The contact lenses are your medical boon, which help you to overcome your sight problems. You need them to correct tour sight and at the same time to maintain your eyesight. The contact lenses do not always work in the same fashion for everyone. Your success depends much on your regularity in its usage and if you follow the doctor's instructions to the T. Doctors advise you to take off the contact lenses when you retire to bed at night. The tears in your eyes are the oxygen suppliers to your cornea. However, when you sleep, the eyes secrete much less tears and hence your cornea swells up. This together with the pressure of the lenses depletes the oxygen supply and your eye is now more open to any sort of infection. The contact lenses help to shape your cornea to some extent. Just as more of anything is always bad and harmful, so also wearing the lenses for longer periods will hamper the shape and cause harm to your eyes. You should clean your lenses daily with proper disinfectants in as the same way as your doctor advises you. Otherwise, you are opening up your eyes for bacterial infections and even ulcers of the cornea. There are two types of contact lenses-soft and rigid. Soft lenses work softly on your cornea and allow water to permeate in easily, thereby increasing oxygen supply to your cornea. Some of these are of the disposable kind or even as replacements. Rigid lens are a bit strenuous on your eyes and it will take you a long time to be able to adjust to it. You can mark the lens for each of your eyes and can count of them to view things clearly. Whatever may be the type of contact lenses, they offer you corrective vision with chances of improving on the same. Always keep in mind to get your lenses with a doctor's prescription only. Get your eyes checked with a reputed ophthalmologist and follow it up with regular visits. Clean, maintain and use the lenses as per the doctor's advice and you are sure to enjoy much more happy viewing.