Retinal screening
Screening for diabetic retinopathy in Grampian is now done by the Grampian Diabetes Retinal Screening Programme. The success of the Retinal Screening Programme depends on referral to the service from primary care of all appropriate patients. All patients are offered appointments at the discretion of their General Practitioner. Patients unable to co-operate with laser treatment or who have no perception of light in either eye should not be offered screening. All other patients should be invited to attend, including those who are registered blind as, despite the terminology, many still have useful remaining vision. In particular the commonest causes of blindness in people with diabetes are age-related macular degeneration and diabetic macular oedema. Screening is still essential to look for new-vessel formation that could affect remaining peripheral vision.
Patients who attend Ophthalmology Clinics for reasons other than diabetic retinopathy should also be encouraged to attend for retinal screening.
More information on retinal screening in left hand column “retinal screening”
This should then be split into the following sections:
Screening criteria
Mydriasis
Medical treatment
Laser treatment
Diabetic eye screening guidelines - classification and action
Fundoscopy
Screening criteria
Who People with diabetes aged 12 years or over
When Refer at diagnosis. Screen at least annually*.
Where Will vary according to local arrangements.
By Whom Routine screening by Diabetes Retinal Screening Programme.
How Digital retinal imaging
*Ophthalmologists or the Retinal Screening Programme may undertake repeat examination more frequently in certain high-risk groups. In pregnancy retinal examination should be undertaken in each trimester.
Defaulters Screen opportunistically by whoever sees them - diabetologist, optometrist, general practitioner.
Should have visual acuity (with glasses or pinhole) recorded and either non-mydriatic retinal photography or direct ophthalmoscopy with mydriasis (1% tropicamide).
Documentation Methodology and findings should be reported according to the Scottish Diabetic Retinopathy Grading System – details in Appendix 5.
Mydriasis
Patients who are attending the Grampian Diabetes Retinal Screening Programme will not routinely have their pupils dilated unless it is not possible to get a gradeable image with digital photography. If dilation is required, 1% Tropicamide should be used. This may cause blurring of vision and affect the ability to drive or operate machinery for up to four hours, and patients should be appropriately warned.
Glaucoma, whatever form, is not a contraindication to mydriasis.
Contact lenses do not need to be removed.
Medical treatment
Tight blood pressure control has a dramatic effect on the progression of eye disease and the prevention of visual impairment. It is always strongly advised. Tight glycaemic control also has a beneficial effect on the progression of eye disease and the prevention of visual impairment. In some patients however if control is tightened up too quickly this can lead to progression of retinopathy. In patients with no retinopathy or only mild background changes this usually manifests itself as the development of cotton wool spots. These are of no consequence and will often disappear. In patients with severe background or worse retinopathy rapid tightening of glycaemic control can lead to rapid progression to high-risk proliferative retinopathy.
· If the patient’s retinopathy status is unknown and they are poorly controlled then they should be referred to the Grampian Diabetes Retinal Screening Programme for assessment prior to tightening up of glycaemic control.
· As it takes years for the complications of diabetes to occur, it would seem prudent for glycaemic control to be improved gradually over 6-12 months in such at risk patients.
· Patients with poorly controlled diabetes who are admitted to hospital with diabetes or non diabetes-related illness should have their eyes examined prior to discharge. This is particularly important if the patient is a chronic defaulter from the Diabetic or Eye Clinic.
Laser treatment
Laser treatment is very effective at treating proliferative (new vessels) retinopathy and will prevent the majority of people developing significant visual impairment.
Laser treatment is less effective at treating patients with maculopathy (changes affect the centre of vision) but attention to blood pressure and glucose control can make a significant impact in preventing deterioration.
Diabetic eye screening guidelines - classification and action
Visual acuity
· Normal corrected visual acuity
Ø Action Review visual acuity annually.
· Visual acuity worse than 6/9 in the worst eye
Ø Stable or previously explained
Action Review visual acuity annually
Ø Deteriorating (by 2 or more lines) or previously unexplained
Action Ask patient to attend their own Optometrist for refraction and if vision cannot be improved then consider reason -
ð Unrelated to diabetic retinopathy (e.g., cataract, chronic amblyopia, senile macular degeneration).
Refer to ophthalmologist as appropriate.
ð Diabetic retinopathy. Macular oedema may present with no specific fundoscopic change.
Refer to ophthalmologist
Fundoscopy
See Appendix 5