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Diabetic Retinopathy

What is Diabetes, and how can it affect my eye / vision?

Diabetes Mellitus is characterised by elevated blood glucose or blood ‘sugar’ levels (BSLs). The medical term for this is hyperglycemia. A diagnosis of Diabetes Mellitus may often be made, on routine screening tests by a General Practitioner. Currently in Australia, screening for diabetes is recommended every 3 years from the age of 40.

Fundamentally, blood sugar that is higher than normal for a prolonged period of time, causes occlusion of small blood vessels and then complications follow. There is significant risk which can be divided into:

  • Macrovascular (aka large blood vessel) complications; such as heart attack or strokes, or
  • Microvascular (small blood vessel) complications; such as kidney disease, nerve disease (neuropathy) or eye disease (retinopathy).

Unfortunately, severe untreated diabetic eye disease can be blinding and represents a major cause of vision loss. 

Patients with diabetes should have routine eye check-ups, even without visual symptoms as early changes are often ‘silent’ or asymptomatic. Eye checks at least every 1-2 years are recommended for every patient with diabetes. Patients with early changes that are not vision threatening can be reviewed with an optometrist. Patients with more changes, which pose a greater risk to vision,  may need to be seen and examined by an Eye Specialist, or Ophthalmologist. These are medical eye specialists that are able to look at and determine what treatment is required or recommended in order to maintain good vision or prevent vision loss. Some specialists have done further training or ‘Fellowships’ in retinal disease including Diabetic Retinopathy and as such have deeper understanding, training and experience in managing diabetes affecting the eye, termed diabetic retinopathy.

How can Diabetes affect my eye / vision?

Diabetes can affect the eye in several ways, including but not limited to:

  • Dry eye
  • Cataract formation
  • Bleeding within the eye (intraocular / vitreous haemorrhage)
  • Swelling at the macula
  • Glaucoma
  • Retinal blood vessel occlusion (central or branch retinal artery / vein occlusion)
Symptoms

Symptoms that can result from diabetes can include

  • None! Early changes can have no symptoms. It is important to note that even if there are no changes or symptoms affecting the eyes or vision, regular eye checks are required for all patients with diabetes
  • Blurred vision
  • Floaters
  • Flashing lights
  • Eye pain or redness

Because any visual symptoms can have multiple causes, we encourage any patient with diabetes and changes in vision to contact Launceston Eye Institute to arrange a prompt check-up, to determine the cause and course of action.

Diabetic Retinopathy

Blocked small blood vessels cause secondary changes which are visible in the eye during eye checks. This then allows a specialist to determine the severity and hence treatment that may be warranted. Alternatively, observation may be all that is needed, at specific intervals.

Generally, diabetic retinopathy can be divided into; non proliferative or proliferative subtypes.

Non Proliferative Diabetic Retinopathy

Changes seen do not include ‘proliferative changes.’ Visible changes in the blood vessels, along with evidence of minute areas of blood vessel leakage (microaneurysms, dot and blot haemorrhages and exudates) or blockage (cotton wool spots) can be seen through a microscope after dilating drops are applied. However, there are no newly formed abnormal blood vessels present, and as such generally a lower and slower risk of visual deterioration or loss.

Proliferative Diabetic Retinopathy

Changes in the retina display abnormal blood vessel development. This is typically due to chemical release from the body to stimulate new blood vessels to grow, in error, which are generally fragile and prone to bleeding. So patients with newly identified proliferative disease are at risk of intraocular bleeding or ‘Vitreous Haemorrhage.’

Diabetic Macular Oedema

Swelling affecting the central vision due to diabetes is called Diabetic Macular Oedema. It is a common cause of reduced vision in patients with diabetes. This is often detected though special photographs of the retina (called optical coherence tomography or OCT imaging) which are taken in the consultation rooms. These can identify changes that may not be clearly seen with examination alone, and so form a routine part of a diabetic eye check by an eye specialist.

Importantly, Diabetic Macular Oedema, can occur at any severity or stage of diabetic retinopathy.

Treatment of Diabetic Retinopathy

Treatment of eye changes generally is divided into treating either Proliferative diabetic retinopathy, or significant macular oedema. Other changes, generally, are observed.

  • Proliferative diabetic retinopathy is generally treated with laser spots to the edge or ‘peripheral’ retina. This is called ‘panretinal photocoagulation,’ or PRP. This treatment greatly reduces the chance of severe vision loss through intraocular bleeding (vitreous haemorrhage), retinal detachment, or raised pressure in the eye (glaucoma). This is usually delivered in the consulting rooms, over several visits.

 

  • Diabetic macular oedema can be treated with focussed laser treatment or injection therapy. Both can be administered in the consulting rooms. Laser treatment is aimed at ‘spot welding’ the area of leakage with the aim of improving vision. More contemporary treatment however includes intravitreal injections and allow an antidote chemical into the vitreous cavity of the eye, directly to where it is most needed, to prevent swelling and improve vision. Injections are the mainstay of treatment for significant oedema causing vision loss. Typically several monthly injections are initially required in order to dry up the areas of swelling, and because each patient responds in a unique way a customised treatment plan is typically formulated.

 

  • In general, Non proliferative diabetic retinopathy, and the absence of significant macular oedema requires no treatment. However, as for all patients, regular checks are required to identify any changes early and allow best vision and early intervention if things change.

Intraocular bleeding or vitreous haemorrhage if small in amount can settle with time, assuming no further bleeding occurs. Typically if bleeding has occurred, then PRP laser treatment is required. If there is large, recurrent bleeding causing significant reduction in vision then surgery may be undertaken to remove the blood, clear the vision and allow laser treatment to prevent further bleeding episodes.

What can I do to help my eyes and vision?

We encourage all patients to be invested in their own eye health. This includes 

  • Regular eye checks at recommended intervals
  • Seeking timely review if there are changes in vision
  • Good blood sugar, blood pressure and blood lipid / cholesterol management, which allows best possible blood vessel health

In fact, the risk of diabetic retinopathy worsening can be significantly reduced with optimal blood sugar, blood pressure and cholesterol management. As such, regular and close collaboration between the partnership formed by the patient, patient’s General Practitioner or Diabetic Specialist and the Eye Specialist provide the foundation and support network for optimal eye care.

Important Notes
  • Every patient with diabetes needs regular eye checks, even if vision is good and there are no symptoms
  • There are several reasons for vision changes if you have diabetes, so prompt review offers the best options for early treatment 
  • Treatment for each patient includes eye treatment, but also optimisation of blood sugar, blood pressure and cholesterol and lipids with a GP or specialist 
  • Further information is available at https://www.healthdirect.gov.au/diabetic-retinopathy.
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