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Retinal Inflammatory Diseases

  • Presumed Ocular Histoplasmosis
  • Toxoplasmosis
  • Uveitis

Ocular Histoplasmosis

Ocular Histoplasmosis is a major cause of visual impairment in the eastern and central United States where 90 percent of adults have been exposed to histoplasma capsulatum. This common fungus is found in molds from soil enriched with bat, chicken or starling droppings and yeasts from animals.

Although the fungus is not found directly in the eye, people with Ocular Histoplasmosis usually test positive for previous exposure to histoplasma capsulatum.

Histoplasmosis is usually mistaken for a cold. The symptoms are very similar. The body's immune system normally overcomes the infection in a few days. The only evidence of histoplasmosis is histo spots, tiny scars on the retina. Generally histo spots do not affect vision, but for unknown reasons, some people can have ocular complications years or decades later.

Doctors believe that the histoplasmosis spores travel from the lungs to the eye where they settle in the choroid, the layer of tiny blood vessels that provides blood and nutrients to the retina, the light-sensing layer of cells lining the back of the eye.

Ocular histoplasmosis develops when fragile, abnormal blood vessels grow under the retina. The abnormal blood vessels form a lesion known as choroidal neovascularization (CNV). If left untreated, the CNV lesion can turn into scar tissue and replace the normal retinal tissue in the macula.

Toxoplasmosis

Toxoplasmosis is a common parasitic infection. When contracted by a pregnant woman, toxoplasmosis can pose serious risks to the unborn baby. Simple precautions can reduce the chance of infection.

Pregnant women should avoid handling litter boxes and eating raw meat because the parasite may originate in cat feces or undercooked meat. If acquired during the first trimester of pregnancy, the infection can be devastating to an infant.

Toxoplasmosis affects the retina, the light-sensitive cells lining the back of the eye. Both eyes are usually involved. If the infection settles in the macula, the area of the retina responsible for central vision, good vision is lost forever.

When toxoplasmosis heals, it leaves a scar. The infection may recur years later, sometimes near the previously infected area. Swelling that fights the infection may cause floating spots in one's vision, red, painful eyes, and poor vision.

Uveitis

Uveitis means "inflammation of the uvea", or the middle layer of the eye. The uvea consists of three structures: the iris, the ciliary body, and the choroid. The iris is the colored structure surrounding the pupil, visible in the front of the eye. The ciliary body is a structure containing muscle and is located behind the iris which focuses the lens. The choroid is a layer containing blood vessels that line the back of the eye and is located between the inner visually sensitive layer, called the retina, and the outer white eye wall, called the sclera. Inflammation occurring in any of these three structures is termed "uveitis".

Inflammation in uveitis may involve any but not necessarily all of these three structures. Depending upon which structures are inflamed, uveitis may be further subcategorized into one of three main diagnoses, these include:

  • iritis or anterior uveitis,
  • iridocyclitis or intermediate uveitis, and
  • choroiditis or posterior uveitis.

Uveitis may develop following eye trauma or surgery, in association with diseases which affect other organs in the body, or may be a condition isolated to the eye itself. Severe and permanent visual loss can result from uveitis. In addition, uveitis can lead to other ocular complications, which may produce vision loss, including glaucoma, cataracts, or retinal damage. Early detection and treatment is necessary to reduce the risk of permanent vision loss.

Symptoms

Depending on which part of the eye is inflammed in uveitis different combinations of these symptoms may be present.

  • Redness
  • Light sensitivity
  • Floaters
  • Blurry vision
  • Pain

These symptoms may come on suddenly, and you may not experience any pain. The symptoms described above may not necessarily mean that you have uveitis. However, if you experience one or more of these symptoms, contact Dr. Fern for a complete evaluation.

Treatment may include steroid eyedrops, injections, or pills, as well as eyedrops to dilate the pupil and reduce pain.

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