Many eye disorders “run in families” and are genetic — that is to say, they are passed on from parents to their offspring by genes. We also say these conditions are hereditary and that those who are affected have inherited the condition. It is possible to test someone’s genes to look for changes that can cause an eye disease and that is one type of genetic testing. These changes to genes are called mutations. To do this test, a sample of blood is collected from the arm, just like at your annual physical exam, and sent to a laboratory where it is analyzed. The results are returned to the doctor and then discussed with the patient or family. Genetic testing may be helpful in many ways. Here are some of them:

• It can establish a definite diagnosis that might not be possible otherwise
• It might rule out a condition that your eye doctor was considering since some can look very much like each other
• It can identify people who might be eligible to participate in a clinical trial, or a new treatment
• It might help determine how the condition will progress since different gene mutations affect people differently

Some other possible outcomes:

• Sometimes, nothing is found with genetic testing and you need to be prepared for that possibility
• Genetic testing may confirm that a person has a specific disease that they were hoping they did not have and that can cause distress
• Genetic testing may confirm that a parent has passed the disease to an offspring and that can be distressing