Retina and Vitreous
This section covers retina and vitreous: diabetic retinopathy, macular degeneration, retinal detachment, vascular occlusion, and macular oedema. The exam tests staging, imaging, and time-critical treatment.
Core rules and concepts
- Diabetic retinopathy is staged as non-proliferative or proliferative; macular oedema can occur at any stage and is treated with anti-VEGF injections.
- Proliferative disease needs panretinal photocoagulation; vitrectomy is used for non-clearing vitreous haemorrhage or tractional detachment.
- Age-related macular degeneration is dry or neovascular; neovascular AMD shows subretinal fluid, haemorrhage, and choroidal neovascular membrane on OCT or angiography.
- Rhegmatogenous retinal detachment presents with flashes, floaters, and a visual field defect; it is repaired urgently with laser, pneumatic retinopexy, or vitrectomy.
- Central retinal artery occlusion causes sudden painless monocular loss with a cherry-red spot; giant cell arteritis must be excluded in older patients.
Worked example
A 68-year-old has sudden painless loss of vision in one eye. Fundoscopy shows a pale retina with a cherry-red spot at the macula. The diagnosis is central retinal artery occlusion. Check ESR and CRP urgently to exclude giant cell arteritis, especially with jaw claudication or scalp tenderness. There is no proven benefit from routine reperfusion, but stroke risk factors are managed. If arteritic disease is suspected, high-dose systemic steroid is started immediately to protect the fellow eye.
Traps that cost marks
Do not miss a retinal detachment in a patient with dense vitreous haemorrhage; ultrasound is useful. Anti-VEGF requires monitoring for endophthalmitis and IOP rise. A cherry-red spot is not specific to CRAO. In diabetic patients, always examine the fellow eye and look for neovascularisation at the disc or elsewhere.