Examining and grading retinopathy, for professionals

June 2008 David Kinshuck

• National Screening Committee    system
• Types of examination
• Links

 

National Screening Committee

The National Screening Committee (NSC) propose the following classification. Some centres use a more detailed classification, based onthe NSC system proposal. The condition is graded by examination of digital retinal photographs.

Abreviations:

• DR = diabetic retinopathy
• NPDR = non-proliferative retinopathy
• NVE = new vessels elsewhere
• IRMAs = intraretinal microvascular abnormalities (part of severe pre-proliferative retinopathy, vessels will not leak with angiogram, otherwise they would be 'new vessels' making the condition 'proliferative')

NSC	International Term	Symptoms	Features (see)	Action
R0	No DR	None	Normal retina.   Grade 0 (US)	annual rescreen
RI	Mild non-proliferative (mild pre-proliferative)	None	Haemorrhages & microaneurysms only only see photo       Grade 1 (US)	Inform diabetes team
R2	Moderate non-proliferative, moderate  pre-proliferative	None	Previously termed mild pre-proliferative. Extensive Microaneurysm, intraretinal haemorrhage, and hard exudates. See photo   and photo     Grade 2 (US)	refer HES
R2	Severe non-proliferative severe pre-proliferative	None	Previously termed severe pre-proliferative. Venous abnormalities, large blot haemorrhages, cotton wool spots (small infarcts), venous beading, venous loop, venous reduplication, IRMA,  See photo and photo . Grade 3 (US)	urgent refer HES
R3	Proliferative retinopathy	Floaters, sudden visual loss	New vessel formation either at the disc (NVD) or elsewhere (NVE). Photos: flat new vessels,    raised,   florid       Grade 4a (US)	urgent refer HES
R3	Pre-retinal fibrosis+/- tractional retinal detachment	Floaters, central loss of vision	Extensive fibrovascular proliferation, retinal detachment, pre-retinal or vitreous haemorrhage, glaucoma.   Grade 4b (US). Traction  photo and photo.   Subhyaloid haemorrhage photo	urgent refer HES
M 0			no maculopathy	annual rescreen
M 1	Diabetic maculopathy	Blurred central vision	The macula is defined as a circle centred on the fovea, with a radius of the distance to the disc margin.  If the leakage involves or is near the fovea the condition is termed clinically significant macular oedema (CSME). Exudative maculopathy presents with leakage , retinal thickening, microaneurysms, hard exudates at the macula. Ischaemic form can have a featureless macular with NVE and poor vision. Photos: moderate,  severe  Milder forms: exudate < or = 1DD of centre of fovea circinate or group of exudates within macula any microaneurysm or haemorrhage < or = 1DD of centre of fovea only is associated with a best VA of < or = 6/12 retinal thickening < or = 1DD of centre of fovea (if stereos available)	refer HES
P	Photocoagulation	Reduced night vision, glare	Small retinal scars through out the peripheral retina. Grade 4b (US)
OL/ UG	Other lesion / Un-gradable		Un-gradable is usually due to cataract, other lesions usually referred for assessment

Clinical Examination

Examination can also be carried out using an ophthalmoscope. This should include use of the green filter (red free) as It shows haemorrhages and new vessels much more easily, see . The slit lamp is very useful clinically.

Links..other grading systems in use

• Some use 7 field photography, useful for research, but totally impractical in clinic
• others use digital photography but the images are processed and graded centrally, again for research programs, and for some screening programs.
• there is no agreement as to which grading system is best; some are appropriate for 'screening ' services, others for the diabetic eye clinic

There are many studies in the academic literature, but few are available in full online. See and here.  Other links available online: photos    medline search (abstracts)     EURODIAB