What to do... if you have diabetes or diabetic eye disease?

A printable pdf version of the leaflet can be found here.

You are here probably because you are concerned about diabetes and diabetic eye disease. Diabetes is a common cause of retinopathy (pathology affecting the retina). Poorly controlled diabetes can also cause cataracts and neuropathy affecting the cornea. Fortunately, in the majority of patients, vision loss and eye problems are unlikely if the diabetes is well controlled and if the eyes are monitored regularly.

Here are a list of things you can do to protect your eyes if you have diabetes.

Optimise blood sugar and other risk factors

The biggest risk factor for diabetic eye disease, after duration of diabetes, is blood sugar control. Poorly controlled blood sugar level will accelerate the diabetic damage to the eyes, while good control will slow down or stop any damage from occurring. Generally the target blood sugar level should be a HbA₁c of 53mmol/mol.

Other risk factors to pay attention to are:

• blood pressure
• serum cholesterol
• weight

Dr Leo Sheck suggests you to be under a physician specialising in diabetes, such as an endocrinologist, to optimise your diabetes management. This is in additional to your regular GP consultation and blood tests. Continuous glucose monitoring devices (CGM) can be very useful in achieving tight control and limit fluctuation in blood sugar levels. You should discuss the use of CGM with your physician.

Regular and accurate assessment of your retina for diabetic eye disease

Regular diabetic eye examination and imaging are required for all patients with diabetes. This should be commenced when:

• at the time of diagnosis for patients with type II diabetes
• 5 years after diagnosis or at the age of 11 for patients with type I diabetes

Dr Leo Sheck can perform a comprehensive diabetes eye screening for patients with diabetes. This will include a detailed clinical examination, OCT imaging, OCT angiography, and Optos ultra-widefield imaging to ensure the entire retina is evaluated. OCT imaging will detect subtle swelling of the macula not visible on photography or clinical examination alone. OCT angiography is an advanced imaging technique to assess the retinal vessel density, which has additional predictive value on the risk of diabetic retinopathy.

In comparison, the standard diabetes photoscreening involves photography of the mid periphery of the retina only without assessment of the far peripheral retina, and there is no dedicated assessment of the macular thickness (despite macular swelling is a major cause of vision loss in diabetic retinopathy)

For patients with a normal retinal assessment, ongoing assessment can be at every 2 years. More frequent assessments will be required if any pathology is detected, or if a patient is of higher risk of developing diabetic eye disease.

In some patients with diabetic retinopathy, an ultra widefield fluorescein angiogram is required to assess the integrity of blood vessels in the retina to guide treatment.

Preventing vision loss in diabetic retinopathy

Diabetic macular oedema

The macula is the central part of the retina and it is responsible for fine, detailed vision. In diabetes, damage to the vessels can cause leakage of fluid and exudate to the macula, resulting in swelling (which is called diabetic macular oedema). This is a major cause of vision loss in diabetic eye disease.

It is important to detect macular oedema with regular OCT imaging. However, if the macular oedema is mild and the visual acuity good (i.e. better or equal to 6/7.5), no specific eye treatment is required and the oedema can improve with improvement in diabetes control.

Injection treatment for diabetic macular oedema should be commenced if:

• centre involving diabetic macular oedema with acuity worse than 6/7.5
• exudate threatening fovea

The first line treatment for these cases is anti-VEGF injections, i.e. injection of Bevacizumab (Avastin) or Aflibercept (Eylea). These injections are given every 4-6 weeks until the oedema resolves, and can be restarted if the oedema recurs. You can find further information regarding intravitreal injections from a dedicated leaflet on my website (leosheck.com). For patients who failed anti-VEGF injections, injection of a steroid based medication can be performed but this is associated with cataract development and elevated intraocular pressure.

Laser therapy can be performed on patients with diabetic macular oedema that is not involving the fovea. Further information on laser therapy can be found on leosheck.com, under retinal laser.

Proliferative diabetic retinopathy

The diabetic changes in the peripheral retina can be classified as non-proliferative diabetic retinopathy or proliferative diabetic retinopathy. Proliferative diabetic retinopathy means that there is proliferative of abnormal new vessels from the retina to the vitreous, and this is considered high risk for severe vision loss. Proliferative diabetic retinopathy occurs because there is severe closure of the peripheral blood vessels, and the retina is lacking blood supply (i.e. ischaemic).

Laser treatment is required for all patients with proliferative diabetic retinopathy to achieve long term control of the disease. This involves applying laser spots to the peripheral retina, which decreases the oxygen and blood requirement of the retina and in turns induces these abnormal new blood vessels to regress. Usually 2-3 sessions of laser treatment to the eye is required to control the eye disease.

In patients with severe proliferative diabetic retinopathy, or abnormal new vessels not responding to laser treatment, anti-VEGF injections are used to control the disease. However, managing proliferative diabetic retinopathy solely with injection therapy is problematic, as the disease will recur quickly whenever these injections are stopped.

Some patients with proliferative diabetic retinopathy will develop scar tissue on the surface of the retina, and in these cases, a vitrectomy surgery is required to remove the scar tissue. Furthermore, vitrectomy surgery is useful for diabetic patients with non-clearing bleeding into the vitreous.

Optimising cataract surgery in diabetic eye disease

Cataracts are common in patients with diabetes. Cataract surgery will improve vision and also allow better visualisation of the retina for the management of diabetic eye disease.

There are additional risks to consider when performing cataract surgery in patients with diabetes:

• Post-operative macular oedema is much more common in patients with diabetes, and in some cases intravitreal steroid injection is required.
• There can be transient worsening of diabetic retinopathy after cataract surgery.
• Ocular surface discomfort is more common after cataract surgery in patients with diabetes.

Dr Leo Sheck is an expert in both cataract surgery and diabetic retinopathy. He will accurately assess your eyes and devise a plan to minimise these additional risks before your surgery. You can find more information on cataract surgery in the "cataract surgery" leaflet on leosheck.com.

Am i going to go blind?

Most patients with blinding eye disease are those with poor diabetic control who do not regularly attend their eye appointments. With modern assessment and treatment, it is unlikely for patients to lose vision from diabetic eye disease. You can further decrease this risk by following the advice in this leaflet.

If you have any concerns regarding your eyes and diabetes, please make an appointment to see Dr Leo Sheck for a detailed assessment and discussion.

About Dr Leo Sheck

Dr Sheck is a RANZCO-qualified, internationally trained ophthalmologist. He combined his initial training in New Zealand with a two-year advanced fellowship in Moorfield Eye Hospital, London. He also holds a Doctorate in Ocular Genetics from the University of Auckland and a Master of Business Administration from the University of Cambridge. He specialises in medical retina diseases (injection therapy), cataract surgery, ocular genetics, uveitis and electrodiagnostics.