Macular Oedema: Causes, Symptoms and Treatment

Macular oedema is the most common cause of sight loss in patients with diabetes. Oedema means fluid retention or swelling. Symptoms include mild to severe loss of central vision.

Being diagnosed with diabetic macular oedema (DMO) can be worrying, but the condition can be treated and effectively managed. From eye drops to intravitreal injections and surgery, there are many options available. And with the right information, patients can cope very well and make informed decisions.

What Is Macular Oedema?

The retina is the nerve lining at the back of the eye. It contains special cells (photoreceptors) sensitive to light that send signals to the brain, which interprets them as images.

The macula is the central part of the retina that provides clear, sharp vision. It is about 5mm across, and it has a high density of photoreceptors, especially at the center (known as the fovea). This area is responsible for your central vision and the fine details of what we see (visual acuity).

Macular oedema is an eye disease that happens when leaky vessels cause fluid to build up in the macula. As this is a highly sensitive and vital area of the eye, when the damaged retinal blood vessels allow this accumulation of fluid, it is waterlogged and unable to function. Hence, you get blurred and distorted vision.

Edema is usually described as two types, depending on the underlying cause and associated structural changes.

  • Cystoid macular oedema (CMO). Fluid accumulation in cyst-like (honeycomb) spaces in the outer layer of the macula. This condition is the endpoint of many intraocular conditions.
  • Diabetic macular oedema (DMO). High blood sugar levels weaken blood vessels causing them to leak into the macula. DMO may lead to CMO.

Two mechanisms can cause cystoid macular oedema: vitreous traction and inflammation. If vitreous traction is present, the vitreous (gel that fills the eye) pulls on the macula, causing the cystoid macular edema. On the other hand, inflammation is the most common mechanism behind cystoid macular oedema.

What are the Causes of Macular Oedema?

Macular oedema is not a disease itself. It is more a result of other diseases and medical conditions. Among the many causes, diabetes stands out in first place. Diabetic macular oedema is a complication of diabetic retinopathy.

Also, eye surgery could increase the risk of developing this disease due to irritation of the blood vessels, allowing fluid to leak out.

It can also develop after cataract surgery, called pseudophakic cystic macular oedema (PCME). Hence, cataract surgery in patients with diabetes, already at risk, may result in the dramatic acceleration of pre-existing diabetic macular oedema.

Other causes include:

  • Ocular inflammatory diseases (uveitis).
  • Retinal vascular disease (retinal vein occlusion).
  • Macular degeneration, a common cause of vision problems as we get older. It comes in two forms – wet and dry.
  • Drug-induced changes (topical adrenaline).
  • Hereditary/genetic conditions, such as retinitis pigmentosa.

What are macular oedema symptoms and diagnosis?

The symptoms of macular oedema can vary depending on how swollen the macula is and whether it affects one or both eyes. If the cystoid macular edema is mild, there may be no symptoms at all. When symptomatic, the condition is painless. The main feature is blurry vision.

Macular edema only affects central vision, so peripheral vision remains untouched. So, your vision can get really bad, but you won’t go completely blind. You would be able to catch sight of objects “out of the corner of your eye.”

Black spots like a smudge on glasses or gaps may appear in your vision, especially when you wake up in the morning. Also, colors can seem washed out and fade (color desaturation). You may experience difficulty reading and recognizing faces. Also, straight lines and letters may seem distorted or bent (metamorphopsia).

Aside from symptoms and medical history, your eye doctor will perform a slit lamp examination to confirm the diagnosis. He/she will dilate your pupils and use a magnifying lens to examine the back of your eye more closely.

Sometimes, it is necessary to use additional imaging tests, though. Indeed, the diagnosis is often confirmed after Optical Coherence Tomography (OCT), a sort of visual biopsy that allows objective measurement of retina volume and thickness changes. OCT scans provide a cross-sectional image of the retina, useful for diagnosis and monitoring progress after treatment.

Fluorescein angiography could also be required to refine the diagnosis and guide management. A dye is injected into a vein in your arm. It travels right to the eye, highlighting the blood vessels in the retina so that the eye doctor can identify the precise points of leakage.

What are the Treatment Options for Macular Oedema?

Treatments of macular oedema will depend on the cause and the degree of progression. This eye disease is usually self-limited and can resolve spontaneously within 3-4 months. However, healing may be helped with medical or surgical options.

