Vision Loss

Vision Loss

Vision loss is the impairment or total loss of sight due to disease, trauma, or certain other medical conditions. Common causes of vision loss include head trauma and diseases such as macular degeneration, cataracts, glaucoma, diabetic retinopathy.

Though vision loss may eventually lead to blindness, most of its victims will endure a condition called low vision for a long time before their sight fades completely. Low vision inhibits its victims to the point that it is difficult to perform routine activities such as reading, cooking, and watching television. It is never possible to correct low vision with lenses and rarely with surgery. There are, however, low vision aids that can effectively help with particular tasks.

The causes of vision loss

Age-related macular degeneration (AMD) is the main cause of vision loss. There are two types of AMD - wet and dry. Dry macular degeneration is more common. In this form, the tissue of the eye's macula gradually thins, causing mild central vision loss. There is not an effective treatment for dry AMD. Wet macular degeneration is less common but more debilitating. It causes new blood vessels to form on the macula. New and old blood vessels alike become fragile and leak, causing blind spots. Wet AMD can be treated with laser surgery or photodynamic therapy, though the disease must be caught fairly early for treatment to be effective. Even these procedures only succeed in pushing back the disease's progress, not reversing it.

A cataract is the clumping of protein within the lens of the eye. Cataracts cause the vision to slowly cloud, resulting in steadily worsening nearsightedness. Though this nearsightedness can be overcome with prescription lenses at first, cataracts often develop to the point of near blindness, requiring lens replacement. In this safe and effective procedure, the cloudy lens is replaced by a synthetic one. Cataracts can be caused by a number of factors, but are most closely associated with age.

Glaucoma is a disease that causes blind spots through damage to the ocular nerve. In most forms of glaucoma, this is caused by inhibited flow of the aqueous humor (fluid that nourishes the eye), which leads to high intraocular pressure (IOP). This intraocular pressure can be treated with either medication or surgery. After the surgery, the effects of the disease may subside a little, but significant nerve damage is likely permanent, and the IOP must be monitored to prevent further damage.

Diabetic retinopathy is a disease that causes clouding in the vision of diabetics. Their high blood sugar levels cause the blood vessels on the retina to leak. In later stages, new blood vessels may grow that can leak into the vitreous humor (fluid in the center of the eye). There are two surgical techniques that are used to treat diabetic retinopathy: laser photocoagulation and vitrectomy. In photocoagulation, the laser is directed at the retina to seal specific blood vessels and prevent the formation of new ones. In vitrectomy, the cloudy vitreous humor is removed and replaced with a clear solution. If performed early on, these procedures have positive effects, both in setting back the progression of the disease and in improving vision. They cannot, however, cure the disease.

Injuries to the head and eyes can also result in vision loss. These can occur during competitive sports, automobile accidents, accidents with chemicals, or any number of other situations.