treatment principles - diabetic retinopathy

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Management of diabetic retinopathy include: primary prevention, regular screening and early detection, and effective treatment of established retinopathy to reduce the risk of visual loss (1).

NICE have issued guidance regarding the management of diabetic retinopathy:

  • eye care for all people with diabetes
    • maintain good blood pressure control (at or below 140/80 mmHg)
    • maintain good blood glucose levels (preferably below HbA1c 6.5-7.5%, according to the individual's target)
    • check visual acuity
    • refer for specialist opinion if cataracts are interfering with vision or the retina is obscured (2)
    • NICE guidance states criteria for timing of review for diabetic eye disease (3)
      • emergency review by an ophthalmologist is indicated for either:
        • sudden loss of vision
        • rubeosis iridis
        • pre-retinal or vitreous haemorrhage
        • retinal detachment
      • rapid review by an ophthalmologist should be arranged for new vessel formation
      • ophthalmologist referral, in accordance with the National Screening Committee criteria and timelines if any of these features is present, is indicated if either:
        • referable maculopathy:
          • exudate or retinal thickening within one disc diameter of the centre of the fovea
          • circinate or group of exudates within the macula (the macula is defined here as a circle centred on the fovea, with a diameter the distance between the temporal border of the optic disc and the fovea)
          • any microaneurysm or haemorrhage within one disc diameter of the centre of the fovea, only if associated with deterioration of best visual activity to 6/12 or worse
        • referable pre-proliferative retinopathy (if cotton wool spots are present, look carefully for the following features, but cotton wool spots themselves do not define pre-proliferative retinopathy):
          • any venous beading
          • any venous loop or reduplication
          • any intraretinal microvascular abnormalities
          • multiple deep, round or blot haemorrhages
        • any unexplained drop in visual acuity.

management of established retinopathy

Majority of patients require controlling of systemic factors to prevent progression of diabetic retinopathy (DR). However, once sight-threatening disease is present, ophthalmic treatment is necessary. Typically this includes:

  • laser photocoagulation
    • peripheral scatter laser treatment is the conventional treatment option for DR
    • it prevents visual loss from proliferative diabetic retinopathy and diabetic maculopathy by inducing regression of the new blood vessels and by reducing central macular thickening
    • when compared with proliferative retinopathy, laser therapy for focal and diffuse maculopathy is not as successful (but still prevents serious sight loss in 60-70% of cases)
    • it is ineffective in ischemic maculopathy
    • given at an outpatient clinic and may involve a single visit or more than one visit before the eye changes are controlled
      • a large number of laser spots (1500-3000 in total) to the peripheral retina are applied during treatment
      • gentle laser burns are applied close to the centre of the fovea in patients with maculopathy, much lower exposure to laser is required than for retinopathy.
    • Driver and Vehicle Licensing Agency (DVLA) should be informed if the patient received laser therapy

  • pharmacological
    • intravitreal steroids
      • injection of corticosteroids such as triamcinolone or fluocinolone directly into the eye has shown to be more effective than laser at the initial stages
        • however by two years, eyes treated with laser had better visual acuity and less macular oedema
      • development of glaucoma and cataract are important side effects
        • there is a development rate for glaucoma of 25-40%, with a peak at 2 months.
    • anti-vascular endothelial growth factor (anti VEGF)
      • vascular endothelial growth factor are raised in the vitreous of eyes with diabetic macular oedema, hence intravitreal injection of anti-VEGF agents (ranibizumab, bevacizumab and aflibercept) have shown to be superior to laser treatment when the vision has been affected
      • results are temporary and require repeated injections at monthly intervals
  • surgical vitrectomy
    • surgical removal of vitreous helps in improving the vision by removing any blood in or behind the vitreous, reattaching detached areas of retina, and reducing the stimulus for neovascularisation by complete pan-retinal laser photocoagulation (4,5,6).

Reference:

Last reviewed 11/2020

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