The delicate eye is susceptible to a plethora of disorders and diseases, many of which can be prevented. Yet, a number of these disorders are not caused by lifestyle or trauma, but by genetic inheritance. Three common hereditary eye disorders are glaucoma, strabismus, and nystagmus. 

Glaucoma

Glaucoma affects an estimated millions of Americans, many of whom are unaware that they have the disease. It occurs when fluid pressure builds in a person's eye because of the eye's inability to drain properly. This causes damage to the optic nerve and eventually results in blindness.

There are several different types of glaucoma, including normal-angle glaucoma, closed-angle glaucoma, and secondary glaucoma, but the most common type is called primary open-angle glaucoma. This type of glaucoma is diagnosed when the eye's drainage canals are blocked, disallowing the drainage of regularly occurring, normal inner eye fluid. Primary open-angle glaucoma is not only the most common form of the disease, but also a highly inheritable one. Those most likely to inherit primary open-angle glaucoma are:

• Of Hispanic or African American descent; 
• Closely related to someone already diagnosed with the disease; or
• Have a family history of cardiovascular disease or diabetes.

Because the symptoms of glaucoma are usually not prevalent until after vision loss or severe eye damage occurs, those who are genetically predisposed to the disease should regularly schedule eye exams with an ophthalmologist. The ophthalmologist will perform a set of exams, such as an eye pressure test and optic nerve evaluation, that will help determine whether the early stages of glaucoma have begun. If caught early, the ophthalmologist can develop a treatment plan and prevent further damage or vision loss.

Strabismus

Affecting approximately 4% of Americans, strabismus is an eye disorder identified by the eye muscles' inability to function together. As a result, the eyes cannot focus on the same thing at the same time, so the nerves send two different images to the brain. Left untreated, the brain will pay attention to images received from the "stronger" eye, which will take over and cause the other to become "lazy."

Sometimes referred to as "crossed eyes," strabismus can result from trauma or other disorders, like Down syndrome or cerebral palsy. In most cases, however, it is inherited. Parents of children with a family history of strabismus and parents of children with obvious eye muscle mismatching should schedule an appointment with an ophthalmologist. During the exam, the ophthalmologist will examine the child's eyes and determine an appropriate treatment plan. Sometimes, prescription glasses or an eye patch is all that is needed to remedy strabismus, but sometimes surgery is the only option.

Nystagmus

Nystagmus is another eye disorder identified by improper eye muscle function. People with nystagmus will have one or both eyes that involuntarily jerk either side to side or up and down, causing debilitating vision problems. The disorder can occur after trauma or because of another disease, but it is usually inherited. 

Approximately 10-20% of children with nystagmus do not experience other congenital eye disorders. The majority of people affected by nystagmus are also afflicted by other inheritable eye disorders, like albinism, lack of an iris, and optic nerve hypoplasia. 

Expecting parents can request genetic testing in order to determine whether the child is at risk for inheriting nystagmus. After the child's birth, a parent also has the option of meeting with an ophthalmologist at a place like Blue Ridge Ophthalmology for an eye evaluation, which can be scheduled as early as eight weeks (when symptoms are most likely to begin).