Retinal detachment

Description

Retinal detachment is the separation of the retina (the light-sensitive membrane at the back of the eye) from its supporting layers. The detachment may be due to local accumulation of fluid between the two layers, or the retina may be pulled away by traction from the vitreous, the gel which fills the eyeball. Retinal separation may begin as a small patch, but may spread to involve the whole retina, causing blindness. It can affect up to 10,000 people per year.

There are different types of retinal detachment - such as posterior vitreous detachment, retinal holes or retinal tears, each with its own treatment protocol.

Possible causes and risk factors

• Retinal detachment is more common in the elderly, and those with myopia(short-sightedness)
• Trauma to the eye
• Family history of retinal detachment
• Detachment may occur on its own, with no cause ever being found.
• Some cases are related to poorly-controlled diabetes, or to trauma.
• It occurs more often after surgery for cataracts, with a 30% risk of its happening in both eyes.
• It normally affects one eye only, but there is a 15% risk of the other eye also being affected.

Symptoms

These may vary slightly according to the way in which the detachment starts, but common symptoms are:

• sudden increase in the number of floaters
• flashes of light in the periphery of vision
• showers of black spots - due to bleeding in the eye
• loss of peripheral vision (at the edges)

Diagnosis

Suspected retinal tears must be referred urgently to a specialist ophthalmologist (eye surgeon) for immediate investigation and treatment in order to prevent blindness.

Clinical examination of the eye will include

• full direct and indirect dilated ophthalmoscopy
• slit-lamp examination
• visual fields, acuity, and refraction testing
• testing of papillary reflexes
• measuring pressure inside the eye
• special imaging procedures such as fluorescein angiography, ultrasound.

Treatment and outcome

The aim of treatment is to return the retina to its normal position, keep it there, and prevent the problem from progressing or recurring.

Some patients with vitreous detachment, but no retinal tear may need no intervention. They are reassured that the floaters will settle below their line of vision over the next few months, and will no longer be a nuisance.

With true retinal detachment, several treatment approaches are possible:

• laser coagulation
• cryoretinopexy - using cold to re-attach the retina
• pneumatic retinopexy - a gas bubble inside the eye is used to push the retina back onto the inside of the eyeball. 70 - 80% of cases respond to this procedure.
• scleral buckle - an operation to pinch the outside of the eyeball from behind, so that the retina can resettle onto the inside without being stretched. This has an 80-90% success rate.
• vitrectomy - removal of the vitreous(the gel that fills the eyeball), flattening of the retina with a gas bubble, and replacement of the removed vitreous with a substitute, such as silicone oil. This has a high success rate, 80-90%, but nearly all patients over the age of 50 having this procedure go on to develop cataracts.

Prevention

It is impossible to prevent a spontaneous retinal detachment. However, education about early intervention can prevent long-term complications such as blindness.

Cataract surgery is a major risk factor, so anything which can reduce the need for cataract surgery will have an impact on retinal detachment. Strict glucose control in diabetics has a role here.

Reducing trauma is problematic, as most cases are accidental. Boxing and bungee-jumping are associated with direct trauma and acceleration-deceleration type injuries.