why testing of contact lenses is done in rabbits?
405551
One of the problems with contact lenses is that they can interfere with the oxygen the eye's lens receives from the air (no blood vessels in the lens).  Rabbits have been used for many years to test the effects of new products for irritation in case they get into the human eye.  Humans would have to provide knowledgeale consent to allow chemical eye test (or to check new contact lenses).  Rabbits perform the task without consent, right?
239586
Go to your eye doctor and get tested.
354471
Some surgeons will, but the more respectable ones won't.  The reason is because it is very hard to monitor your glaucoma after LASIK because the intraocular pressure readings will not be accurate, so it will be difficult to determine how well your glaucoma drops are working.
458441
My guess would be that no, you could not evaluate the efficicacy of antidepressants in animals.  This is because depression isn't something you can measure objectively and there are no lab tests you can do to see if someone (animal or human) is depressed.  Depression is more subjective or experiential, and diagnosing it relies on the patient's narrative.  Since you can't ask a rabbit how they're feeling today compared to yesterday, or if they have hope for the future, you're not going to be able to see if the drugs were effective.\n\nHowever, you probably could look at side effects alone.  You wouldn't know if it was working against the depression, but you would know if it caused any serious side effects.  But I don't like the idea of testing on animals (inhumane).
405888
Corneal neovascularization has a low incidence among contact lens wearers who properly care for their lenses, follow all cleaning directions, and discard their lenses at the appropriate times. Typically patients who use extended-wear lenses (such as the kind you can leave in for two-weeks at a time) experience this problem much more often. However, with the invention of more permeable substances, contact lenses (such as Acuvue Advance or Night & Day) are much more permeable to oxygen and help reduce the risk of corneal neovascularization.\n\nThe symptoms of corneal neovascularization include diplopia (double vision), eye pain, redness, or minor yet noticable problems within the visual field. If you are a contact lens wearer then routine eye examinations by optometrists or ophthamologists should include screening for corneal neovascularization. The healthcare professional should be able to easily appreciate fine, irregular vasculature permeating into the cornea on one or both eyes.\n\nCorneal neovascularization is a serious problem and can lead to permanent damage to the eye. Treatment for mild cases includes switching the patient to glasses or another type of contact lens. Severe cases, however, may require corneal transplantation.
622893
They have protein deposits on them from your tears so they are less effective to correct your sight.  Non-disposable contact lenses need to be soaked in a very nasty enzyme solution at least once a week to get rid of the protein deposits.
30713
Wearing contacts are a difficult adjustment for your eyes.  They must get used to a foreign body residing there.  Your doctor or optician likely recommended wearing them for short periods initially, working your way up to wearing them all day.  Have you been doing that?  If not, it could easily tire and irritate your eyes.  Giving your eyes some rest from the contacts may be enough to solve the problem.  Also, an over-the-counter eye care product may help as well.\n\nIf you are following their instructions and continue to have problems, you should probably return and have your eyes checked to make sure there are no other problems.
728593
i actually tried that before when i wasnt wearing my contacts....and yes you can see better if you squint really hard...its pretty neat u should try it sometime and see for yourself!
445458
Carrots. Because they contain vitamins and rabbits don't wear glasses! Sorry couldn't resist! \n\nTry eye drops if your eyes are too dry. Also go to your optician and check that your eyes haven't deteriorated. You may need stronger glasses or a different type.
448811
I have very sensitive eyes and have never been able to wear my contacts over night.   A couple times I've fallen asleep with them in.  It wasn't a nice experience.  It might be because they are toric lenses too...  Careful you don't get some odd eye infection leaving them in too long.
333342
It's not an economic ploy.  The material that they make 2 week contacts out of really isn't designed to last much longer than that.  A lot of it depends on your individual tear chemistry and eye health as well.  Some people are able to wear 2 week lenses for 3 or even 4 weeks, but only under the direction and supervision of their eye doctor.
1133142
Sure the contacts could be affecting you because your eyes "breathe" differently with and without contacts.  My eyes are always irritated when I take my contacts out - all the sudden they are getting a little more oxygen than they're used to and have no barrier from irritants.  I love my oasis lenses because I can keep in for a week before taking out to clean, which means fewer occassions for taking out and getting dry eye.  Try em and ask your eye doc just to be safe!
