Epidemiology^[2][8]

• Incidence is about 10-15 in 100,000^[5] with a prevalence of about 0.3% of the general population and a lifetime risk of 3% by the age of 85.^[4]
• There are an estimated 7,300 new cases in the UK every year.
• It most commonly occurs in the 40-70 year-old age group (the average age is 60 years old) although traumatic retinal detachment (RD) is more frequently seen in younger patients, particularly males.
• There has recently been an increase in presentation of much younger individuals and in children associated with paint ball injuries.^[9]
• It is more frequent in men, in right eyes and with increasing affluence.
• There is anecdotal evidence that it is more common in people of Jewish descent and less common in patients of African origin.

Aetiology^[4][10]

Some individuals may be predisposed to getting a retinal detachment (RD) (eg by the morphology of the eye) or it can be caused by a number of conditions. Some of these are applicable to all types of RD (see 'Risk factors for RD' box) whereas others tend to occur more specifically in different types of RD. In a large number of people, it is preceded by a posterior vitreous detachment (PVD) - the end point of a lifetime of normal, age-related degenerative liquefaction and shrinkage of the vitreous. Patients with a PVD carry a 10-15% risk of going on to developing an RD as the PVD may cause a tear in the retina.

Rhegmatogenous RD This may occur in the presence of conditions predisposing to a retinal break:

• Age.
• Lattice degeneration.
• Aphakia (no crystalline lens).
• Age-related retinoschisis.
• Previous retinal break.
• Marfan's syndrome.

Non-rhegmatogenous tractional RD Any fibrous bands in the vitreous can predispose the patient. These may occur in conditions such as:

• Proliferative diabetic retinopathy.
• Penetrating eye injury.
• Retinal vein occlusion.
• Retinopathy of prematurity.
• Previous giant retinal tear.
• Sickle cell retinopathy.
• Toxocariasis.

Non-rhegmatogenous exudative RD

• Inflammatory conditions, eg uveitis, Vogt-Koyanagi-Harada syndrome, posterior scleritis.
• Vascular disease, eg severe hypertension, Coats' disease.
• Neoplasia, eg multiple myeloma, tumours of the choroid, haemangioma.
• Toxaemia of pregnancy.
• Congenital abnormalities, eg coloboma.
• Maculopathy, eg neovascular macular degeneration, idiopathic central serous chorioretinopathy.
• Nanophthalmos.

Other more unusual reported causes of RDs have been following laser treatment for posterior capsular opacification (a condition that develops months or years after cataract operations that is amenable to laser treatment) and latanoprost use.^[9] Intravitreal injections for age-related macular degeneration are now commonplace but the incidence of RD associated with this appears to be very low.^[11]

Presentation

History^[1]

• The classic symptom is photopsia (flashing lights) which occurs in about 60% of patients. This tends to be induced by eye movements and is best seen in dim lighting conditions, particularly in the temporal, peripheral visual field. Where there is a pre-existing posterior vitreous detachment (PVD), it arises as a result of the vitreous pulling on the retina. The location of the flashes in the patient's field of vision is unrelated to the location of the tear.^[3]
• Photopsia is commonly associated with floaters which may be described as a solitary opacity, a cobweb-like opacity or a shower of little spots. The latter is pathognomonic for vitreous haemorrhage, resulting from disruption of a retinal vessel caused by a retinal tear or mechanical traction of a vitreoretinal adhesion.^[3] Where a PVD has already occurred, they are more visible to the patient as they are more mobile within the globe.^[4]
• Some patients go on to describe a visual field defect apparent as a curtain descending over their vision. This may become worse as the day goes on. If the macula becomes involved, visual acuity is severely reduced and there may be metamorphopsia (distortion of the image). These are late symptoms of retinal detachment (RD) and the location of the field defect is very specific to the location of the tear.^[3]
• A simple tear in the absence of detachment may be completely asymptomatic.^[12]

Examination^[13]

You may wish to visit the separate article Examination of the Eye for details on carrying out these assessments.

• Visual acuity - this should be checked in all patients, before dilating the pupil. If you strongly suspect an RD and the visual acuity is normal, referral is all the more urgent as the macula has not yet been involved and surgery can prevent it from becoming detached. A poor visual acuity suggests that the macula has already become detached - these patients do need urgent referral but their outcome is less promising. It may also suggest a vitreous haemorrhage.
• Visual fields - confrontational visual field testing will give you an idea of any gross visual defects corresponding to the area of detached retina - defects may not be picked up this way if they are small.
• Dilated fundal examination - only do this after you have assessed the visual acuity and ruled out the presence of a relative afferent pupillary defect (RAPD) - this indicates extensive RD.^[14] Dilate the pupils - 1% tropicamide is suitable; warn the patient that their vision will become blurred and that therefore they will not be able to drive (this settles over 2-3 hours). A large detachment can be seen as a sheet of sensory retina billowing towards the centre of the globe, over which the vessels pass like paths over a hill. There may be an associated tear visible. Note that the location of the photopsia in the patient's visual field bears no relation to where the tear is but the location of the field loss does.^[3]

If you cannot see an RD on ophthalmoscopy but suspect it, refer the patient on for a slit-lamp examination (direct ophthalmoscopy offers only a narrow field of view). If you have access to a slit lamp, look for cells in the anterior chamber and the presence of 'tobacco dust', seen as grey-red specks just behind the pupil. This is associated with a 90% risk of a retinal break. A vitreous haemorrhage is associated with a 70% risk of a retinal break.

