Screening for diabetic retinopathy is important since the disease is asymptomatic until it progresses to advanced stages (1).
National screening programmes for diabetic retinopathy based on digital retinal photography were developed and implemented in England, Scotland, Wales and Northern Ireland between 2002 and 2007.
- The NHS diabetic eye screening (DES) programme:
- offers annual screening for all people over the age of 12 years with diabetes (type 1 and 2)
- people already under the care of an ophthalmology specialist for the condition are not invited for screening
- offers pregnant women with type 1 or type 2 diabetes additional tests because of the risk of developing retinopathy (1,2).
Screening guidance for diabetic retinopathy has been outlined by NICE (3):
- examine the eyes of people with type 1 and type 2 diabetes at the time of diagnosis and at least annually thereafter (including those registered blind and partially sighted)
- perform an appropriate and acceptable retinopathy screening test
- use tests that have been demonstrated to achieve: sensitivity of 80% or higher; specificity of 95% or higher; and technical failure rate of 5% or lower
- Digital Retinal Imaging, which is currently the most practical method, when conducted and evaluated by trained personnel, or slit-lamp indirect ophthalmoscopy, which is effective in trained hands
- use tropicamide (to achieve mydriasis) unless contraindicated
- opportunistic screening is not an adequate substitute for participation in a formal screening programme. It is an option only if formal screening is not possible.
The guidance states (3):
- visual acuity testing should be performed as a routine part of eye surveillance programmes
- structured eye surveillance should be repeated according to the findings by:
- routine review in 1 year, or
- earlier review, or
- referral to an ophthalmologist
- emergency review by an ophthalmologist is indicated for either:
- sudden unexplained 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
- for more information then visit the NHS screening website
In 2016 the UK National Screening Committee recommended changing the screening interval from every year to every 2 years for people at low risk of sight loss. This was because:
- a large study showed that it was safe to invite people in this low risk group every 2 years rather than annually
- making this change will release capacity in the NHS and lessen the inconvenience for this group of attending appointments every year.
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