Macular oedema

The macula is located in the centre of the retina, the area at the back of the eye that receives light and transmits it to the brain as electrical signals. The macula’s job is to use millions of light-sensitive cells to provide clear, central vision. By affecting the macula in the retina, macular oedema, due to the accumulation of fluid, stops the macula from functioning properly and causes blurred vision. If the macula is damaged, so is your central vision, which usually becomes blurred, distorted or darkened.

Macular oedema causes fluid to leak from the affected blood vessels and interferes with the vision of small objects and colours.

Symptoms of macular oedema will vary depending on how badly the macula is swollen and whether the lesion is in one or both eyes.

Most people will notice one or more of the following symptoms:

• Blurred or “wavy” vision;
• Vision loss/difficulty reading;
• “Washed-out” colours.

If you have any of these symptoms, contact an eye specialist as soon as possible. Severe macular oedema, if left untreated, can lead to permanent and severe visual impairment.

If you have diabetes, you may be at risk of developing diabetic macular oedema. Although the symptoms will be similar to those listed above, they are more likely to occur in both eyes rather than one.

As with other diabetes-related eye diseases, it is advisable to have regular eye examinations so that your eye specialist can monitor your eye condition.

Macular oedema is not a disease in itself, but rather a consequence of other diseases or eye injuries that cause fluid to accumulate in the macula.

Common causes:

• Diabetes – high blood sugar levels weaken blood vessels, which can leak fluid into the macula;
• Macular degeneration is a common cause of vision problems as we age. Age-related macular degeneration comes in two forms: wet and dry;
• Inherited/genetic diseases – pigmentary retinitis pigmentosa is a common example;
• Inflammatory eye diseases – anything that causes inflammation and swelling in the eye can affect the macula;
• Surgical intervention – macular oedema can be caused by cataract, glaucoma or retinal surgery;
• Medications – be sure to warn your eye specialist about all medications you are taking, as some of them can cause side effects that lead to macular oedema.

To get a good look at the retina, your eye specialist will dilate your pupils and use a magnifying lens to better examine the back of your eye. He or she will also check your vision, measure your intraocular pressure with a tonometer, and may perform an optical coherence tomography (OCT) to see if there is any swelling on the retina.

Diabetic macular oedema doesn’t always cause obvious symptoms, so it’s a good idea to have your eyes checked regularly, or visit an eye specialist if your vision has changed.