Ultimately, these patients will be fully re-examined in the eye casualty department. This will involve a slit-lamp examination, indirect ophthalmoscopy (a head-mounted ophthalmoscope shining light through a wide-angled lens to allow a more peripheral look) or they will have a Goldmann triple mirror examination (which involves a slit lamp and a contact lens applied against the anaesthetised cornea for a few minutes as the peripheral retina is examined).

Some patients may also have an ultrasound scan performed where they simply have to lie back with their eyes closed as the probe is applied over the eyelid. Ophthalmologists will be assessing the type and extent of the detachment, the type, extent and number of any associated tears and any ocular comorbidity.

The fellow eye^[15]

Whenever you are presented with an ocular problem, always ask about - and assess - both eyes. RD is most frequently a unilateral condition but a recent study looking at cases of rhegmatogenous RD highlighted the fact that about 7% of these patients have detachments in both eyes (some have suggested that the figure is as high as 15%^[3]). In these patients, there is a significant threat to their overall vision so it is particularly important to pick these up and not to dismiss bilateral flashing lights as a migraine (see 'Differential diagnosis', below). It is worth noting that in this study, the fellow eye was more likely to be involved if there had been previous cataract surgery and in patients who were highly myopic (ie very short-sighted).

Differential diagnosis

Conditions with similar symptoms:

• Photopsia:
  • Posterior vitreous detachment (PVD): this may lead to a retinal detachment (RD) (see above).
  • Atypical/ocular migraine.
  • Optic nerve pathology eg optic neuritis.
  • Cerebrovascular event/transient ischaemic attacks.
  • Choroidal tumours.
• Floaters:^[4]
  • PVD.
  • Vitreous haemorrhage (eg diabetic retinopathy).
  • Age-related macular degeneration.
  • Asteroid hyalosis.
  • Uveitis (particularly posterior).
  • Retinitis pigmentosa.

Conditions with similar signs:

• Retinoschisis: usually a benign condition where the retina is split into layers.
• Choroidal detachment: detachment of the vascular layer of the eye.
• Uveal effusion syndrome: rare idiopathic condition characterised by self-limiting choroidal and retinal detachment.

Additionally, when the diagnosis is confirmed, there will be efforts to rule out any underlying predisposing factors that need to be treated, eg tumour (see list above).

Investigations

Diagnosis is confirmed on examination and any further investigations relate to the suitability of the patient to have a general anaesthetic. Occasionally, an ultrasound scan (a simple procedure done in the outpatient clinic) or optical coherence tomography are needed to confirm the diagnosis or further assess the eye in order to prepare for surgery. CT and MRI scans only have a role if there is a tumour or suspected foreign body. Patients with an exudative retinal detachment (RD) benefit from a full systemic examination, owing to its more frequent association with systemic disease.^[7]

Management

Medical treatment

Generally, retinal breaks and detachment are treated with lasers and surgically respectively. However, exudative RDs caused by inflammatory conditions may respond best to treatment of the underlying condition.^[6] All other forms of RD need active intervention.

Laser treatment

This is performed if there is a retinal break but a full-blown RD hasn't yet developed (or if it is very small). The idea is to encircle the lesion with laser burns. The subsequent scar tissue prevents the tear from extending or subretinal fluid from leaking in or out of it. This can be done within a clinic setting. Laser treatment is sometimes also used as an adjunct to scleral buckle surgery (see 'Surgical treatment', below).

Cryotherapy

This treatment modality may be selected in preference to laser treatment if the tear is in certain locations around the fundus, if the view is a little hazy or the pupil is small.

Surgical treatment

There are three approaches to surgical treatment, the first two of which are the most commonly used:^[16]

• Scleral buckle - a silicone sponge or solid silicone explant is placed on the outside of the globe at the site of retinal breaks, indenting the sclera and so bringing this into apposition with the loose retina. The breaks themselves are treated with laser or cryotherapy. The idea is to close off the breaks and to reduce any associated vitreal traction. The explants may be short stumps placed locally or longer structures encircling the circumference of the globe. The choice depends on the nature of the break(s).
• Vitrectomy - the vitreous may be removed in the case of a tractional RD. This technique is also now increasingly used in rhegmatogenous RD, although there is considerable inter-surgeon variation.^[7]
• Pneumatic retinopexy - a gas bubble (sometimes a silicone bubble) is injected inside the globe, over the site of the break (which has either previously been repaired with cryotherapy or is subsequently repaired with laser therapy) and pushes the flaps of retina against the periphery. If it stays in position, it permits the subretinal fluid to be resorbed over 24-48 hours. The bubble itself will very gradually be resorbed over weeks/months.This procedure is favoured in North America and less commonly used in the UK^[4] It is only suitable for a minority of straightforward cases.^[14]

