Typical symptoms are the new onset of flashing lights, floaters and the appearance of a grey curtain.

Patients with suspected retinal detachment need to be urgently assessed and treated to minimise the extent of visual loss which can be severe.

Retinal detachment is rare. There are three types of retinal detachment:

·         Rhegmatogenous retinal detachment

·         Tractional retinal detachment

·         Exudative retinal detachment

Rhegmatogenous retinal detachment is the most common type.

The name rhegmatogenous comes from the Greek word ‘rhegma’ meaning break and signifies the presence of a retinal tear.

In 2019, a meta-analysis of five studies showed that the annual incidence of rhegmatogenous retinal detachment was 13.3 per 100,000 [1]. It was noted that there has been limited research into the epidemiology of retinal detachment.

In a Scottish study completed in 2010 [2], the incidence was found to be 12.05 per 100,000 with the peak incidence in the 60- to 69-year age group. Males were more commonly affected than females.

RHEGMATOGENOUS RETINAL DETACHMENT

To start with, I am going to describe rhegmatogenous retinal detachment in detail. After that, I will look at traction and exudative retinal detachment.

THE UNDERLYING DISEASE MECHANISM

The retina lines the posterior chamber of the eye.

The main component of the posterior chamber is the vitreous body. This is a roughly spherical blob of transparent gel. It is made up of water, hyaluronic acid and a fine network of collagen fibres. It is surrounded by a thin sheet of collagen, the hyaloid membrane.

Wrapped around the vitreous body are three layers of tissue. The retina is the first. It extends from the border of the ciliary body anteriorly to the insertion of the optic nerve posteriorly. The circumferential, transitional area between the retina and the ciliary body is called the ora serrata.

The choroid lies outside the retina. It, again, extends from the ciliary body to the insertion of the optic nerve.

The final layer is the sclera. Anteriorly this covers part of the anterior chamber as far as the edge of the cornea. Posteriorly, it merges with the dural sheath of the optic nerve.

These components of the posterior chamber are held together by a variety of forces. However, there are two areas of potential weakness where they can come apart:

·         The vitreous body can become separated from the adjacent, internal limiting membrane of the retina leading to a posterior vitreous detachment.

·         The neurosensory retina can become separated from its supporting retinal pigment epithelium (RPE) leading to a retinal detachment.

The retina is made up of neurosensory tissue that rests on the retinal pigment epithelium, its outermost layer.

The retinal pigment epithelium consists of a single layer of pigmented cells. The pigmented cells absorb light preventing its reflection and scatter inside the eye. The retinal pigment epithelium is also involved in the phagocytosis and recycling of cellular matter from the photoreceptor cell layer. It makes up part of the blood retinal barrier.

The neurosensory retina consists of photoreceptor cells (rods and cones), a variety of nerve cells, nerve fibres and glial (supporting) cells. The nerve cells process information from the photoreceptor cells and convey it to the optic nerve and, from there, to the brain.

The retina can itself be subdivided into ten layers according to the position of the different cell types that it contains.

I am not sure that it is helpful to memorise all the different layers of the retina. However, I think it is worth noting that the layer of photoreceptor cells lies immediately inside the retinal pigment epithelium and gets its blood supply from the choroid. The other, inner layers of the neurosensory retina get their blood supply from the central retinal artery and its branches. As I have indicated, in a retinal detachment, the photoreceptor cell layer becomes separated from the retinal pigment epithelium. This will cut off its blood supply causing death of the photoreceptor cells.

The choroid is part of the uvea. It is composed of richly vascular tissue that supplies oxygen and nutrients to the outer, photoreceptor layer of the retina. The choroid contains a high proportion of melanocytes which, like those in the retinal pigment epithelium, absorb excess light.

The sclera (white of the eye) is the white, fibrous, outer capsule that supports and protects the eye. It provides attachments for the external ocular muscles.

The internal limiting membrane of the retina is firmly fixed to the vitreous body at several points:  at the vitreous base which straddles the ora serrata, around the margins of the optic nerve, around the macula and at the point of entry of the retinal vessels. The remainder of the retina is much less strongly attached.

