Retina and Vitreous
Core concepts
Separate retinal disease by layer and mechanism: vascular (diabetic retinopathy, vein occlusion), degenerative (AMD, dystrophies), tractional (vitreomacular, proliferative diabetic), and detachment (rhegmatogenous vs tractional vs exudative). Know the diabetic retinopathy staging (NPDR severity, PDR with high-risk features) and the role of anti-VEGF and panretinal photocoagulation.
Understand retinal detachment: a tear allows fluid into the subretinal space, causing a symptomatic detachment with a corrugated, mobile retina and a visible break. Tractional detachment is concave, immobile, and often in proliferative disease. Exudative detachment shifts with posture.
Traps
- Missing a retinal tear in a patient with flashes and floaters (dilated exam is essential).
- Confusing central serous chorioretinopathy with wet AMD in a young patient.
- Overlooking macular oedema as a cause of vision loss in diabetes.
- Assuming a retinal detachment is rhegmatogenous without finding a break.
Rule of thumb
Flashes + floaters = dilated fundus exam to look for a tear; and a detachment with no break should prompt a search for tractional or exudative causes.
Worked example
A 58-year-old with sudden painless visual loss, a curtain, and a superior visual field defect. Dilated exam shows a mobile, corrugated inferior detachment with a superior temporal horseshoe tear. This is rhegmatogenous; urgent repair (pneumatic retinopexy or scleral buckle/vitrectomy) is indicated.