Diabetes mellitus causes a characteristic retinopathy. The severity classification according to the International Clinical Diabetic Retinopathy Severity Scale (ICDRSS) places 'Proliferative Diabetic Retinopathy' (PDR) in stage V. The hallmark distinguishing feature from severe NPDR (Stage IV) is:

• A Presence of more than 20 intraretinal haemorrhages in 4 quadrants
• B New vessel formation (neovascularization) on the disc or elsewhere ✓
• C Cotton-wool spots in more than 2 quadrants
• D Clinically significant macular edema with hard exudates

Explanation

PDR is definitively distinguished from severe NPDR by the presence of neovascularization — new vessel formation on or within 1 disc diameter of the optic disc (NVD) or elsewhere on the retina (NVE) or iris/angle (NVI/NVA). Severe NPDR (4-2-1 rule) includes 20+ hemorrhages in 4 quadrants, venous beading in 2+ quadrants, or IRMA in 1+ quadrant, but without neovascularization. Panretinal photocoagulation (PRP) is indicated for high-risk PDR characteristics including NVD ≥1/4-1/3 disc area.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.