Retina and Vitreous
Core concepts
Understand retinal vascular disease: diabetic retinopathy (microaneurysms, dot-blot hemorrhages, hard exudates, neovascularization) and vein occlusion (blood and thunder fundus, sector distribution). Know the stages of diabetic retinopathy and when to treat with panretinal photocoagulation (high-risk proliferative disease) versus antivascular endothelial growth factor for macular edema. Master retinal detachment types: rhegmatogenous (break, subretinal fluid, corrugated retina), tractional (diabetes, no break), and exudative (no break, shifting fluid). Know macular degeneration: dry (drusen, geographic atrophy) versus wet (choroidal neovascularization, treated with anti-VEGF). Know the cherry-red spot in central retinal artery occlusion and the pale retina.
Traps
Questions test that a rhegmatogenous detachment needs surgical repair, not observation, and that a macula-on detachment is an emergency to preserve central vision. Another trap: distinguishing central retinal artery occlusion (pale retina, cherry-red spot, painless sudden loss) from central retinal vein occlusion (blood and thunder, variable loss). Also know that anti-VEGF is first-line for diabetic macular edema, while PRP is for proliferative disease.
Worked example / rule of thumb
A diabetic patient has sudden vision loss with a pale retina and cherry-red spot. That is central retinal artery occlusion, not vein occlusion. Rule of thumb: pale retina with cherry-red spot equals arterial occlusion; blood and thunder equals venous occlusion.