Retinal detachment – classification

Description

A Retinal Detachment (RD) refers to the condition where the neurosensory retina lifts off and separates from the underlying Retinal Pigment Epithelium (RPE).

Classification

Possible causes of a RD include:

• Rhegmatogenous: where a full-thickness retinal break (tear or hole) allows liquid vitreous fluid to between the sensory retina and the RPE, thereby causing the retina to lift off. Possible predisposing factors include lattice degeneration, posterior vitreous detachment (PVD), trauma, intraocular surgery, and myopia.
• Tractional: where another retinal disease such as proliferative diabetic retinopathy, or retinopathy of prematurity, leads to direct fibrotic or fibrovascular traction on the retina without a break.
• Exudative: due to the accumulation of exudative material, serous fluid, or blood beneath the retina, without a retinal break or tear having occurred.
• Therapeutic: Miotic therapy, such as pilocarpine, used in glaucoma therapy may precipitate RD

Symptoms

A sudden or dramatic onset in: (1) an increased number of floaters; (2) increased flashes of light (photopsia) which does not diminish; (3) loss of peripheral or side vision; (4) the appearance of a curtain or blind coming down over vision; (5) cloudy vision, cob-webs or shadow observed.

Signs

The retina appears elevated and undulating or billowing with eye movements. While retinal blood vessels may be visible, the underlying choroidal detail is obscured. When the RD is recent, the retina may be relatively transparent, but with time the separated tissue becomes more opaque. If the detachment has been static for some months, the posterior border may be pigmented. A rhegmatogenous RD is indicated by the presence of a retinal break, often a tear, more obvious with scleral indentation. There may be pigment cells in the vitreous (Shafer’s sign), as well as reduced intraocular pressure and a relative afferent pupillary defect (RAPD).

Peripheral retinal lesions, which are not considered a predisposing condition for RD:

• Bear tracks or peripheral grouped pigmentation.
• Pavingstone/cobblestone degeneration

Signs that uncommonly lead to RD:

• Lattice degeneration, but only if extensive
• Snail track degeneration
• Peripheral cystoid degeneration
• Asymptomatic operculated tears, pigmented breaks, atrophic holes
• Post-inflammatory chorioretinal scars
• Retinoschisis, commotio retinae

Signs with significant risk for RD, in conjunction with vitreo-retinal traction:

• Asymptomatic flap or tears
• Symptomatic operculated tears or atrophic holes, or asymptomatic lesions with other risk factors as listed below.
• Symptomatic tears with persistent traction, horseshoe tears, giant tears
• Retinal dialysis, post-traumatic tears

Other risk factors: aphakia, pseudophakia, high myopia, personal or family history of retinal detachment, use of miotics.

Prevalence

Rare (approximately 1 in 10,000) in the general population, although more common in specific risk groups as mentioned above.

Significance

Acutely vision threatening

Differential Diagnosis

Retinoschisis, central serous retinopathy, choroidal detachment

Management

Urgent

A rhegmatogenous retinal detachment in which the macular is not yet involved is an ocular emergency needing treatment within 24 hours. If the macular has already detached, then treatment is still urgent, 48-96 hours.

Additional investigations

B-scan ultrasound may be used to assess the mobility of the vitreous, the presence of PVD and whether there is vitreous traction. Ocular coherence tomography may also be helpful in establishing the presence of vitreous traction. Fluorescein angiography may be helpful in evaluating exudative retinal detachment. Peripheral visual field testing (30-60°) may be required to detect field loss.

Laser treatment

Indicated for symptomatic lesions. Two or three rows of laser photocoagulation around tears or holes located posteriorly. Also appropriate to prevent progression of rhegmatogenous retinal detachment if asymptomatic and not threatening the macula.

Cryotherapy

More useful for anterior lesions, cloudy media, significant sub-retinal fluid

Surgical treatment

Options include scleral buckle, pneumatic retinopexy, plars plana vitrectomy, drainage of sub-retinal fluid. If there are underlying conditions, for example in exudative retinal detachment, then the underlying condition should be treated. If vitreoretinal traction is present, surgery to relieve the traction will be considered.