examination to rule out any other potential problem such as infection or allergy. A lens case with solution should be carried if the lenses need to be removed during the day, since wearing a lens longer than it is comfortable can lead to disaster. One should never put a contact lens in tap water, or in solutions not designed for lens storage or disinfection. It is also unwise for a contact lens wearer to use solutions other than those recommended by their optometrist.Wearing ProblemsContact lenses are better at correcting certain types of vision problems than others can correct. Simple nearsightedness or farsightedness is usually easily corrected using contact lenses, but astigmatism can be more challenging to correct, especially with soft lenses. Contact lenses have varying success in correcting the need for reading glasses, with bifocal contact lenses rarely being successfully prescribed.Toric soft lenses have an astigmatism correction built into the lens, but rotation of the lens can lead to a shifting of the astigmatism correction, and temporarily blurred vision. For people with severe or irregular astigmatism, rigid gas-permeable lenses (RGPs) or hard lenses may offer better visual results. Irregular astigmatism is a situation where the cornea is distorted due to a scar or underlying disorder. Sometimes rigid contact lenses are the ONLY way to correct the vision in these cases, as even glasses will not help (as in keratoconus).Many people who use contact lenses may experience halos around lights at night, and sometimes ghost images. This probably is a normal phenomenon in most people, and occurs when the pupil is larger (or more dilated) than the optical area of a soft lens, or of the lens itself in cases of rigid lenses. However, seeing a rainbow around lights indicates swelling of the cornea (corneal oedema), and indicates that the lenses have been in too long and should be removed.Blurred vision in one eye or the other with a c...
