Examining and grading retinopathy, for professionals
June 2008 David Kinshuck
The Diabetic Eye Screening Program propose the following classification. Some centres use a more detailed classification, based on the NSC system proposal. The condition is graded by examination of digital retinal photographs, red free.
- 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')
- dd= disc diameter
- MO= macular oedema
- MA= microaneurysms
|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). Very minor IRMAs||
Inform diabetes team
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)||
|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
|R3s||treated proliferative retinopathy (s = stable)||no haemorrhages or exudates or new vessels, laser ('P' added)||annual rescreen|
|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).
|P||Photocoagulation||Reduced night vision, glare||Small retinal scars through out the peripheral retina. Grade 4b (US)|
|Other lesion / Un-gradable||Un-gradable is usually due to cataract, other lesions usually referred for assessment|
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.
- 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
- needing referral: oedema; exudates within 1 of the fovea
- not needing referral but end up being referred and block up clinics virtual clinics
- exudates outside 1dd of the fovea without oedema
- MA but no MO
- dilemma: need OCT to determine if MO present
- can have an OPDR clinic but quality control not available in hospital clinic; some of these patients attend a virtual clinic (in our clinic we wee such patients, carry out an OCT, if there is no MO discharge back to screening (checking diabetic control is good and if not ask GP to help)
- M1 really needs OCT examination, but this is too expensive as part of the screening program.
- some clnics put M1 patients iinto a virtual clinics, and CTS are read by a nurse.
- severe R2: always need referral, we laser if there are a lot of ischaemic haemorrhages
- very mild IRMAs..probably best considered as part of R1 not needing referral
If mild retinopathy is found, that is retinopathy without needing referral, there is an opportunity to inform the primary care team and get the diabetes under good control. However, this does not seem to be happening efficiently. We can calulate the risk of retinopathy progression www.risk.is.
10% of patients being screened are new patients...new patients are increasing at 5% a year.