What role does family history play in the development of eye conditions?
You may wonder why your optometrist is interested in finding out what eye conditions other members of your family have experienced. Many common vision issues and eye diseases are passed on genetically and can be inherited from parents, grandparents and previous generations. Because many of these eye diseases take a while before they are noticed, arming your optometrist with information on your family history allows them to know what symptoms to look out for.
What are some of the vision problems you can inherit?
There are some vision issues that are most common that are caused by refractive errors. These problems are caused by changes in the shape of our eyes that prevent light from focussing properly on the retina. The most common refractive errors are:
- Myopia. Short-sightedness is the inability to focus on objects in the distance caused by elongation of the eye.
- Hyperopia. Long-sightedness, due to a shortening of the eye, is the inability to focus on objects near at hand.
- Astigmatism. An irregular curvature of the cornea affects your ability to focus on objects both near and far away.
There are other less common conditions that are also believed to be inherited, such as strabismus, commonly referred to as cross-eyed, where a person’s eyes are not aligned properly, and amblyopia, where one eye is weaker than the other. This is commonly known as lazy eye.
Usually with these conditions, the eye itself is healthy and the only issue experienced is difficulty in seeing clearly.
What are the more serious eye diseases that can be passed on genetically?
There are, however, some more serious eye conditions that are passed on genetically that can threaten the health of your eyes and lead to loss of vision and blindness. Some of these develop as you age.
- Age-Related Macular Degeneration (AMD). The macular is responsible for your sharp central vision. AMD causes the macular to become damaged and causes dark or blurred spots in your centre of your vision. If you have a close relative with AMD, you are significantly more likely to suffer from the condition yourself. In fact, 1 in 5 AMD sufferers have an affected parent or sibling.
- Glaucoma. An eye disease where increased eye pressure can cause damage to the optic nerve interfering with the signals sent from the eye to the brain. The first symptom is usually loss of peripheral vision, but by the time this is discovered, considerable damage has already occurred. If you have a family history of glaucoma, you are 4 to 9 times more likely to develop this disease.
- Cataracts. Caused by the breakdown of proteins in the lens, the cloudiness created interferes with light reaching the retina with resultant blurriness and loss of vision. Whilst they are not always passed on genetically, some inherited conditions make you more at risk of developing a cataract.
- Retinitis Pigmentosa. This is a degenerative disease of the retina that affects the retina’s ability to respond to light making it difficult to see in low light and causing gradual vision loss.
- Diabetic Retinopathy. This is a complication of diabetes that can lead to blindness where the tiny blood vessels in the retina are damaged. Type 2 diabetes is caused by a genetic mutation.
What about eye diseases that cause blindness in babies and young children?
Some of the eye diseases mentioned above can also affect young children and over 60% of disease that causes blindness in infants is known to be inherited. These diseases include congenital cataracts, congenital glaucoma, retinal degeneration, eye malformations and optic atrophy. Retinitis pigmentosa is also known to develop in early childhood.
Having a family history of eye disease does not automatically mean that you will develop it also. Knowing what symptoms to look out for ensures that any diagnosis is made early allowing the condition to be treated and managed. Also, steps can be taken to minimise any other risk factors, such as lifestyle, health and diet.
Make sure to attend your yearly eye examinations with your optometrist. As many of these eye diseases don’t have any early warning signs, discovering and treating them early will help to reduce the risk of significant vision loss.