General practice management of type 2 diabetes

Other ophthalmological effects
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Refractive errors

Refractive errors occur as the lens’ shape alters with changes in blood glucose concentrations and result in blurred vision. Detection is done with pinhole test – blurred vision due purely to refractive error corrects with the pinhole test.

Correction of refractive errors should be postponed until blood glucose levels are stabilised.


Cataracts occur prematurely in people with diabetes. Patients present with blurred vision and glare intolerance, and may find night vision a particular problem.

Over time, interpretation of colours becomes more difficult.

Clinically, the light reflex is reduced and fundus may be difficult to see.

Surgical treatment is recommended when reduced acuity is affecting lifestyle and independence.


Maculopathy is difficult to see ophthalmoscopically, but is the most common cause of visual loss in people with diabetes. Assessment is by direct ophthalmoscopy (with dilated pupils), retinal photography and fluorescein angiography, depending on the state of the patient’s fundi.

Intra-vitreous injectable ranibizumab and aflibercept have recently been approved under the PBS as monotherapy or in combination with laser photocoagulation for diabetic macular oedema under management by an ophthalmologist. Refer to the PBS for further information.

Sudden blindness

Sudden loss of vision is an emergency and may be due to:

  • central retinal artery occlusion
  • retinal detachment
  • vitreous haemorrhage.

These conditions can occur independently of diabetes. Urgent contact with an ophthalmologist or timely assessment by a specialist team is indicated.

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