If the oedema is chronic (more than nine months), you could end up with permanent damage due to retinal fibrosis.

So, macular oedema can be treated if caught early. The key is to find out the cause behind the blood vessels leakage (diabetes, post-surgical inflammation, vascular disease) and then address the swelling in the macula.

Possible treatments include eye drops, tablets, intravenous or intraocular injections of NSAIDs (indomethacin and ketorolac), steroids or anti-VEGF medication.

Your eye doctor will take a step-by-step approach, starting with topical treatment and moving up to intraocular injections. They all aim at sealing fluid leaks from the macula by suppressing inflammation.

Other options include laser therapy and vitrectomy surgery.


Intravitreal injections are an outpatient procedure performed in the doctor`s office. The eye is anaesthetized using special eye drops, and the needle goes into the corner of the eye. The drug used (anti-VEGF or steroid) depends on the underlying cause (diabetic eye disease, postoperative macular oedema, retinal vein occlusion, or macular degeneration).

There are currently two drugs in use for treating DMO: Lucentis® (ranibizumab) and Eylea® (aflibercept). They have become the standard of care for patients with macular oedema, replacing photocoagulation laser treatments.

Anti VEGF stands for “anti-vascular endothelial growth factor.” Essentially, anti-VEGF drugs reduce new blood vessel growth. Also, they act on the blood vessels in the retina to prevent fluid leakage that leads to oedema in the eye.

The number of injections and dosage depends on how a patient responds to the treatment. Generally, patients receive four injections, each spaced one month apart, as a “loading dose.”

Patients with a chronic disease that haven’t responded to standard treatment with anti-VEGF injections, or eyes that are not suitable for anti-VEGF therapy in the first place, may give steroid injections a try.

Iluvien (Fluocinolone acetonide) and Ozurdex (Dexamethasone) are the approved steroids for intravitreal injections. Both these drugs come as a steroid-releasing implant (Iluvien) or a dissolving steroid pellet into the eye, which slowly release the drug over 3-6 months (Ozurdex) or up to 3 years (Iluvien).

Side effects of steroid injection include infection (low risk), increased ocular pressure with glaucoma (33%), and cataract formation (85%).

Whichever medication you receive, expect your vision to be slightly blurred for a few hours after the procedure. The dilating drops have to wear off first. Also, your eye will be irritated or watery after the injection and may be slightly bloodshot.


Laser photocoagulation uses a focused laser beam on your eye to seal leaking blood vessels. When the DMO does not involve the center of the macula, laser treatment can be an option. This treatment aims to stabilize vision and does not generally improve sight.

You may need more than one laser treatment session to control the condition, though.

Before the procedure, your doctor will apply local anaesthetic, and special eye drops to widen your pupils. Then, a special contact lens will be placed on your eye to hold your eyelids open. This will allow the laser beam to be focused onto your retina more easily.

Laser treatment is not a painful procedure, but you may experience a sharp prickling feeling.


Surgery called vitrectomy can help to relieve macula oedema refractory to medical therapy. It is considered when the cause of macular oedema is vitreous tugging/traction. So, a vitrectomy is performed to remove the vitreous gel (the underlying cause).

As with medical treatment, some patients respond very well to the surgery and recover good vision, while others experience little or no improvement.

Side-effects of vitrectomy include cataracts, retinal detachment, vitreous haemorrhage, and increased intraocular pressure.


With new treatment options available, such as intravitreal injections with anti-VEGF drugs, the main goal has changed from slowing or reducing visual loss to partial improvement if possible. However, your doctor can’t predict how long it may take for macular oedema to respond to treatment.

Most cases may resolve within several weeks to a few months. However, some patients require long-term treatment.

Cystoid macular edema after cataract surgery generally has excellent recovery, with most cases responding to medical treatment. Once macular oedema resolves, the vision acuity typically returns back to normal. However, chronic and severe macular edema, can lead to permanent vision loss despite treatment.


Pre-operative NSAIDs are prescribed to high-risk patients in cataract surgery. Indeed, diabetic patients need intensive steroid cover for cataract surgery to minimize the risk of deterioration.

Also, when trying to prevent macular oedema, catching on time the underlying cause could be effective.

