Macular telangiectasia-a disease of retina that causes loss of central vision

The macula is the small area in the centre of the retina (the light-sensing organ of the eye), which is responsible for central vision and allows seeing the fine details clearly. Macular telangiectasia is a condition that affects the tiny blood vessels around the fovea (the centre of the macula).

 

Macular telangiectasia have two types, and they affect the blood vessels differently:

  • Type 1 macular telangiectasia: The blood vessels become dilated forming tiny aneurysms (ballooning of the artery) causing swelling and damage to the macular cells. It usually affects only one eye.
  • Type 2 macular telangiectasia: This is the most common form of macular telangiectasia. In this condition, the tiny blood vessels around the fovea leak, become wide or both. In some cases, new blood vessels develop under the retina, and they can break or leak. The fluid that leaks from the blood vessels causes the macula to swell or thicken (condition is called macular oedema) affecting central vision. Scar tissue can form over the macula and fovea, causing loss of detail vision. Type 2 macular telangiectasia affects both the eyes.

Causes

Type 2 macular telangiectasia: This condition mainly affects middle-aged adults, and both men and women are equally affected. In those who had type 2 macular telangiectasia, it was found that a high proportion had hypertension (52%) and diabetes mellitus (28%), which suggests that long-term vascular stress (stress on blood vessels) may be the cause for the condition.

The condition is seen to run in some families, so there may be a genetic predisposition, but this is still not proven. In majority of the cases, no cause is found for the disease.

Type 1 macular telangiectasia: This is seen almost entirely in men, and the diagnosis is usually made around the age of 40 years. Type 1 macular telangiectasia is related to Coat’s disease, a rare childhood congenital disorder.

Symptoms

There may be no symptoms in early stages of the disease.

As the disease progresses, it can cause many symptoms such as blurring of vision, distorted vision, and loss of central vision. You will require brighter light to read or perform other activities.

Central vision deterioration progresses over a period of 10-20 years.

Macular telangiectasia does not affect the side vision and does not usually cause total (legal) blindness.

As macular telangiectasia has no symptoms in the early stages, it is important to get regular eye exams from an ophthalmologist to detect any macular problems as early as possible.

Diagnosis

 

  • Eye exam: Your eye doctor will perform a vision testing. A special test called Amsler grid may be performed to detect if you have any dark or wavy areas in your central vision.  Eye drops will be used to widen the pupils, and your doctor will use an instrument (ophthalmoscope) to see the retina and other areas at the back of the eye. Careful examination by the ophthalmologist can detect fine crystals (retinal crystals) in the central part of the macula, which is the sign of macular telangiectasia.
  • Optical coherence tomography (OCT): Light waves are used to create detailed images of the underlying structure of the eye structures including the retina. OCT images will show the thickness of retina and help the ophthalmologist to detect swelling and abnormal blood vessels.
  • Fluorescein angiography: A special dye is injected into a vein in the arm, and it spreads through blood vessels to different organs, including the eyes. Images are taken of the back of the eye as the dye passes the blood vessels in the retina. Any abnormal regions will be shown by the outline of the dye.

Treatment

Many treatments have been tried for macular telangiectasia, but none have shown to be effective in significantly improving vision. Most patients may not require treatment, and the condition rarely progresses to complete blindness.

  • Laser treatments: In some cases, laser therapy may be used to seal the leaking blood vessels, but these treatments are less preferred due to their potential to cause harmful secondary effects.
  • Injections into the eye: In some cases, steroids and others medications are injected into the eye to reduce the swelling and inflammation.
  • Anti-VEGF medications: Development of new abnormal blood vessels under the retina known as choroidal neovascularization is one the important complication of macular telangiectasia. This condition requires injections of medications belonging to the class of vascular endothelial growth factor inhibitors (anti-VEGF) into the eyeball. These medications inhibit the growth of abnormal blood vessels, prevent their leakage, reduce the swelling in the retina and improve vision in some.
  • Low vision aids: Those with vision loss due to macular telangiectasia can use low vision aids to make the optimal use of the remaining vision in the eye.

Next Steps

If you have dimness or blurring of vision or dark spots in your field of vision, consult an ophthalmologist for further evaluation.

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References

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  • Issa PC, Gillies MC, Chew EY, et al. Macular telangiectasia type 2. Progress in retinal and eye research. 2013;34:49-77.
  • American Academy of Opthalmology. Eye Health A-Z. Macular telangiectasia. Accessed at http://www.aao.org/eye-health/diseases/macular-telangiectasia on 27 September 2016.

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