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  • Exophthalmos

    serch.it?q=Exophthalmos

    Exophthalmos (also called exophthalmus, exophthalmia, proptosis, or exorbitism) is a bulging of the eye anteriorly out of the orbit. Exophthalmos can be either bilateral (as is often seen in Graves' disease) or unilateral (as is often seen in an orbital tumor). Complete or partial dislocation from the orbit is also possible from trauma or swelling of surrounding tissue resulting from trauma. In the case of Graves' disease, the displacement of the eye is due to abnormal connective tissue deposition in the orbit and extraocular muscles which can be visualized by CT or MRI. If left untreated, exophthalmos can cause the eyelids to fail to close during sleep leading to corneal dryness and damage. Another possible complication is a form of redness or irritation called "Superior limbic keratoconjunctivitis", where the area above the cornea becomes inflamed as a result of increased friction when blinking. The process that is causing the displacement of the eye may also compress the optic nerve or ophthalmic artery, leading to blindness.

  • Retinal detachment

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    Retinal detachment is a disorder of the eye in which the retina separates from the layer underneath. Symptoms include an increase in the number of floaters, flashes of light, and worsening of the outer part of the visual field. This may be described as a curtain over part of the field of vision. In about 7% of cases both eyes are affected. Without treatment permanent loss of vision may occur. The mechanism most commonly involves a break in the retina that then allows the fluid in the eye to get behind the retina. A break in the retina can occur from a posterior vitreous detachment, injury to the eye, or inflammation of the eye. Other risk factors include being short sighted and previous cataract surgery. Retinal detachments also rarely occur due to a choroidal tumor. Diagnosis is by either looking at the back of the eye with an ophthalmoscope or by ultrasound. In those with a retinal tear, efforts to prevent it becoming a detachment include cryotherapy using a cold probe or photocoagulation using a laser. Treatment of retinal detachment should be carried out in a timely manner. This may include scleral buckling where silicone is sutured to the outside of the eye, pneumatic retinopexy where gas is injected into the eye, or vitrectomy where the vitreous is partly removed and replaced with either gas or oil. Retinal detachments affect between 0.6 and 1.8 people per 10,000 per year. About 0.3% of people are affected at some point in their life. It is most common in people who are in their 60s or 70s. Males are more often affected than females. The long term outcomes depend on the duration of the detachment and whether the macula was detached. If treated before the macula detaches outcomes are generally good.

  • Near-sightedness

    serch.it?q=Near-sightedness

    Near-sightedness, also known as short-sightedness and myopia, is an eye disorder where light focuses in front of, instead of on, the retina. This causes distant objects to be blurry while close objects appear normal. Other symptoms may include headaches and eye strain. Severe near-sightedness increases the risk of retinal detachment, cataracts, and glaucoma. The underlying cause is believed to be a combination of genetic and environmental factors. Risk factors include doing work that involves focusing on close objects, greater time spent indoors, and a family history of the condition. It is also associated with a high socioeconomic class. The underlying mechanism involves the length of the eyeball growing too long or less commonly the lens being too strong. It is a type of refractive error. Diagnosis is by eye examination. Tentative evidence indicates that the risk of near-sightedness can be decreased by having young children spend more time outside. This may be related to natural light exposure. Near-sightedness can be corrected with eyeglasses, contact lenses, or surgery. Eyeglasses are the easiest and safest method of correction. Contact lenses can provide a wider field of vision, but are associated with a risk of infection. Refractive surgery permanently changes the shape of the cornea. Near-sightedness is the most common eye problem and is estimated to affect 1.5 billion people (22% of the population). Rates vary significantly in different areas of the world. Rates among adults are between 15 and 49%. Rates are similar in males and females. Among children, it affects 1% of rural Nepalese, 4% of South Africans, 12% of Americans, and 37% in some large Chinese cities. Rates have increased since the 1950s. Uncorrected near-sightedness is one of the most common causes of vision impairment globally along with cataracts, macular degeneration, and vitamin A deficiency.

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