Macular telangiectasia (MacTel) refers to a disease that involves the macula resulting in central vision loss. The macula is a tiny part located near the middle of the retina. It enables an individual to clearly see objects nearby such as someone’s face or text on a mobile phone.
Eyesight is sharpest in the fovea, one of the parts that make up the macula. If there are problems with the blood vessels around the fovea, MacTel will develop. Vision loss may progress over a 10-20 year period. MacTel does not affect peripheral vision. It also does not lead to total blindness.
Also Known As
- Idiopathic juxtafoveolar retinal telangiectasia (JXT)
- Idiopathic juxtafoveal telangiectasis (JFT)
- Type 1 MacTel – Here the blood vessels dilate. The dilation forms small aneurysms which cause the swelling of the macular cells. This type only occurs in one eye.
- Type 2 MacTel – It is the most common type. New blood cells may form under the retina, break or leak causing macular edema (swelling of the macula). Another manifestation of Type 2 MacTel is when the blood vessels around the fovea leak and dilate. Also, when scar tissue forms over the macula, it can lead to loss of detail vision. Type 2 MacTel involves both eyes even though the severity of the disease may not be the same for each eye.
Causes and Risk Factors
Causes for MacTel are largely unknown. However, it is believed that environmental factors and genetic predispositions may be responsible. The following are the risk factors associated with Type 2 MacTel:
- Middle-aged individuals
- Both men and women
- Those suffering from diabetes or hypertension
- Those with a family history of MacTel
- People with a coronary disease
The risk factors for Type 1 MacTel include:
- Coat’s disease – A rare congenital disorder found only in males
- People in their 40s
Signs & Symptoms
A sign of MacTel is the presence of fine crystals in the center of the macula. At the start of the disease, individuals with MacTel may present no symptoms. However, as the disease progresses, the following may manifest:
- Blurred or distorted vision
- Slow loss of vision
- Loss of central vision
- Trouble with reading
- Scotoma – An absent or deficient spot in the field of vision
- Parts of the central vision may appear blank
- Metamorphopsia where straight lines seem bent or wavy
Since MacTel progresses over a long period, there may be phases where the patient may experience no symptoms interspersed with worsening symptoms.
One should seek regular eye examinations because MacTel symptoms take long to manifest. The eye care professional may conduct the following assessments:
- Amsler grid testing to detect any dark or wavy areas in the central vision.
- Dilating the eye using eye drops to examine the retina and the back of the eye.
- Using optical coherence tomography (OCT) to take pictures of the retina to show its thickness. The images will help the professional detect any abnormal blood vessels and swelling.
- Fluorescein angiography where the professional injects a dye into the vein of an arm. He/she will then take pictures of the vessels as the dye travels in the bloodstream. This dye will highlight any abnormal issues with the macula or retina.
Treatment of MacTel aims to lessen the growth of abnormal blood vessels in the retina. It is also directed towards reducing the swelling in the macula.
In most cases, patients with MacTel do not need treatment. Researchers don’t seem to agree on the treatment that can cure MacTel. Currently, clinical trials are underway.
In some situations, MacTel can cause choroidal neovascularization (CNV). CNV refers to the growth of abnormal blood vessels on the retina. CNV is treated by a vascular endothelial growth factor inhibitors (anti-VEGF) injection. Anti-VEGF targets vascular endothelial growth factor, a chemical that causes the growth of abnormal blood vessels in the retina. The injection will reduce the growth of abnormal blood vessels. It will also slow down the leakage and help to decrease the swelling in the macula. Anti-VEGF can help to improve vision in some people.
The eye doctor can also treat MacTel with steroids and other medications.
Laser surgery can help seal leaking vessels. However, due to potentially harmful side effects, surgeons use it less frequently.
A patient can use low vision aids to help them make the most of their remaining vision. A MacTel patient can also use brighter light for such activities as reading.
Most people who develop MacTel do not need treatment since the disease tends to go away on its own. Some doctors think that treatment appears not to offer many benefits.