As we get older, the vitreous gel deteriorates. The vitreous body shrinks and areas of it liquify. Shrinkage of the vitreous body pulls it away from the retina. Where the two structures are securely attached, tractional forces can tear the retina. Sometimes small, round holes are produced rather than tears.

A horseshoe or U-shaped tear is a large tear that leaves a free flap of retinal tissue.

Fluid from the vitreous can seep through any full-thickness retinal tears and into the potential space (subretinal space) between the retinal pigment epithelium and the neurosensory retina. The fluid forces these two layers apart, in effect detaching the neurosensory retina. Detachment of the neurosensory retina cuts off the blood supply to the photoreceptor cells. These cells quickly die causing an area of visual loss. If the fluid spreads out, the area of detachment and visual loss enlarges.

If the macula is involved in the detachment, central vision will be lost.

At any one time, there may be one retinal tear or several. To ensure optimal treatment, it is very important to identify all tears.

Not all retinal tears result in retinal detachment. A retinal hole rarely causes retinal detachment.

BLUNT TRAUMA

The impact of blunt trauma can cause the vitreous body to move within the posterior chamber. Shearing forces acting on the attachments between the vitreous and retina can cause the retina to tear. This is one of the causes of retinal detachment in younger patients.

POSTERIOR VITREOUS DETACHMENT

Age related deterioration and shrinkage of the vitreous body occurs mostly without the development of retinal tears or holes and leads to posterior vitreous detachment.

Patients present with floaters and, sometimes, flashing lights. Vitreous haemorrhage may occur. Posterior vitreous detachment is a very common cause of floaters.

A Weiss ring may be noticed by the patient and visible to the examiner. This is a dark ring representing the original attachment of the vitreous around the insertion of the optic nerve.

The detached hyaloid membrane may be seen on slit lamp examination.

In the long term, floaters usually become less noticeable.

Most patients with posterior vitreous detachment do not need treatment. It is occasionally used for large, persistent floaters or vitreous haemorrhage.

Note: retinal tears or detachment have been shown to be present in 9.9% of patients with posterior vitreous detachment [3]. It is extremely important to look carefully for any retinal tears or detachment in these patients.

RISK FACTORS FOR RETINAL DETACHMENT

·         Increasing age: over 60 years.

This is probably the most important risk factor. It leads to deterioration of the vitreous gel, vitreous detachment and, sometimes, retinal tears and detachment.

·         Lattice degeneration of the retina.

This is quite common and occasionally leads to retinal detachment. The thin, fragile retina and adhesions between the retina and the vitreous make the retina susceptible to tears.

·         High myopia (severe shortsightedness).

The eye is elongated causing the retina to be thin and stretched making it susceptible to tears. Lattice degeneration is also more common in myopic patients.

·         Cataract surgery.

Retinal detachment is a complication of cataract surgery. It has been suggested that it may be secondary to intraoperative loss of vitreous material or an increase in tractional forces between the vitreous and retina.

·         Previous history of retinal tear or detachment.

·         Family history of retinal detachment.

CLINICAL FEATURES

A small retinal detachment may be ignored or not noticed by the patient. Typical symptoms are the new onset of flashing lights, floaters and the appearance of a grey curtain.

Flashing lights are thought to be due to stimulation of photoreceptor cells, in the case of a retinal detachment, by traction.

Floaters result from debris in the vitreous gel. This can be caused by collagen fibres clumping together, cellular matter in the vitreous or red blood cells. Cells are released into the vitreous gel when the retina or vitreous are damaged. Floaters are common and, often, do not indicate serious pathology.

The patient may notice an area of loss of vision that may be described as a dark curtain, shadow or cloud. It corresponds to the area of retinal detachment and photoreceptor cell death. It is usually peripheral.

A retinal detachment can occur abruptly or may develop over days or weeks.

In a large retinal detachment, an afferent pupillary defect may be present. Occasionally, the area of detachment may be visible when inspecting the red reflex. There will be a visual field deficit in the area of the detachment.

A marked reduction in visual acuity usually indicates detachment of the macula or a vitreous haemorrhage.

