Many times, people assume they only need to be aware of and on the lookout for common eye diseases, like glaucoma and macular degeneration. However, these are not the only eye diseases around. There are also some less-common diseases. The fact that you are less likely to get these particular diseases does not mean you won't get them -- so it's still wise to be informed about their existence. To that end, here are three "rare" eye diseases to watch out for.

Usher Syndrome

Usher syndrome is a condition that affects both hearing and eyesight. It's a genetic condition that is present at birth, so if you do not already have it, you won't get it -- but your children might get it. It is a recessive trait, so you can unknowingly pass it on to your child even if you do not have it. The way it presents varies somewhat. Some children are born completely deaf and with serious visual impairment, and others are born with a more mild form of hearing and vision loss. There is no cure for the condition, but there are therapies, listening devices, and other treatments to help manage the symptoms.

Retinoblastoma

Retinoblastoma, as the name suggests, is a cancer that affects the eye. It usually appears in childhood, but some people don't develop symptoms until they are older. The condition causes redness, swelling, and a whitish spot in the middle of the eye. As the condition progresses, it leads to vision loss, as it affects the optic nerve directly. Retinoblastoma can be passed from parent to child, but it can also occur due to a genetic mutation. If the condition is caught early, there are treatments to delay its progression and preserve vision.

Anophthalmia

Anophthalmia is another genetic condition that people are born with. So if you don't have it now, you won't get it -- but your child may be born with it. The disease's name means that one or both eyes are absent. Sometimes, children are born with some eye tissue or an eyelid, but not a fully formed eye. Other times, the eye socket may be completely absent. There is no cure, and whether or not the child has any vision will depend on the extent of the ailment.

Now that you know a bit more about these eye diseases, you will be more prepared to deal with them if they arise in your children or in the children of a friend. To learn more, contact an ophthalmology clinic near you.