Of the nearly 2,000 genes discovered to date, approximately 500 of them affect the eye. Through a program called the National Ophthalmic Disease Genotyping Network (eyeGENE), the NEI is expanding genetic testing of eye disease. The eyeGENE program is a network of research labs that offers testing for affected individuals. EyeGENE will also create more data from which investigators can identify additional genetic risk factors. The network will also explore the relationship between a genetic disease and its clinical manifestations. Understanding the genetic link will help researchers develop tailored therapies to halt a disease or reduce its impact.
Recently, a gene therapy trial supported by NEI showed great promise in treating a form of childhood blindness. The condition, called Leber congenital amaurosis, is caused by a single malfunctioning gene. Symptoms usually occur in early infancy and include loss of vision, reduced sensitivity to light, and wobbly eye movement (nystagmus). The gene transfer surgery involves inserting a hollow needle into the space between the eye's retinal layers and transferring genetic material via a fluid from the needle. The first three patients were treated in October and December 2007 and January 2008 and so far have experienced no adverse effects. "These are heroic young people," says Samuel Jacobson, a University of Pennsylvania researcher involved with the study. "[The treatment] causes changes that they notice." Although no one can predict the future, Jacobson's hope is that in three to five years the patients' gain in vision will be maintained.
Eye Exams Throughout Your Life
Complete Eye Examination
What: To examine your vision and health of your eyes, your eye care professional will:
1. Ask about your overall health and family medical history, including whether you have any eye problems;
2. Check your visual acuity using a chart of random letters of different sizes;
3. Examine the cornea and other parts of the eye. Look inside your eye with a lighted magnifying glass to see the retina, back of the eye, retinal blood vessels, and head of the optic nerve (optic disc). You may be given eye drops so the doctor can better view the back of the eye. This is called eye dilation;
4. Test your eye's reaction to light, eye movement, and side (peripheral) vision;
5. Determine if you need glasses by placing several lenses in front of your eyes, one at a time, and asking you when the letters on the eye chart are easier to see;
6. Test for color blindness using multicolored dots that form numbers; and
7. Measure the pressure inside the eye using a tonometer. Pressure inside the eye is a risk factor for glaucoma.