A Curtain Descends

Retinal detachment

This is the separation of the sensory retina from the underlying pigmented retinal epithelium.

Findings:

• ultrasound — The detached retina is visible as a free floating echogenic membrane separated from the globe posteriorly. It moves with eye movement and is attached at the optic disc.
• ophthalmoscopy — The detached retina appears corrugated and partially opaque. On funduscopy the detached portion will appear out of focus.

There are 3 types of retinal detachment:

• rhegmatogenous — the detached retina is elevated by underlying fluid that collects from the vitrous through a tear in the retina. This is the most common mechanism. It may be related to trauma, but is more common in men, those over age 45 years and those with myopia.
• exudative — fluid collects from retinal vessels. The causes may be neoplastic, inflammatory, congenital, or vascular in nature and include hypertension, prececlampsia, central retinal venous occlusion (CRVO), glomerulonephritis, papilledema, vasculitis, and choroidal tumours.
• tractional — the retina is pulled up by fibrocellular bands. This occurs in conditions such as proliferative diabetic retinopathy, sickle cell disease, retinopathy of prematurity(ROP), previous vitreous hemorrhage, trauma, and toxocariasis.

History

• painless loss of vision (central, peripheral or both)
• Recent history of increased numbers of flashes (due to traction on the retina) and floaters (due to hemorrhage and debris in the vitreous).
• presence of a dark shadow or curtain moving over the visual field of the affected eye.

Examination

• Visual acuity — reduced if the macula is involved.
• Red reflex — abnormal; a mobile detached retina may be visible.
• Visual fields — reduced.
• Pupils — a mild relative afferent pupillary defect (RAPD) may be present depending the size of the retinal detachment.
• Ophthalmoscopy — The detached retina appears corrugated and partially opaque. On funduscopy the detached portion will appear out of focus.
  Other features that may be seen include: anterior vitreous pigmented cells, vitreous hemorrhage, and posterior vitreous detachment.

The slit lamp and ultrasound findings are shown in a short but enlightening video at RootAtlas.com. Ocular ultrasound findings are also demonstrated in EMRAP.TV Episode 17: Retinal detachment.

Direct funduscopy in the emergency department cannot rule out retinal detachment — ultrasound is a useful investigation for diagnosing retinal detachment in the ED. The sonographic features of retinal detachment are lucidly explained and demonstrated at ultrasoundvillage.com.

• Urgent ophthalmologist opinion.
• minimise activity —- bed rest with toilet privileges.
• Treatment of underlying cause (especially if exudative).
• Surgical options include laser photocoagulation, cryotherapy, pneumatic retinopexy, vitrectomy, and scleral buckle.
• Close follow up is required.

A retinal break is a tear in the retinal membranes and may or may not lead to retinal detachment.

Retinoschisis should be considered in the differential of retinal detachment. It refers to the splitting of the retina, which has X-linked juvenile and age-related degenerative forms. It may be asymptomatic or lead to vision loss due to macular involvement and vitreous hemorrhage. It may be amenable to surgery.