Retinal Detachment

Retinal detachment is separation of the neurosensory retina from the retinal pigment epithelium by subretinal fluid. Untreated, it leads to permanent photoreceptor loss and blindness. Incidence is about 10 to 20 per 100,000 per year, with a lifetime risk of roughly 1 in 300.

Types

• Rhegmatogenous (about 95%): a full-thickness retinal break allows liquefied vitreous to enter the subretinal space. Posterior vitreous detachment is the usual precipitant, with traction on the retina causing horseshoe tears, round holes, or atrophic holes and dialyses.
• Tractional: fibrovascular proliferation contracts and pulls the retina from the pigment epithelium, as in proliferative diabetic retinopathy, retinopathy of prematurity, sickle cell retinopathy, and trauma.
• Exudative: subretinal fluid accumulates without a break, from inflammation, tumours, central serous chorioretinopathy, Vogt-Koyanagi-Harada disease, posterior scleritis, uveal effusion syndrome, severe hypertension, pre-eclampsia, and Coats disease.

Risk factors

• High myopia.
• Previous cataract surgery and YAG capsulotomy.
• Lattice degeneration, previous retinal detachment in the fellow eye, family history, Stickler syndrome and Marfan syndrome.
• Ocular trauma, and age 50 to 70 years with posterior vitreous detachment.

Complications include proliferative vitreoretinopathy, macular involvement and permanent visual loss. Prognosis depends on macular status and duration.

Prodromal symptoms of posterior vitreous detachment and tears include sudden onset of floaters and flashes of light, often in a patient over 50 years or with high myopia.

Detachment symptoms

• A shadow or curtain spreading across the visual field, progressing from the periphery.
• Central vision loss and distortion when the macula detaches.
• The process is typically painless.

Signs

• Reduced vision when the macula is involved, or preserved central acuity when it is not.
• Relative afferent pupillary defect in extensive detachment.
• Lower intraocular pressure than the fellow eye.
• Shafer sign, with pigment cells in the anterior vitreous, indicating a retinal break.
• Fundus examination may show a grey, elevated, corrugated and mobile retina with a visible retinal break.
• Proliferative vitreoretinopathy produces stiff folds and a fixed retina.
• Tractional detachments are concave and immobile.
• Exudative detachments have shifting fluid and no retinal break.

Differential diagnosis includes posterior vitreous detachment without tear, vitreous haemorrhage, retinoschisis, choroidal detachment, macular degeneration, migraine aura, retinal vascular occlusion, optic neuritis and ocular melanoma.

Same-day ophthalmology review is required for new floaters with photopsia, any field defect, vitreous haemorrhage or ocular trauma.

Dilated fundus examination by an ophthalmologist is the principal test.

Examination method

• Dilate with tropicamide 1% and phenylephrine 2.5% after documenting visual acuity, pupils and intraocular pressure.
• Binocular indirect ophthalmoscopy with scleral depression to examine the periphery to the ora serrata, and slit-lamp biomicroscopy with a fundus contact lens or 90 dioptre lens.
• Examine both eyes, since bilateral breaks occur in about 10%.
• Draw the detachment and mark all breaks.

Adjunct tests

• B-scan ultrasound when the fundus view is blocked by vitreous haemorrhage, cataract or corneal opacity. It distinguishes retinal detachment from posterior vitreous detachment and choroidal detachment.
• Optical coherence tomography for macular status, subretinal fluid, epiretinal membrane and macular hole.
• Wide-field fundus photography and fundus autofluorescence for documentation and monitoring.
• Fluorescein angiography, CT or MRI, and ultrasound for exudative causes and masses.
• Visual fields when indicated.

Before anaesthesia, assess medical history, anticoagulant and antiplatelet use, diabetes control, blood pressure and pregnancy status.

Detachment management is surgical. The aim is to close all breaks, relieve vitreous traction and reattach the retina. Urgency depends on macular status.

Timing

• Macula-on rhegmatogenous detachment: same day to within 24 hours.
• Macula-off detachment of recent onset: surgery within 24 to 72 hours.
• Chronic macula-off detachment: semi-urgent, generally within 1 week.
• Pre-operative care includes activity restriction, head positioning according to break location, eye protection and fasting for surgery.

Retinal breaks without detachment

• Symptomatic horseshoe tears are treated promptly with laser retinopexy or cryotherapy.
• Asymptomatic round holes and lattice degeneration generally do not need treatment unless high-risk features are present.

Surgical repair

• Pneumatic retinopexy for selected superior breaks, using intravitreal gas with laser or cryotherapy and strict postoperative positioning.
• Scleral buckle for selected phakic patients, retinal dialysis, inferior breaks and atrophic holes.
• Pars plana vitrectomy for pseudophakic eyes, posterior breaks, vitreous haemorrhage, proliferative vitreoretinopathy and complex detachments, using endolaser and gas or silicone oil tamponade as appropriate.
• Combined buckle and vitrectomy for complex or inferior detachments.

Postoperative care

• Position according to the tamponade and break location.
• Avoid air travel, high altitude and nitrous oxide anaesthesia while intraocular gas remains.
• Topical prednisolone acetate 1% four times daily tapered over 4 to 6 weeks, antibiotic drops for 1 to 2 weeks, cycloplegic drops and ocular hypotensive medication as needed.
• Silicone oil is removed once the retina is stable, often after 3 to 6 months.
• Review at day 1, 1 week, 1 month and 3 months, then according to progress.

Complications

• Recurrent detachment is managed with repeat vitrectomy, membrane peeling, retinectomy and silicone oil when required.
• Monitor for raised intraocular pressure, cataract, epiretinal membrane, macular oedema, endophthalmitis, hypotony and silicone oil keratopathy.

Tractional and exudative detachments

• Tractional: vitrectomy with membrane peeling, with pre-operative anti-VEGF in selected proliferative diabetic retinopathy cases.
• Exudative: treat the underlying inflammatory, neoplastic, hypertensive or obstetric cause.

Educate high-risk patients about new floaters, flashes and field loss. Examine the fellow eye and prophylactically treat high-risk predisposing lesions where indicated.