Retinal Detachment
Retinal detachment (RD) is a sight-threatening condition in which the neurosensory retina separates from the underlying retinal pigment epithelium (RPE). This separation disrupts the normal metabolic exchange between the retina and the choroid, resulting in retinal dysfunction and, if left untreated, irreversible vision loss.
Retinal detachment is considered an ophthalmic emergency and requires prompt diagnosis and treatment to preserve vision.
Epidemiology
Rhegmatogenous retinal detachment is the most common type of retinal detachment, with an incidence of approximately 10–20 cases per 100,000 population annually.
The condition occurs more commonly in middle-aged and older adults due to age-related vitreous degeneration and posterior vitreous detachment.
The risk is significantly increased in patients with:
- High myopia
- Previous cataract surgery
- Ocular trauma
- Lattice degeneration
- A history of retinal detachment in the fellow eye
Classification
Retinal detachment is broadly classified into three major categories:
- Rhegmatogenous retinal detachment
- Tractional retinal detachment
- Exudative retinal detachment
Rhegmatogenous retinal detachment
The term rhegma means a break or tear.
Rhegmatogenous retinal detachment occurs when a full-thickness retinal break allows liquefied vitreous to pass into the subretinal space. This is the most common form of retinal detachment.
Tractional retinal detachment
Tractional retinal detachment occurs when fibrovascular membranes exert mechanical traction on the retina without the presence of a retinal break.
The most common cause is proliferative diabetic retinopathy.
Other causes include:
- Retinopathy of prematurity
- Penetrating ocular trauma
- Proliferative vitreoretinopathy
- Retinal vascular occlusions
Exudative retinal detachment
Exudative (serous) retinal detachment occurs due to the accumulation of fluid beneath the retina without a retinal break or significant traction.
Possible causes include:
- Inflammatory disorders
- Choroidal tumours
- Severe hypertension
- Central serous chorioretinopathy
- Vogt–koyanagi–harada disease
- Posterior scleritis
Risk factors
Several factors increase the risk of retinal detachment.
High myopia
High myopia is one of the most important risk factors because increased axial length predisposes the retina to thinning and lattice degeneration.
Previous cataract surgery
The risk is particularly increased when surgery is complicated by posterior capsule rupture or vitreous loss.
Ocular trauma
Ocular trauma may produce retinal tears directly or indirectly through vitreoretinal traction.
Retinal detachment may occur immediately following injury or develop several months later, particularly after blunt ocular trauma.
Lattice degeneration
Lattice degeneration is present in a significant proportion of patients with rhegmatogenous retinal detachment.
Family history
A family history of retinal detachment increases the risk of developing the condition.
Previous retinal detachment
A previous retinal detachment in one eye significantly increases the likelihood of detachment in the fellow eye.
Clinical Features
The symptoms of retinal detachment are often characteristic.
Flashes of light (Photopsia)
Patients frequently report flashes of light caused by vitreoretinal traction.
Floaters
Floaters may occur due to vitreous degeneration, retinal pigment epithelial cells, or vitreous haemorrhage.
A sudden increase in floaters is particularly concerning.
Visual field defect
As detachment progresses, patients often describe a curtain, veil, or shadow gradually moving across their field of vision.
Visual loss
Peripheral visual loss is usually followed by central visual deterioration if the macula becomes detached.
Pain
Retinal detachment is usually painless.
Clinical examination
Visual acuity varies according to macular involvement.
A macula-on detachment may preserve central vision, whereas a macula-off detachment typically causes significant visual loss.
Indirect ophthalmoscopy
Indirect ophthalmoscopy remains the gold standard for diagnosis.
The detached retina typically appears:
- Elevated
- Corrugated
- Mobile
Retinal tears, holes, lattice degeneration, and vitreoretinal traction should be carefully identified.
The location and extent of the retinal detachment should be carefully documented, and macular status should be assessed, as it is one of the most important factors influencing visual prognosis.
