Of course, it is really bad for eye health if you wear unclear contact lens. The most possible sign of wearing unclear contact lens is redness. It is easy to get redness in eye because of bacteria and virus on unclear contact lens. So you had better wash them up with storage syrup and store them well. Do not wear any dirty or expired contact lens to avoid being infected by them.
Well, of course, it will be bad to have unclear contact lenses, for it will just lead to some eye problems. Generally speaking, contact lenses are made of plastics, and that can just carry some dirty stuff into your eyes, if you do not clean them carefully. In that way, it will just irritate your eyes, leading to some eye infection. And then red eyes, watery eyes, itchy eyes can be possible. In some cases, blurry vision can be possible. In long term, it will just damage your eyes.
Actually there are too much side effects if you don't clean your contact lenses. Tear kills 90% of bacteria in eyes, but it can't kill all. Eyes are open everyday that they would get damages from sunshine, wind and dusts in the air. Because of the dusts, the contact lenses would get dirty too. Meanwhile, there is protein in tear which means to nourish eyes cells. After the whole day wearing, the protein gets accumulated on lenses. All the factors above would give you a strong grittiness and foreign body sensation, blurry vision and discomforts. So it is the no.1 rule for people wearing contact lenses to wash and clean the lenses everytime before and after the wearing, otherwise it would be very easy to get infection and inflammation. Meanwhile, if your eyes are infected, wearing unclear contact lenses will just make the situation worse. It is better to clean lens everytime.
If a wear do not clean the contact lenses as prescribed from doctor, it is more like to get keratitis. Wearing contacts and not taking care of them properly is the single biggest risk factor for keratitis. Keratitis is an infection that occurs when germs invade the cornea, the clear dome that covers the coloured part of the eye. The infection can cause pain, inflammation and scarring of the cornea. It can also lead to blindness.