Diabetic eye disease - screening and treatment options

Diabetes is responsible for various degrees of eye disease, known as diabetic retinopathy. This article discusses  treatment options for diabetic retinopathy and also ways of preventing the condition.


There is a worldwide increase in diabetes and related health problems. Diabetes is a disease where blood sugar levels are affected either because of the lack of a hormone named insulin or because of a reduced response to insulin. This causes abnormally high blood sugar levels after eating. Over time this can lead to damage in many organs of the body. It can cause kidney failure, heart disease, nerve damage, stroke and blindness. This article will explain what the most common diabetic eye problems are, how they present, how they can be screened for and what the treatment options are.

How does diabetes affect the eyes?

Diabetes can lead to damage in the eye called Diabetic Retinopathy. The retina is your ‘seeing’ part in the back of the eye. High blood sugar levels cause damage to your retinal blood vessels, which in turn causes bleeding, and leakage of exudates in your retina and, in advanced disease, this leads to the formation of abnormal new blood vessels. High blood pressure and high blood fat increase the damage on your retina. Diabetic retinopathy is the most common cause of blindness in the working population in the western world.

Symptoms of diabetic retinopathy

Fluctuating or changing vision

This is often one of the first symptoms of diabetes and although it can be very annoying, it is not dangerous to your eyesight. It is caused when the high blood sugar levels lead to a swelling of the natural lens in the eye, which then results in a change of focus or refractive power of the eye. A change in the refractive power feels like you need new glasses but as soon as your blood sugar levels go back to normal your focus changes again and you will find that you can see with your old glasses.

Diabetic retinopathy: Diabetes can damage your retina and can lead to a reduction or loss of your sight in two ways:

Diabetic maculopathy

Diabetic maculopathy is caused by leakage and bleeding of damaged blood vessels in the centre of your retina, named the macula. A swelling in the centre of your macula is named Cystoid Macular Oedema (CMO). This process generally happens over a period of months.

Proliferative Diabetic Retinopathy

In more advanced diabetic eye disease the blood vessels are damaged and are unable to supply the required amount of oxygen to the retina. This leads to the growth of new abnormal blood vessels named Proliferative Diabetic Retinopathy, these cause a multitude of eye problems all leading to reduced vision or loss of sight. The growth of these blood vessels can cause severe bleeding in the eye, increased pressure in the eye with damage to the optic nerve and detachment of the nerve fibre layer (retina detachment).

Diabetic eye checks

Regular screening for diabetic eye disease is most important in order to act early on a potentially blinding disease. In the UK, all patients over the age of 12 are offered a yearly screening visit to check if they have any treatable Diabetic Retinopathy or Maculopathy. The screening is done by digital photography of your eyes. You should try to attend the screening programme but if you decide not to attend, you should see an ophthalmologist privately and ask to have the results sent to your local screening programme.

How can I prevent diabetic eye disease?

The better your diabetic control including maintenance of good blood pressure and cholesterol levels, the less likely you are to develop diabetic retinopathy. The good news is that even if you have developed some diabetic retinopathy you can reverse some or all symptoms by improving your control of the above.

When do I need treatment?

There are two main conditions which will need treatment:

  • When you have Maculopathy (CMO) which has led to a swelling in your central area and is causing, or threatening to cause, a decrease in your vision.
  • When you have Proliferative Diabetic Retinopathy which is caused by the development of new faulty blood vessels on your retina.

What treatment is available?

Laser treatment

This is the standard treatment for diabetic retinopathy and has the longest track record and is still the most applied treatment.

For Maculopathy (CMO): Focal laser and /or a grid type laser are applied to the centre of the retina to decrease the thickening. Anything between 1–150 laser shots are applied in one visit.

For Proliferative Diabetic Retinopathy: Peripheral laser treatment is applied to the retina to reduce and eliminate the newly developed blood vessels. The laser destroys some of the outer part of the retina leading to a decreased need for oxygen in the eye and resolving the problem of the new blood vessels. 1200–2000 laser shots are applied, in one or more sessions.

Anti-VEGF intravitreal injections

For Maculopathy (CMO): In January 2011 Ranibizumab was approved by the European Medicines Agency for the use in CMO. Ranibizumab blocks a growth factor protein in the eye and stops blood vessels leaking and new blood vessels from growing, although only temporarily. This treatment is not yet available on the NHS for diabetic macular oedema. In the first year you will need up to ten injections with considerably less in the second and third year.

For Proliferative Diabetic Retinopathy: Ranibizumab injections lead to temporary closure of the new blood vessels caused by Proliferative Diabetic Retinopathy. The brand named drug, Lucentis, is not yet licensed for this treatment but is used a an ‘off label’ treatment.


