- Intraretinal hemorrhages in 4 quadrants.
- Nerve fiber layer infarcts in 2 or more quadrants.
- Venous beading.
- Intraretinal microvascular abnormalities.
Correct Answer: Nerve fiber layer infarcts in 2 or more quadrants.
The ETDRS (Early Treatment Diabetic Retinopathy Study) established certain findings that can help predict the chances of developing proliferative retinopathy. Of these, intraretinal hemorrhages (or microaneurysms) in 4 quadrants, venous beading in 2 quadrants, and IRMA in one quadrant, are all characteristics. A patient with one of these findings is classified as having severe NPDR and they have a 15% risk of developing PDR over the following year. If two or more are present, they are classified as very severe (45% risk of PDR over the next year). Nerve fiber layer infarcts (and capillary nonperfusion) are both poor prognostic signs, but do not connote a defined risk of developing PDR.