Diabetic macular oedema (DMO)

Diabetic macular oedema (DMO) is a vision-threatening complication of diabetes. Diabetes is an illness which affects the body’s ability to control blood sugar levels. DMO is the most common cause of sight loss in people with diabetes. 

Macular oedema can also occur due to retinal vein occlusion, surgery, and other reasons. To understand more about these other causes, visit our macular oedema webpage.

When diabetes causes blood vessels to release blood and fluid into the eyes' macula, it is known as diabetic macular oedema.

DMO is painless. Macular oedema affects central vision, so a person's side vision is not effected. However, other forms of diabetic retinopathy may affect your wider vision.

Being diagnosed with DMO can be distressing, but with the right information and support, people can cope very well. This page explains how DMO is diagnosed, treated, and how to live with the condition.

Recognising early symptoms of diabetic macular oedema

In the early stages of diabetes, you may not notice any changes to your vision. Damage to the retina occurs over many years.

If blood vessels in or near the macula become damaged, or if sudden bleeding or fluid leaks into the macula, sight can worsen dramatically.

You may notice:

• Dark spots like a smudge on glasses.

• Gaps may appear in your vision, especially first thing in the morning.

• Objects in front of you might change shape, size, or colour or seem to move or disappear.

• Colours fade.

• Bright lights or glare is challenging.

• Difficulties reading.

• Straight lines, such as door frames and lamp posts, may appear distorted or bent.

If you notice a sudden change in your vision, contact your optometrist or hospital eye specialist urgently.

Visual hallucinations

Some people with conditions affecting their vision might experience visual hallucinations called Charles Bonnet syndrome. Visual hallucination is when you see things that are not really there. Hallucinations may include people, animals, landscapes, or patterns.

People who haven’t heard of Charles Bonnet syndrome often worry they are developing a mental health problem. However, this is a normal response of the brain to sight loss. If less visual information reaches the brain, your cells that normally process vision can create images of things that are not there.

Hallucinations may happen once or twice, or continue for years.

Dealing with visual hallucinations

Hallucinations can worsen when people are tired or stressed. If you are experiencing hallucinations, the following tips can be helpful:

• Change lighting. Make lights brighter if you’re in a dark place or move somewhere darker if you are somewhere bright.

• Move your eyes from side to side 15 to 30 times. Don’t move your head – just your eyes. Pause and repeat until the hallucinations go away.

• Get up and move to a different place.

• Turn on the television, listen to the radio, or make a phone call.

How diabetic macular oedema is diagnosed: tests and what to expect

If you have symptoms of DMO, you will be referred to the hospital eye department for tests. Your hospital specialist (ophthalmologist) may use:

• Eye drops to dilate the pupils to clearly see the back of the eye. Your pupils are the black circles at the centre of the eye where the light enters. The drops may make your vision blurred and sensitive to light for a short time. You will not be able to drive after having eye drops, so someone will need to take you home.

• Optical coherence tomography (OCT) scans to produce a cross-sectional image of the retina.

• Fluorescein dye angiography: a dye is injected into a vein in the arm. It travels to the eye, highlighting the blood vessels in the retina so they can be photographed. The dye will temporarily change the colour of your urine.

If you have any vision problems in between appointments, seek immediate advice from your diabetes care team or GP. Do not wait until your next hospital appointment.

Managing diabetic macular oedema: treatments, lifestyle changes, and support

DMO can be treated if caught early. Sometimes, mild DMO can improve on its own or with improvement in control of blood sugar and blood pressure. If direct treatment to the eye is needed, this is usually done with injections. Drugs are injected into the eye to stop fluid leaking from the blood vessels.

Injections

• Delivery method: Intravitreal injections are not as bad as they might sound. The eye is numbed and the needle goes into the corner of the eye, so you do not see it. The treatment cannot restore sight if significant macula damage already exists.

• The medicine: One type of drug injected is known as an ‘antiVEGF’ agent. These drugs reduce the blood leaks from blood vessels which can lead to improved sight. Your eye doctor will discuss your drug options, including their risks and benefits.

• Frequency: Typically, initial injections are given monthly so your eye doctor can review how your eyes respond to the treatment. It’s important to go to every appointment to reduce your risk of further sight loss.

Steroid implants

Some people can use a steroid implant to treat their DMO. These drugs are called Ozurdex® (dexamethasone) or Iluvien® (fluocinolone acetonide). They work for a longer period so you don’t have to return for treatments as often. However, they do come with risks so they might not be suitable for you. Risks include increased eye pressure and the development of cataracts for those who haven’t already had cataract surgery.