Investigations
Dilated retinal examination
A detailed dilated retinal examination remains the primary diagnostic investigation.
B-scan ultrasonography
Particularly useful when media opacity prevents visualisation of the retina.
It can identify:
- Retinal detachment
- Vitreous haemorrhage
- Choroidal detachment
Optical coherence tomography (OCT)
OCT helps determine macular status and may identify shallow retinal detachments involving the fovea.
Wide-field retinal imaging
Increasingly used for documentation and surgical planning.
Macula-on and macula-off detachment
Macula-on retinal detachment
The central retina remains attached.
Visual acuity may be preserved, and urgent surgery is performed to prevent foveal involvement.
Macula-Off Retinal Detachment
The fovea has already detached.
Visual prognosis is poorer, and the final visual outcome depends on the duration of macular detachment before surgery.
Management
The goal of treatment is to reattach the retina and close all retinal breaks.
Laser Photocoagulation
Retinal tears without detachment can often be treated using laser photocoagulation.
Laser treatment creates a chorioretinal adhesion around the tear, preventing fluid from entering the subretinal space.
Cryotherapy
Cryotherapy creates a localised inflammatory response and subsequent scar formation around retinal breaks.
Pneumatic Retinopexy
Pneumatic retinopexy involves the injection of an expansile gas bubble into the vitreous cavity.
The gas bubble seals retinal breaks while laser photocoagulation or cryotherapy creates permanent adhesion.
This technique is most suitable for selected superior retinal breaks.
Scleral Buckling
A silicone band is placed around the globe to indent the sclera and relieve vitreoretinal traction.
This supports closure of retinal breaks and promotes retinal reattachment.
Pars Plana Vitrectomy
Pars plana vitrectomy is currently the most commonly performed retinal detachment surgery.
The vitreous gel is removed, traction is relieved, retinal breaks are treated with laser, and internal tamponade is provided using gas or silicone oil.
Internal Tamponades
Common gases include:
- Sulphur hexafluoride (SF₆)
- Perfluoropropane (C₃F₈)
These gases expand after injection and are gradually absorbed over several weeks.
Silicone oil provides longer-term support and is particularly useful in complex retinal detachments.
However, silicone oil often requires a second removal operation.
Patients with intraocular gas must avoid:
- Air travel
- Nitrous oxide anaesthesia
Gas expansion can cause severe elevation of intraocular pressure.
Proliferative Vitreoretinopathy (PVR)
PVR is the most common cause of surgical failure in retinal detachment.
It results from the proliferation of retinal pigment epithelial cells and glial cells, leading to the
formation of contractile membranes.
These membranes cause recurrent traction and retinal re-detachment.
Prognosis
The anatomical success rate of modern retinal detachment surgery 80- 90% in many cases.
Visual outcome depends on:
- Duration of detachment
- Macular involvement
- Presence of proliferative vitreoretinopathy
- Pre-operative visual acuity
Macula-on detachments generally achieve excellent visual outcomes when repaired promptly.
Macula-off detachments often recover useful vision, although vision rarely returns completely to normal.
Complications
Potential complications include:
- Recurrent retinal detachment
- Progression of cataract
- Proliferative vitreoretinopathy
- Raised intraocular pressure
- Epiretinal membrane formation
- Cystoid macular oedema
- Endophthalmitis
In advanced untreated cases, retinal detachment can result in phthisis bulbi and permanent blindness.
Retinal detachment is a sight-threatening ophthalmic emergency that requires early recognition and prompt treatment.
Rhegmatogenous retinal detachment is the most common type and results from retinal breaks associated with vitreoretinal traction.
Modern surgical techniques, including scleral buckling, pneumatic retinopexy, and pars plana vitrectomy, have significantly improved anatomical and visual outcomes.
Early diagnosis and treatment, particularly before macular involvement, remain the most important factors influencing visual prognosis.