Describe retinal detachment with its types, features and management.

Types and Mechanisms

• The distinction matters absolutely: a rhegmatogenous detachment needs surgery, an exudative detachment needs treatment OF the underlying disease — and operating on an exudative detachment caused by a choroidal melanoma is a catastrophe
• Predisposing factors for rhegmatogenous detachment:

Symptoms and Signs

• 1.
• Flashes (photopsia) — brief arcs of light, worse in the dark and on eye movement, caused by vitreous traction mechanically stimulating the retina.
• They indicate traction and therefore risk → 2.

Treatment

• Prophylaxis — laser retinopexy or cryotherapy around a break that has not yet detached creates a chorioretinal adhesion sealing it. This is a simple outpatient procedure that prevents a major operation, and is the reason symptomatic flashes and floaters must be examined promptly
• Pneumatic retinopexy — an expanding gas bubble is injected, the patient postured so the bubble tamponades the break, and retinopexy applied. Suitable for a single break in the superior retina in a phakic eye; requires a cooperative patient able to posture
• Scleral buckling — a silicone explant is sutured to the sclera to INDENT the wall of the eye inward, bringing the pigment epithelium to the break and relieving vitreous traction, with cryotherapy and drainage of subretinal fluid. It remains an excellent operation, particularly in young phakic patients with an attached vitreous, in whom it avoids causing a cataract. Complications include induced myopia and astigmatism, diplopia, infection and extrusion of the buckle
• Pars plana vitrectomy — the vitreous is removed, traction relieved, subretinal fluid drained internally, endolaser applied and a tamponade placed. It is now the commonest approach, and is necessary where there are multiple or posterior breaks, media opacity, giant tears, or proliferative vitreoretinopathy
• Tamponade agents — gas (SF6 lasting 2 weeks, C3F8 8 weeks), which absorbs spontaneously but requires posturing and an absolute prohibition on air travel and nitrous oxide anaesthesia, either of which causes the bubble to expand catastrophically; and silicone oil, which gives long-term support in complex cases but must be removed and may cause cataract, glaucoma and keratopathy
• Proliferative vitreoretinopathy (PVR) is the principal cause of surgical failure: retinal pigment epithelial and glial cells proliferate on the retinal surfaces and contract, producing fixed folds and a rigid, re-detached retina. It appears at 4 to 8 weeks and requires further, more complex surgery
• Anatomical success exceeds 90% with modern surgery; but visual success depends on whether the macula was detached and for how long — which is why the referral pathway matters more than the surgical technique
• Shafer sign effectively makes the diagnosis of a retinal break in a patient with acute flashes and floaters
• Examine with indentation through a fully dilated pupil; peripheral breaks are invisible any other way