Laser treatment

Some people may be offered laser treatment. Laser treatment aims to stabilise vision and does not generally improve sight. It usually involves one or more visits to an outpatient laser clinic for treatment by an ophthalmologist.

Before the procedure, local anaesthetic is administered to the surface of your eye. This numbs your eye so you won’t feel any pain. You are also given eye drops to widen your pupils. A special contact lens is placed on your eye to hold your eyelids open and allow the laser beam to be focused onto your retina. Laser treatment for DMO is not usually painful.

How to reduce your risk of diabetic macular oedema

Diabetes is a lifelong condition, so it's important to maintain a healthy lifestyle.

Help protect your eyesight by:

• Regularly monitoring your blood sugar, blood pressure, and cholesterol levels to keep them within your doctor’s recommended limits.

• Maintaining a healthy weight and blood pressure.

• Eating plenty of fruit and green vegetables.

• Drinking only a moderate amount of alcohol.

• Regularly exercising.

• Not smoking.

• Wearing sunglasses with 100% UV protection.

It is essential to attend your regular diabetes clinic appointments. Your diabetes care team will maintain and monitor your diabetes care plan. Make sure your eyes are screened when you receive an invitation, to spot any problems early.

If you wear glasses or contact lenses, continue to visit your optician regularly and tell the optometrist you are diabetic.

Living with diabetic macular oedema

Loss of central vision through DMO can be very frustrating and can greatly affect everyday life. You can make your remaining vision more comfortable by wearing lenses to block UV and blue light, as well as reduce glare. You can also wear a brimmed hat or visor to shade eyes from direct sunlight.

Even if you are having treatment for DMO, it is important to know what to do if you reach a stage where you begin to struggle with daily tasks. For more information, please see our practical guides, call the Macular Society Helpline on 0300 3030 111 or email help@macularsociety.org 

Research and developments for diabetic macular oedema

The National Institute for Health and Care Excellence (NICE) published the first national guidance on diabetic eye disease in 2024.

This marks a significant step forward in diagnosing and monitoring diabetic eye diseases. The guidance aims to standardise care and improve outcomes for patients across England and Wales.

Macular Society member Berni Warren, who has diabetic retinopathy and maculopathy, was a member of the guideline committee and welcomed the new guidelines.

Support and resources for people with diabetic macular oedema

For more information and support, call the Macular Society Helpline on 0300 3030 111 or email help@macularsociety.org

Join our online DMO support group, so you can:

• Learn more about DMO.

• Connect with others who have DMO.

• Hear from leading clinicians, researchers and sight loss professionals.

• Reduce feelings of isolation.

• Exchange hints and tips about living with DMO.

The group meets once a month on Zoom. There is no need to register in advance, just click the link of the group you’d like to join at the event time and you will be taken straight into the meeting.

FAQs about diabetic macular oedema

What is diabetic macular oedema (DMO)?

Diabetic macular oedema (DMO) is a complication of diabetes and the most common cause of sight loss in people with diabetes.

When leaky vessels cause fluid to build up in the macula, at the centre of the retina, this is known as macular oedema and occurs due to diabetes, inflammation, retinal vein occlusion, surgery, or other reasons. It is painless and affects central vision. Peripheral vision is not affected.

Who is most at risk of DMO?

The longer you have diabetes, the greater your chance of developing sight loss through DMO, which is a complication of diabetic retinopathy. About 90% of people with type 1 diabetes will have some retinopathy after 10 years.

For people with type 2 diabetes the chance of developing some retinopathy after 10 years varies between 67–80% (around 7 to 8 out of 10).

If your blood sugar level is high, you increase the risk of developing retinopathy. 

How will DMO affect me?

In the early stages of diabetes a person may not notice any effect on their vision. Damage to the retina occurs over many years.

However, when blood vessels in or close to the macula become damaged, or there is sudden bleeding or fluid leaking into the macula, sight can worsen dramatically.

You may notice symptoms such as dark spots, faded colours, difficulty adjusting to bright light or glare, trouble reading and objects and lines may appear distorted.

Is DMO curable?

Most early cases of DMO will not require treatment, only monitoring. However, if needed, treatments can stabilise vision and potentially lead to improvements.

What are the treatments for DMO?

Treatments for DMO include laser therapy and injection therapy.

Injections into the eye can stop fluid leaking from blood vessels and laser therapy can potentially stabilise vision.

Can I get a free eye test if I have diabetes?

Yes, if you have diabetes you qualify for free eye tests. Contact your optician for more information and to book an appointment.

What support is available to me?

To learn more about living well with DMO, you can join our online condition-specific support group for people with DMO.

For free, confidential advice and support, call our helpline on 0300 3030 111 or email help@macularsociety.org to find out how we can help.