Which of the Following Disorders Does Not Affect the Eye?

There are many types of eye conditions, but one disorder you should know about is conjunctivitis, also known as pink eye. It is a disease of the conjunctiva, the clear tissue that protects and keeps the eyelid moist. It is highly contagious, particularly among children, and causes blurred vision, itchy eyes, and discharge. Refractive eye disorders, such as nearsightedness and farsightedness, and astigmatism, lead to problems with focus and vision at all distances. Treatments for these conditions can include eyeglasses, contacts, and surgery.


Although cataracts do not affect the eye directly, they do affect the retina. They are a clouding of the lens, which focuses light on the retina and causes blurred or dim vision. Most cataract cases occur in older people but can happen to younger people as well. As with most things, your vision can be blurred if you have cataracts, so you should consult your eye doctor to learn about your treatment options.

Generally, cataracts do not affect your vision immediately, so you may be able to wait to have your cataracts removed. However, if they interfere with your daily activities, surgery may be recommended. Cataract surgery replaces the cloudy natural lens with an artificial lens, called an intraocular lens (IOL). The procedure is very safe, and 9 out of 10 people who undergo this surgery can see clearly afterwards.

Diabetic retinopathy

Although most diabetics do not notice the onset of symptoms, there are some who do. There are two types of diabetic retinopathy: proliferative retinopathy and nonproliferative retinopathy. In the former type, fluid leaks into the eye and changes the shape of the retina. Eventually, the fluid can cause blurred vision. In the latter form, diabetic fibrous tissue develops on the retina.

Diabetic retinopathy does not cause any symptoms in the early stages, but it can cause various complications. One complication of diabetic retinopathy is vitreous haemorrhage, where blood leaks into the main eye jelly. If the retina is not damaged, the bleeding can resolve by itself. However, in severe cases, the blood can damage the retina, resulting in complete vision loss.

Genetic eye disorders

Many hereditary eye disorders have been identified, ranging from conditions that affect the eye only to complex syndromes affecting the whole body. Heritable retinal degenerations and congenital cataracts are among the most common of these disorders. It’s estimated that one out of every 250 infants is born with a cataract, although it can also develop later in life. Heritable retinal degenerations are often the cause of blindness. Retinitis pigmentosa, a genetic disease of the retina, affects one in every 5,000 people in the United States.

Retinitis pigmentosa is caused by mutations in a protein called retinoschisis. This protein helps to hold retinal cells together. When this protein is missing, retinal cells can’t properly form and organize into cones and other structures. In addition to affecting the retina, affected individuals may have a spoke-wheel pattern on the macula. If this is the case, patients may have difficulty recognizing objects in the distance.

Retinal degeneration

A group of inherited vision disorders characterized by progressive degeneration of the retina, or light-sensitive membrane inside the eye, is referred to as retinal pigmentosa (RP). In most cases, peripheral vision declines with time, and central vision is generally preserved until the condition progresses to a stage where the remaining eye cells are no longer able to see clearly. Some forms of RP are associated with other disorders such as deafness, metabolic disorders, central nervous system and chromosomal abnormalities.

The cause of macular degeneration is not known, but it is believed to involve ageing in specific layers of the retina. There are two types of macular degeneration, dry and wet, with the former causing more severe visual loss than the latter. Approximately 90% of patients with macular degeneration have dry macular degeneration. About ten per cent develop wet macular degeneration. The two forms may develop simultaneously or in different stages.

Orbital tumours

Although orbital tumours do not affect the eye, they can cause vision problems and can require surgery. Different types of tumours are present in the orbit. Some are benign, while others can be malignant. Ossifying fibromas, fibrous histiocytomas, and rhabdomyosarcomas are common. Skin cancer on the eyelids can also develop in the orbit. However, metastatic tumours often spread to the orbit.

Lymphangiomas are common tumours of the orbit. They usually appear in the second or third decade of life, although they can also appear in early childhood. They are commonly conservatively treated, with the use of short courses of steroids. Occasionally, bleeding into the tumour may lead to rapid expansion. Rapid surgery is recommended if the tumour is causing vision loss or proptosis. It is important to have regular eye examinations to determine if the tumour is malignant or benign.