Types of contact lenses
There are several types of lenses: daily, monthly replacement, for three months or more. Most of them are intended for daily wear, that is, they need to be removed before going to sleep maximum after fifteen hours of wear. In the instructions to the lenses necessarily written about the mode of wearing them, even if the doctor told you that these lenses can go a few days without taking off, but the manual suggests otherwise, follow the instructions, otherwise there may be problems with the health of the eyes. Do not risk the health of their eyes, even if before bed you did not have a container with the solution. Better to buy a new lens than to treat the consequences.
There are lenses extended wear, which can be a long time to remove: for example, a five-day or weekly. They are released to the company Bausch&Lomb and Ciba Vision. Ophthalmologists do not recommend to use them without the need of, but if you opted for them, should not be on during the entire specified on the packaging of the period wearing the lenses without removing even at night. Let your eyes rest even during sleep, it is advisable to do this every few days.
Using these lenses for the first time, increase the wearing time gradually, starting with two to three days.
Harm from sleeping in the lenses
Even if the contact lenses are designed for continuous day and night wear, it does not mean that they do not have harmful effect on the eye. Despite the advent of modern materials with high permeability for oxygen to be breathable and 100%, as stated in the advertisement, lenses can't. They get a part of the oxygen, the eyes begin to dry, there is a burning sensation, discomfort.
Answering the question, is it harmful to sleep in the lenses, you need to consider not only the type of lenses and the human eye. Depending on the amount of protein in tear, from the eye health of their sensitivity sleep in the lenses has different effects. Some people do not notice the presence of a foreign body in the eye and even after several days of continuous wear not feel discomfort, even in the most high-quality, "breathable" modern lenses for extended wear can't sleep without discomfort.
If you feel eye pain, dryness, burning, noticed redness of the eye, immediately remove your lenses.
Environmental conditions, humidity and cleanliness of the premises in which the person sleeps, and other factors also affect what the effect of the lens on the eye.