Retina and Vitreous
Retina and vitreous is case-based in spirit: you are given a history and a description, and asked for the next step. Recurring themes are diabetic retinopathy, vascular occlusion, macular degeneration, retinal detachment and macular surgery.
Core rules
- Diabetic retinopathy: grade by ETDRS - mild, moderate and severe non-proliferative (4-2-1 rule), then proliferative. Clinically significant macular oedema is thickening within 500 micrometres of the fovea. Anti-VEGF is first line for centre-involving oedema; panretinal photocoagulation for proliferative disease.
- Retinal vein occlusion: superotemporal branch veins are most common. Check blood pressure, glucose and lipids; anti-VEGF for macular oedema; treat glaucoma if present.
- Age-related macular degeneration: dry type with drusen and geographic atrophy; wet type with choroidal neovascular membrane, treated by intravitreal anti-VEGF. Amsler grid monitoring.
- Rhegmatogenous detachment: a tear allows liquefied vitreous into the subretinal space. Symptoms are flashes, floaters and a curtain. Macula-on detachments are repaired urgently; options are scleral buckle, vitrectomy with gas or silicone oil, and pneumatic retinopexy for selected superior tears.
- Macular hole: stages 1 to 4; vitrectomy with internal limiting membrane peel and gas tamponade, with face-down positioning.
- Central serous chorioretinopathy: young to middle-aged men, stress or steroid use, serous neurosensory detachment; observe first.
Worked example
A 58-year-old man reports sudden floaters and a superior visual field defect in the left eye. Funduscopy shows a horseshoe tear at 11 o'clock with fluid tracking toward the fovea, which is still attached. Because the macula is on, you arrange same-day surgery rather than waiting, since a macula-off detachment delays and reduces final acuity. Scleral buckle or vitrectomy both work for a superior tear in a phakic eye.
Traps
Missing a retinal tear in a patient with a normal-looking macula, giving anti-VEGF without checking for neovascular glaucoma, and calling a central serous detachment a choroidal melanoma.