There are a few things that are helpful to know about surgical repair of RD:^[5]

• It is carried out by specialist vitreoretinal surgeons (so patients may find themselves being referred on from a DGH).
• Most RDs not involving the macula are repaired the same day and those involving the macula are repaired within five days.^[4] Those patients who do not have immediate surgery may be advised strict bedrest and to hold the head in a particular position to prevent progression of the detachment.^[5]
• Surgery may be carried out under a local or general anaesthetic, depending on the type of repair undertaken.
• It may involve 'posturing': the gas or silicone bubble has to stay in the right place by keeping the head very still in a particular position. The position depends on where the tear is. This can be for up to 10 days.
• It may be done as a day case or involve a few nights' stay (not usually longer than two or three nights) at the hospital.
• Topical antibiotics and corticosteroids are routinely prescribed postoperatively; occasionally, patients may also need cycloplegics and ocular hypotensive drugs.^[4]
• Following discharge, patients should report excessive pain, worsening vision or an increasingly red eye to the team. Headaches and nausea should also be reported (this could be rising intraocular pressure).
• Patients who have had pneumatic retinopexy should not travel by air and should advise anaesthetists that they have intraocular gas prior to any subsequent general anaesthetic. The team will inform the patient when these activities are safe. They will notice a gas-fluid interface in their lie of vision (an undulating line) that moves downwards over weeks/months (depending on what was injected in).
• Unfortunately, a successful re-attachment doesn't always result in a good visual outcome.^[4] For example, vision post-vitrectomy may remain impaired for weeks or months and scleral buckle surgery can result in diplopia (~3% of cases).^[14]

Complications

• Untreated retinal detachment (RD). Some retinal breaks and RDs are long-standing problems that are incidentally picked up. These are more likely to be stable but should be monitored and, depending on the site and size, repair carried out on an elective basis. All new problems should be treated, as they may lead to extensive detachment and ultimately, sight loss.
• Laser treatment. Complications are uncommon. If these do occur, they may include maculopathy (such as oedema), choroidal detachment, a secondary tear or haemorrhage.
• Cryotherapy. There is often an associated transient lid chemosis. Other complications include transient diplopia, vitritis (inflammation of the vitreous) and rarely, maculopathy.
• Complications of surgical treatment.^[1] These are relatively uncommon and patients will be advised individually depending on the nature of their RD and surgery. Generic complications include infection and haemorrhage (severe enough to cause loss of vision in <1% of cases^[14]), iatrogenic retinal break during the procedure (~5%), retinal incarceration (where the retina folds and gets pulled up into the break) and a paradoxical gaping of certain types of retinal break. Poor visual recovery and the need for a further procedure (due to re-detachment of the retina) are also possible. Rarely, a silicone explant may dislodge or even ulcerate out through the conjunctiva or the skin.

Prognosis^[5]

Untreated, rhegmatogenous retinal detachments (RDs) almost always lead to a blind eye but early and appropriate intervention can be associated with an excellent outcome.^[7] Tractional RDs tend to be slowly progressive but may have long periods of being static. Exudative RDs may fluctuate according to the underlying disease process.

• Patients who have simply needed laser treatment or cryotherapy for a tear without detachment should expect a full recovery.
• For those requiring surgery, the outcome has been steadily improving over the past two decades in the UK.^[5] However, it does depend upon the length of time that the retina has been detached, the underlying mechanism of the RD and whether the macula is involved: prognosis is related inversely to the degree of macular involvement and the length of time the retina has been off.^[6] Recovery depends on the site and extent of the RD. Surgery by a subspecialist is associated with an 87% success rate after one operation and >95% after two or more procedures.^[14]
• Proliferative vitreoretinopathy is associated with a higher failure rate.^[6]
• A patient presenting late with a 'macula-off' RD has a very bleak outlook. Early and prompt presentation/treatment increase the chances of good recovery with restoration of most of the vision. It may take several weeks for the vision to improve after surgery (particularly if there is a gas/silicone bubble in situ) and patients may go on to need additional spectacles or other visual aids.
• There is about 10% chance of an RD developing in the fellow eye in phakic patients (ie those who have their lens in situ) and 20-36% chances of developing RD in the fellow eye in pseudophakic patients (those who have had the lens replaced, eg due to cataract).^[6]
• Only a very small number of patients have a recurrence of the original detachment.^[17]

Prevention

A rhegmatogenous retinal detachment (RD) can be prevented if the retinal break is diagnosed and treated prior to the accumulation of subretinal fluid.