## Distinguishing DME from Vitreous Hemorrhage **Key Point:** DME is characterized by **accumulation of fluid in the macula** (intraretinal or subretinal), best visualized on OCT as central macular thickening (>250 µm). Vitreous hemorrhage is blood in the vitreous cavity that obscures the fundal view. ### Pathophysiology and Imaging Distinction | Feature | DME | Vitreous Hemorrhage | |---------|-----|---------------------| | **Primary pathology** | Fluid accumulation in macula | Blood in vitreous cavity | | **OCT findings** | Intraretinal/subretinal fluid, CMT >250 µm | Vitreous opacification; macula may be obscured | | **Fundoscopy** | Hard exudates, retinal thickening, may see macula | Hemorrhages obscure view; vitreous appears hazy/dark | | **Best discriminator** | OCT showing macular edema | Vitreous opacity on indirect ophthalmoscopy | | **Visual acuity** | Reduced due to macular involvement | Reduced due to media opacity | ### Why OCT is the Gold Standard OCT provides **cross-sectional imaging** of the retina and reveals: - Intraretinal cystic spaces (fluid pockets) - Subretinal fluid accumulation - Central macular thickness measurement - Disruption of the normal foveal architecture These findings are **pathognomonic for DME** and cannot be seen with vitreous hemorrhage alone. **Clinical Pearl:** In a patient with vitreous hemorrhage obscuring the macula, OCT can still visualize the macula beneath the hemorrhage and detect concurrent DME. This is crucial for treatment planning. **High-Yield:** NEET PG frequently tests the distinction between DME (fluid in retina) and vitreous hemorrhage (blood in vitreous). OCT showing macular thickening with fluid is the definitive discriminator. **Mnemonic:** **DME = Edema (fluid on OCT); VH = Haze (blood obscures view)** [cite:Kanski Clinical Ophthalmology Ch 12; American Academy of Ophthalmology Preferred Practice Pattern: Diabetic Retinopathy] 
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