Considering that more than 30% of all diabetic patients will develop macular edema, having a good glycaemic, blood pressure, and cholesterol control may stall the development of retinopathy. So, small changes in your levels can significantly affect your risk of developing retinopathy and diabetic macular oedema.

Once it is present, the progression of the condition can be slowed down with laser and other treatment modalities. Also, regular retinal examinations will help detect changes early and start treatment before vision deteriorates.


Macular oedema treatment cost depends on the technique performed. If you want to receive a quote, please, fill in the contact form. You can send us your recent medical reports, so we can offer you the solution that best suits your needs.

You can be sure that this information will always be treated with maximum confidentiality.


Doctor Mª José Capella Elizalde

Doctor Mª José Capella Elizalde

Graduated in Medicine (Universidad Autónoma de Barcelona, 2005). Specialization in Ophthalmology at the Barraquer Ophthalmology Centre (2006-2010). Training in the subspecialty of Uveitis and Ocular Inflammation in USA centers such as the Massachusetts Eye Research and Surgery Institution and the Bascom Palmer Eye Institute (2011). Member of the Department of Vitreous-Retina and Uveitis and Ocular Inflammation Unit at the Barraquer Ophthalmology Centre. Member of the faculty of the Graduate Program of the Universidad Autónoma de Barcelona, given by the Institut Universitari Barraquer (Master Program and Intensive Courses).
Languages: Spanish, Catalan, English, French
Association number: 40.718

Doctor Javier Elizalde

Doctor Javier Elizalde

Bachelor in Medicine and Surgery (Universidad Autónoma de Barcelona, 1990). Doctor Cum Laude in Medicine and Surgery (UAB, 2003) with National Prize Thesis. Training of specialist in ophthalmology in the MIR Barraquer Ophthalmology Centre (1991-1994). Chief of residents in 1994. Training in USA in pathology and surgery of the vitreous and retina at the Bascom Palmer Eye Institute (Miami, 1995-1998) with Dr. Donald Gass, in Columbia University (New York) with Dr. Stanley Chang, at the Vitreous Retina Macula Consultants (New York) with Dr. Lawrence Yannuzzi and in Memphis (Tennessee) with Dr. Steve Charles. Complementary Training in ocular oncology at the Wills Eye Hospital (Philadelphia) with the Drs. Jerry and Carol Shields (1999). Deputy Coordinator of the Vitreous-Retina Department. Coordinator of the Ocular Oncology Unit. Vice-president of the Academic Board of the Barraquer Institute.
Languages: Spanish, Catalan, English, French, Italian
Association number: 27.498

Doctor Sònia Viver

Doctor Sònia Viver

Bachelor of Medicine and Surgery (2001) and specialist in Ophthalmology (2006). She works at the Vitreous-Retina Department of the Barraquer Ophthalmology Centre, highlighting her work in the field of diagnosis, treatment and monitoring of Age-Related Macular Degeneration. Member of the teaching staff of the Master, Diploma courses and other Postgraduate courses organized by the Institut Universitari Barraquer (UAB).
Languages: Spanish, Catalan, English

Doctor Santiago Abengoechea

Doctor Santiago Abengoechea

Bachelor of Medicine and Surgery (University of Barcelona, 1996). Specialized in Ophthalmology (2001). Stay in the “Bascom Palmer Eye Institute” Miami (USA, 2007) with Dr. Philip Rosenfeld. Coordinator of the treatments of Age-Related Macular Degeneration (AMD) and the Optical Coherence Tomography Department.
Languages:  Spanish, Catalan, English.
Association number: 32.305


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    External links – Bibliography

    Macular edema is a rare finding in untreated vitreoretinal lymphoma: small case series and review of the literature. Carreras E, Salomão DR, Nadal J, Amin SR, Raja H, Grube TJ, Geraets RL, Johnston PB, O’Neill BP, Pulido JS.Int J Retina Vitreous. 2017 Apr

    Vitreomacular traction syndrome. Bottós J, Elizalde J, Arevalo JF, Rodrigues EB, Maia M.J Ophthalmic Vis Res. 2012 Apr;7(2):148-61.

    Classifications of vitreomacular traction syndrome: diameter vs morphology. Bottós J, Elizalde J, Rodrigues EB, Farah M, Maia M.Eye (Lond). 2014 Sep;

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