AFFERENT PUPILLARY DEFECTS (MARCUS GUNN PUPIL)

Normally, if light is shone into one eye, both pupils constrict. If a large retinal detachment is present, less light will register in the affected eye, and the degree of constriction will be reduced. As a practical way of testing this, the light is initially shone into the normal eye causing constriction, then moved to the other eye causing the pupils to dilate relative to their constricted position. If both eyes are normal, there would be no change in pupil size when the torch was moved.

Other causes of an afferent pupillary defect include optic neuritis, optic atrophy and central retinal artery occlusion.

INDIRECT OPHTHALMOSCOPY

To carry out indirect ophthalmoscopy, the operator wears a head lamp and uses a hand-held lens to see the retina. A probe can be used to depress the sclera. The patient usually lies prone with dilated pupils and, ideally, anaesthetized eyes.

Retinal tears may be difficult to see and are often situated peripherally. To ensure that any tears or a small detachment are identified, the whole retina needs to be carefully examined. This should be done by an experienced ophthalmologist or optometrist using indirect ophthalmoscopy. Depression of the sclera during the procedure can give an enhanced view of the peripheral retina and make any tears more obvious.

Pigmented cells in the vitreous gel (tobacco dust) are very suggestive of a retinal tear. This is called Shafer’s sign. These cells are released by damage to the retinal pigment epithelium.

The detached area of retina may be pale or grey in colour. The fluid between the neurosensory retina and the retinal pigment epithelium can cause the retina to project inwards producing a bulge into the vitreous. Presumably, any significant outward protrusion would be limited by the rigidity of the sclera. The surface of the detached area is often undulated with folds of loose retinal tissue. Changing the position of the patient’s head can cause the fluid to move.

A retinal detachment may be associated with a vitreous haemorrhage. This may prevent a good view of the retina. In the presence of a vitreous haemorrhage, ultrasound may be helpful in demonstrating retinal tears or detachment.

Once the affected eye has been examined, it is very important to check the other eye for risk factors for retinal detachment.

VITREOUS HAEMORRHAGE

The onset of vitreous haemorrhage is usually sudden and painless. It can cause blurred or hazy vision, multiple floaters, cobweb like shadows, red discolouration and areas of loss of vision (scotomas). Vision may be worse in the morning if the blood settles over the macula when the patient lies down in bed. Bleeding may be diffuse. Extensive bleeding may obscure the retina completely. In a subhyaloid haemorrhage (bleeding between the retina and the hyaloid membrane of the vitreous body), the blood is often in a curved ‘boat shape’ with an upper fluid level.

INVESTIGATIONS

OCULAR ULTRASOUND

This may help identify a retinal detachment if the retina is obscured by a dense cataract or vitreous haemorrhage. It can also help differentiate a rhegmatogenous retinal detachment from an exudative retinal detachment or retinoschisis.

OPTICAL COHERENCE TOMOGRAPHY (OCT)

This is a non-invasive test that uses light waves to take high resolution cross-sectional images of the retina and choroid.

Like ultrasound, optical coherence tomography can help confirm the diagnosis and differentiate retinal detachment from retinoschisis. It can also be used to assess the extent of the detachment and whether the macula is involved.

TREATMENT

As I have said, urgent assessment and, if indicated, urgent treatment are required to minimise any loss of vision. The goal of treatment is to seal any retinal tears, drain sub retinal fluid and attach the retina back onto the retinal pigment epithelium.

In retinal tears without detachment, laser or cryotherapy can be used to seal the retinal break.

PNEUMATIC RETINOPEXY

This is a straightforward procedure for a small retinal detachment. A gas bubble is injected into the vitreous. The pressure of the gas pushes the detached retina against the retinal pigment epithelium (tamponade). This squeezes out any fluid and helps maintain contact between the separated surfaces. The tear can then be sealed by laser or cryotherapy.

Complications of retinopexy include infection (endopthalmitis), vitreous haemorrhage, gas migration into the anterior chamber, cataract, further retinal tears or detachment.

To avoid ocular damage due to excessive expansion of the gas, patients who have had retinopexy or vitrectomy with gas tamponade cannot fly or travel at high altitude until the gas is absorbed, usually over two to three months.

