out lens will also look sharper, but I've never been able to see enough difference between states to notice this.

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