958981
Encyclopedia - Contact Lenses  \n\nWhen were contact lenses developed?\nWhat types of lenses are available?\n\n\nContact lenses are thin, finely crafted plastic discs designed to fit over the cornea (See Anatomy of the Eye) of the eye, usually to correct vision problems caused by refractive error. They are held in place by a natural layer of tears on the surface of the eye. In addition to their obvious cosmetic advantages over eyeglasses, contact lenses provide better peripheral vision and virtually eliminate the image distortion sometimes caused by eyeglasses. Contact lenses are now available for the correction of most vision problems caused by refractive defects of the eye including nearsightedness, farsightedness, astigmatism, and presbyopia. \n\nWhen were contact lenses developed?\nContact lenses were first described and sketched by Leonardo da Vinci in the early 1500s, and the first workable model - a 1/4-inch-long glass tube filled with water and containing a microscopic lens - was developed and used by Thomas Young in 1801. In 1887, a German glassblower produced the first see-through eye covering, and in 1888 two European researchers simultaneously reported using contact lenses to correct optical defects. \n\nIn 1929, Hungarian physician Dr. Joseph Dallos perfected a method of making molds from living eyes. This enabled the manufacture of lenses that, for the first time, conformed to the actual shape of the eye. William Feinbloom, a New York optometrist, made the first American contact lens and also introduced the use of plastic to the manufacturing process. Contact lenses were made an official part of the practice of optometry in 1945 when the American Optometric Association formally recognized contact lens fitting as an integral part of their profession. \n\nThe first soft contact lenses were developed in 1960, but weren't generally available to the public until 1971. Toric lenses for astigmatism were approved in 1978 and the first rigid gas permeable (RGP) lenses became available in 1979. The next decade saw many advances including the introduction of tinted lenses, bifocal lenses, daily wear soft lenses, disposable lenses, and extended wear RGP lenses. The 1990s saw more advances including disposable tinted lenses, daily disposable lenses and the first disposable lenses that included protection against ultraviolet sunrays. \n\nWhat types of lenses are available?\nContact lenses are generally categorized as "hard" lenses or "soft" lenses. As the name implies, hard contact lenses are manufactured from a rigid material, polymethylmethacrylate (PMMA). PMMA is a tough, clear material that was the original plastic used in the development of contact lenses. In modern hard lenses, PMMA is often combined with other plastics to increase the oxygen permeability. These are called rigid gas permeable (RGP) lenses. Soft contact lenses are made from a plastic hydrogel polymer, hydroxyethylmethacrylate (HEMA) and have a high water content. \n\nIn addition to being categorized as either "hard" or "soft," contact lenses may also be identified by their "wearing" characteristics (extended wear, daily wear, disposable, etc.) and according to the type of prescription (toric, aspheric, bifocal, etc.). The following descriptions are those generally used by the ophthalmic community in describing the various types of contacts lenses. \n\nDaily wear soft lenses\nThese lenses are made of flexible, soft plastics that allow oxygen to pass through to the eye. They are easy to get used to and comfortable to wear. Because they fit close to the eye and are more difficult to dislodge, they are often recommended for sports. They won't work to correct all vision problems and may not provide the sharp vision required by some wearers. They also require daily removal and cleaning. \n\nDisposable soft lenses\nDisposable soft lenses are normally worn for one or two weeks and then discarded. They are
728342
Different animals see different ranges of color.  Scientists can determine this largely by looking at the structure of the eye, to understand what light waves a structure responds to.
39727
Consider laser vision correction or contact lenses
1038945
If I remember correctly, the contacts that were recalled were the weird cosmetic ones that, for whatever reason, didn't require a prescription... they were the ones that had things like swirls and cats-eyes.\n\nTinted lenses from a big-name company that you buy from your optometrist are probably going to be fine.
172069
If you're looking to buy them without a prescription, you should know that ill-fitting contacts can lead to serious eye problems.  Contacts are medical devices that need to be fit specifically to your eyes (they aren't a one-size-fits-all kind of thing).  Even if you don't need a prescription to help you see better, you do need a prescription for the lens itself.  Your best bet is to make an appointment with your eye doctor.