Postoperative head positioning is thought to help keep the gas over the area of detachment: gas tends to rise so face down positioning may be used for a posterior detachment.

VITRECTOMY

Once the eye is fully developed, the vitreous gel has limited functional value. In a vitrectomy, subretinal fluid is drained and any tears are sealed. The vitreous gel is broken up with a vitreous cutter and removed. The resulting space is filled with gas or oil. Removing the vitreous prevents traction on the retina and further tears. It will also get rid of any persistent vitreous haemorrhage obscuring the field of vision.

If oil is used, it needs to be extracted at a later date.

Complications of vitrectomy include infection (endopthalmitis), vitreous haemorrhage, cataract, raised intraocular pressure, further retinal tears or detachment.

SCLERAL BUCKLE SURGERY

A silicon band is fixed around the globe of the eye so that it is compressed and indented. If correctly positioned, this pushes the detached neurosensory retina against the retinal pigment epithelium allowing healing to occur and preventing further detachment. The silicon band can be left in place indefinitely.

Complications of scleral buckle surgery include infection (orbital), haemorrhage, myopic change, raised intraocular pressure, anterior ocular ischaemia, macular oedema and double vision (due to interference with the extraocular muscles).

In some patients a combination of scleral buckle and vitrectomy are used.

The surgical method chosen depends on the size of the tears, the number and position of tears, the size of the detachment, other eye problems and the experience and expertise of the surgeon.

The long-term results of the surgical treatment of retinal detachment appear to be good. A small study carried out in Scotland and published in 2025 [4], demonstrated that visual acuity was well preserved for at least ten years in many patients, whichever surgical method was chosen.

TRACTIONAL RETINAL DETACHMENT

The commonest cause of tractional retinal detachment is proliferative diabetic retinopathy. It can also be caused by the retinopathy of prematurity, sickle cell retinopathy and trauma.

Gradual shrinkage of newly formed retinal fibrous tissue lifts the neurosensory retina away from the retinal pigment epithelium. Fibrous bands (striae) may be seen. Because traction is the main mechanism of detachment, the detached area of retina adopts a concave appearance

As the process of traction is gradual, patient do not usually experience flashing lights.

Surgical treatment is an option if the macula is threatened.

EXUDATIVE RETINAL DETACHMENT

This is an accumulation of fluid in the subretinal space without evidence of any retinal breaks.

Excess fluid produced in the choroid diffuses into the subretinal space. It lifts the retina away from the retinal pigment epithelium and causes a detachment.

The detached area of retina can be seen as a bulge with no corrugations or folds.

Exudative retinal detachment can be caused by tumours such as choroidal melanoma and inflammatory conditions. These include scleritis and uveitis (iritis), systemic lupus erythematosus, Wegener’s granulomatosis and dermatomyositis.

Treatment is usually targeted at the underlying condition.

RETINOSCHISIS

This is a degenerative condition of the retina that can cause splitting of the neurosensory retina and look similar to a retinal detachment. Occasionally, it can lead to retinal detachment or vitreous haemorrhage. Optical coherence tomography can help differentiate it from retinal detachment.

REFERENCES

1.      Li JQ, Welchowski T, Schmid M, Holz FG, Finger RP. Incidence of Rhegmatogenous Retinal Detachment in Europe – A Systematic Review and Meta-Analysis. Ophthalmologica. 2019;242(2):81-86. doi:10.1159/000499489

2.      Mitry D, Charteris DG, Yorston D, et al. Rhegmatogenous retinal detachment in Scotland: research design and methodology. BMC Ophthalmol. 2009;9:2. Published 2009 Mar 24. doi:10.1186/1471-2415-9-2

3.      Nixon TRW, Davie RL, Snead MP. Posterior vitreous detachment and retinal tear – a prospective study of community referrals. Eye (Lond). 2024;38(4):786-791. doi:10.1038/s41433-023-02779-3

4.      Hazelwood JE, Mitry D, Singh J, Bennett HGB, Khan AA, Goudie CR. The Scottish Retinal Detachment Study: 10-year outcomes after retinal detachment repair. Eye (Lond). 2025;39(7):1318-1321. doi:10.1038/s41433-025-03613-8