![This gas permeable rigid contact lens does not contain water like soft contacts, is resistant to deposits, and is less likely to harbor bacteria. CREDIT: [PARAGON VISION SCIENCES, INC.]](http://scienceline.org/_s/files/2007/06/108288main_contact.jpg)
ask scienceline | health | biology
Why do people wear hard contact lenses?
- asks Lindsey from New York
Other than being generally awkward, I’ve spent most of my time since I was 13 getting things in my eye–or rather, getting things stuck onto my gas permeable, “hard” contact lenses. Other formative moments have had me blinking on command so friends and gathered revelers could see the tiny, glass-like chunk in my eye move and resettle.
About four weeks ago, when I was yet again ticking off the reasons why I was lucky enough to have thick lenses directly on my eyeball, it occurred to me that I had been reciting the same spiel–a strange eye shape, really really really bad eye sight–for more than a decade.
What if, the science had changed and I no longer needed hard lenses? What if I should have had years of soft contact wearing behind me, and I didn’t know it, because I was blithely tripping along following the advice of the eye doctor I had during my adolescence.
Turns out, he was a smart man (let the record show I never doubted him). For certain vision corrections, rigid gas permeable lenses provide clearer, more precise vision than soft lenses. This is mainly due to structural difference between soft and gas permeable lenses.
Since soft contacts are traditionally made with water, they can actually dry out, causing their shape to warp and preventing clear vision as well as becoming a potential irritant. To stay hydrated, soft lenses draw moisture from the eye, which can lead to dry eyes. Water also binds to tear proteins making contacts attractive to “pollutants,” such as lotions and soaps, which creates a chunky, gritty build-up on the contact.
Rigid lenses, being stiff, don’t change shape when the wearer blinks, so they stay precisely focused. Not only that, rigid lenses, unlike soft contacts, do not contain any water. Because they are made with silicone polymers, rigid lenses are more oxygen permeable, making them healthier for the eyes (though these days, some soft lenses, called “extended wear,” are made of silicone hydrogel–a substance that allows almost as much oxygen to flow through as rigid lenses, and is less water dependent ).
But this is not to say gas permeable lenses are problemless; they, too, have their downside. When you first get them, you can’t just pop them in right away. Rather, they are broken in by wearing them for increasing amounts of time as your eye adjusts to having a new lump of stuff in it (I believe my doctor told me my eyelid had to form a sort-of groove…). Even if you are lifetime wearer, leaving the lenses out for a few days means going through the process of again .
Also, rigid gas permeables must be scrubbed clean, and soaked, nightly–while soft contacts can be worn constantly, soaked or simply tossed. Hard contacts are more expensive too, as are cleaning solutions (up to eleven or twelve dollars a bottle). But if you don’t lose them or crack them, hard lenses last longer (that’s a big “if”).
So, it seems as though “hard” lenses–full of mystery, science, and silicone–still serve an important function for certain contact wearers. Some last interesting facts about contact lenses:
1. Rigid gas permeable lenses are not the “hard” lenses of yesteryear, which were actually made of an oxygen-impervious substance called polymethyl methacrylate–truly “chunks in the eye.”
2. Gas permeables can also be used for nifty technique called orthokeratology, in which the lenses are worn–usually overnight–to reshape the cornea, leaving the patient with 20/20 vision. The effects of this last only one or two days, however, which is probably why it hasn’t caught on with all contact wearers.
*An interesting side-note: if you are wanting the best of both worlds, there is a new contact out with a rigid center, and soft circumference. Check it out…
June 25th, 2007 at 5:57 pm
I wore hard contacts my whole life, too, until last spring. The doctor suggested I just give some soft ones a try, because they would correct my vision “almost” as well as gas permeables. Turns out I couldn’t even tell the difference (I mean, I guess my right eye is SLIGHTLY blurry but with both eyes open I don’t notice at all) and I find them much more comfortable than my old ones. I’m converted! I have to say, though, I miss being able to amaze people with the whole blink-and-watch-it-go novelty act, and I also miss having the option to moisten/clean a contact in my mouth when necessary. …Probably not doctor recommended, but don’t even try to pretend you haven’t done it!
June 27th, 2007 at 5:28 pm
GP’s (gas perms) can be made more comfortable if they are made larger. Today’s computer controlled lathes can make better fitting gas perms and larger ones that can tuck under the lids. Lid interaction is what most GP wearers notice. Perhaps it’s too late for most people since soft lenses have already taken over the vast majority of eye doctor’s lens fits.
The Synergeyes lens is one very nice option.
August 17th, 2007 at 8:49 pm
I’m glad I’m not the only one who will be wearing the hard lenses still, I insisted upon getting them because I found the soft ones to be awkward and blurry for me. Even so, getting used to them is a real pain.
September 20th, 2007 at 2:36 am
Well at the age of 55 I was a little fed up with reading glasses and having different strength ones for working on the computer, which is my job, so I now have zwave multifocal RPG lenses. This is my third week, and I really find things blurry WITHOUT my lenses. But my eyes were very, very, tired before I asked for lenses as they were struggling to focus. RGP’s were recommended for their clarity and longevity and so far I’m convinced. But technology is still moving forward and who knows what new things will hit the market in the next few years.
Three weeks is about the norm for getting used to these I’m told, and it seems I’m fairly normal in that.
August 7th, 2008 at 1:37 pm
I wore hard lenses from 1977 to 1994. When I moved and changed eye doctors, the new guy prescribed gas permeable lenses. I found them to be even more uncomfortable than hard lenses, and they didn’t give me the clarity of vision I got from hard lenses. Gas permeable lenses also seemed to be lighter, and didn’t rotate quite as well as hard lenses. They required more intensive cleaning, and picked up way too much protein deposits. When I complained about all this my new optometrist switched me to soft toric lenses, which were comfortable, but didn’t give me near enough clarity of vision. Both gas permeable and soft lenses made my presbyopia bad enough that I had to wear reading glasses to read.
By chance I had saved a very slightly used pair of hard lenses from my original prescription in 1977. I put them in just for fun, and they work so much better than any of the newer type of lenses. I no longer need reading glasses, and I can see distance wise just as well or better than gas permeables.
I have an eye exam next week, and I’m going to demand that the optometrist issue me hard lenses in a duplicate prescription, or I’m going to change doctor’s until I find one that will. I should have never allowed this guy to talk me into going gas permeable in the first place. Sometimes the so called new technology is not the best for everyone.