Low vision is a "medical term that is defined as chronic disabling visual impairments that cannot be corrected with glasses, contact lenses or medical or surgical treatment" according to Dr. Robert Massof, professor of ophthalmology and neuroscience. (See Reference 1) There are two criteria used for diagnosing low vision. Low vision maybe determined by the visual acuity score your child receives on an eye chart. A reading of 20/70 or poorer in both eyes that is uncorrectable with treatment indicates low vision. Low vision may also be defined as any vision loss that cannot be corrected and interferes with routine functioning. (See Reference 2)
Retinopathy of Prematurity
Retinopathy of prematurity, or ROP, was once known as retrolental fibroplasia. (See Reference 3) Premature birth can disrupt the normal development of blood vessels in the eyes. Blood vessels may leak blood into the eyes, causing scar tissue to build up. The pressure from this scar tissue can cause retinal detachment and vision loss. In the past, many premature infants were at risk for ROP due to the excessive use of oxygen. Today, better methods of oxygen regulation are available, and those numbers have decreased. The risk of developing ROP is now associated with the degree of prematurity. If your infant weighed less than 3 pounds or was younger than 30 weeks gestation at birth, she has an increased chance of ROP and should have her vision screened. (See References 3 & 4)
Retinal Detachment
As images come into the eye, the retina converts them into impulses and sends them on to the brain by way of the optic nerve. In retinal detachment, the retina is separated from the back of the eye, cutting off communication between the eye and retina. Retinal detachment can be caused by either illness or injury. Trauma to the eye can lead to detachment. Complications from diabetes is another cause of this condition. Sometimes, however, a cause for the detachment can't be determined. Symptoms of a retinal detachment include bright flashes of light, blurred vision, eye floaters or an area of shadow or vision loss. If your child sustains an eye injury or experiences any of these symptoms, seek medical treatment immediately. Successful reattachment may be surgically possible if the condition is diagnosed promptly. (See References 3 & 5)
Retinitis Pigmentosa
Retinitis pigmentosa is an inherited disorder. It causes progressive degeneration of vital structures within the eyes, resulting in permanent vision loss. It may be seen alone or as part of another condition, such as Friedreich's ataxia, Usher syndrome and muscular dystrophy. Vision loss typically begins in childhood, presenting with night blindness. Peripheral vision loss, known as tunnel vision, begins after this. During adulthood, the extent of vision loss increases as the disease progresses. The result is permanent low vision or blindness. The rate and extent of vision loss can vary, often related to the presence of other conditions. (See Reference 3)
