RETINOPATHY 2003 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada

RETINOPATHY  Diabetic retinopathy is the most common cause of new cases of legal blindness in North America in people of working age.  The prevalence rate of proliferative retinopathy is 23% in people with type 1 diabetes and % in people with type 2 diabetes.  Patients with diabetes are also at increased risk of macular edema and cataracts.

SCREENING  The two main approaches to screening are ophthalmoscopy and retinal photography. The gold standard is 7-standard field stereoscopic-colour fundus photography.  Ophthalmoscopy should be carried out by highly trained professionals through dilated pupils.  The performance of mydriatic and nonmydriatic retinal photography depends on a number of factors including the number of photographic fields, resolution of the camera, ability of the professional who takes the images, and the ability of the professional who reads the images.

SCREENING WHEN TO START  At age 15 in type 1 with duration ≥ 5 years  At diagnosis in type 2 HOW  7-field stereo fundus photographs interpreted by a trained reader  Direct ophthalmoscopy or slit-lamp fundoscopy through dilated pupil  Digital fundus photography continued on next slide...

SCREENING...continued from previous slide IF RETINOPATHY IS PRESENT  Diagnose severity and monitor at appropriate intervals (< 1 year)  Treat sight-threatening retinopathy with laser therapy  Review glycemic, blood pressure and lipid control and adjust therapy to reach targets as per guidelines  Screen for diabetes complications IF RETINOPATHY IS ABSENT  Type 1: rescreen annually  Type 2: rescreen in years

PREVENTION  Predictors for the progression of retinopathy include: more severe retinopathy, longer duration of diabetes, higher A1C, higher blood pressure, higher lipid levels and lower hematocrit.  People with type 1 diabetes can delay the onset or slow the progression of retinopathy by improving glycemic control.  People with type 2 treated intensively also show evidence of less retinopathy.  Lowering blood pressure in both types of diabetes can prevent the development and progression of retinopathy.

TREATMENT The following treatments have been shown to be effective for the following conditions:  Cataracts - cataract extraction  Clinically significant macular edema - focal / grid laser photocoagulation  Severe nonproliferative or proliferative retinopathy - scatter laser photocoagulation and vitrectomy  Advanced active proliferative retinopathy unresponsive to laser photocoagulation - early vitrectomy

RETINOPATHY - RECOMMENDATIONS  In people with type 1 diabetes, screening and evaluation for retinopathy by an experienced professional should be performed annually 5 years after the onset of diabetes in individuals  15 years of age [Grade A, Level 1].  In people with type 2 diabetes, screening and evaluation for retinopathy by an experienced professional should be performed at the time of diagnosis [Grade A, Level 1]. The interval for follow-up assessments should be tailored to the severity of the retinopathy. In those with no or minimal retinopathy, the recommended interval is 1 to 2 years [Grade A, Level 1].

RETINOPATHY - RECOMMENDATIONS  Screening for retinopathy should be performed by experienced professionals either in person or through their interpretation of photographs [Grade A, Level 1].  To prevent the onset and delay the progression of diabetic retinopathy, people with diabetes should be treated to achieve optimal control of blood glucose [Grade A, Level 1A], blood pressure [Grade A, Level 1A] and lipids [Grade D, Level 4].

RETINOPATHY - RECOMMENDATIONS  Patients with proliferative or severe nonproliferative retinopathy, vitreous hemorrhage or macular edema should be assessed by an ophthalmologist or retina specialist [Grade D, Consensus] and should be considered for laser therapy and/or vitrectomy [Grade A, Level 1A].  Visually disabled people should be referred for low-vision evaluation and rehabilitation [Grade D, Consensus].