An operation where the gel in the eye (vitreous) is removed by a cutting device.

If there is bleeding in the eye caused by new blood vessels in Proliferative Diabetic Retinopathy and the bleeding does not clear, the blood can be removed by this operation, laser treatment and sometimes injection of Anti-VEGF drugs are given at the same time.

In some cases of macular oedema where the swelling is mainly caused by the pull of a fine membrane, macular traction, and not only by leaking blood vessels, a Vitrectomy can peel the membrane and help to maintain or restore sight.

What does the treatment involve?


Treatment is done during an outpatient visit; you sit in front of the laser during the procedure and a small contact lens is placed in your eye. The treatment is generally not painful and you can go home directly after. You don’t need any medication after treatment.

Anti-VEGF injections

The treatment is done during an outpatient visit, in a special clean room where you get some eye drops to numb and disinfect the eye. The injection is given with a very fine needle and you should not feel any pain. You can go home directly after the treatment and need to administer some antibiotic eye drops for three days.


For this treatment you need to be admitted for Day Surgery, most of the time the operation is performed under local anaesthetic but sometimes the surgeon may suggest a general anaesthetic, where you are put to sleep. After a short recovery period you are allowed to go home on the same day. You are given one or several eye drops to administer at home.

Other common eye problems related to diabetes

Dry Eyes

  • Symptoms of irritation, intermittent blurred vision which is improved by blinking, as well as watery eyes caused by reflex watery tears. The cause is an unstable tear film.
  • The treatment is a simple replacement of the inefficient tears with artificial tear drops.


  • Cataracts are caused by the clouding of the natural lens and are part of the normal aging process. In diabetic patients cataracts can develop earlier due to the high blood sugar levels affecting the lens.
  • The treatment is a cataract operation where the lens is removed and replaced by an artificial plastic lens.

Summary of latest treatment options

  • Anti-VEGF treatment in diabetic macular oedema.
  • Anti-VEGF treatment in Proliferative Diabetic Retinopathy. This is still an off label treatment.
  • Vitrectomy in patients with macular traction.
  • Vitrectomy in patients with severe bleeding in the eye.

Details of treatment approach

  • Improve control through work with diabetic nurse and/or diabetologist.
    • Check and control blood pressure, blood sugar and cholesterol.
  • Laser in localised CMO and new blood vessels due to Proliferative Diabetic Retinopathy.
  • Anti-VEGF injections in patients with diffuse or cystoid Macular Oedema.
  • Referral for Vitrectomy in patients with oedema caused by macular traction and for patients with non-clearing blood in Proliferative Diabetic Retinopathy.

Pros and Cons having treatment for diabetic retinopathy

Pro Laser Treatment

In diabetic macular oedema and in Proliferative Diabetic Retinopathy, large studies have shown the long-term benefit of laser treatment compared to no treatment.

Con Laser Treatment

Side effects including reduction of vision, increase in macular oedema, bleeding and a reduced visual field meaning patients are no longer allowed to drive.

Pro Anti-VEGF Injections

In diabetic macular oedema Ranibizumab was found to be more effective at improving vision than laser treatment alone.

Con Anti-VEGF Injection

Side effects of the treatment are increased pressure in the eye, inflammation in the eye, bleeding, eye pain, floaters, retinal detachment, and very rarely endophthalmitis (an infection inside the eye).

Pro Vitrectomy

Vitrectomy is beneficial in severe bleedings (vitreous haemorrhages) caused by new blood vessels, especially in younger diabetic patients and seems to be beneficial in macular oedema with traction. However vitrectomy is not a first line treatment and is reserved for special indications.

Con Vitrectomy

Side effects of the treatment include increased pressure in the eye, inflammation in the eye, bleeding, eye pain, floaters, retinal detachment and very rarely, endophthalmitis.

What is the post-operative treatment and follow-up rate?

Laser Treatment

No post-operative treatment; the follow-up rate is between three and six months, depending on the type of laser treatment.

Anti-VEGF injections

Post-operative treatment is antibiotic eye drops for three days; the follow-up rate is monthly.


Post-operative treatment includes antibiotic eye drops, anti-inflammatory eye drops and sometimes pressure-reducing eye drops; the follow-up rate is first daily and then weekly to monthly for a few months.

Sources and websites for further information

Diabetes UK
English National Diabetic Screening Programme
Royal College of Ophthalmologists
European Medicines Agency
Diabetic Retinopathy Clinical Research Network

For further information on the author of this article, Consultant Ophthalmologist, Miss Susanne Althauser, please click here.
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Swelling to the central part of the retina (macula) Full medical glossary
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