Summary
Normally, the retinal pigment epithelium (RPE) is able to maintain adhesion with the overlying neurosensory retina through the active transport of subretinal fluid across RPE, interdigitation of the photoreceptor outer segments and the RPE microvilli, and it’s own metabolic processes. In retinal detachment, these mechanisms are overwhelmed resulting in separation of the neurosensory (inner layers) retina from the retinal pigment epithelial layer.
Background
This process can occur in three ways:
- Rhegmatogenous retinal detachment: A break in the retina occurs allowing vitreous to directly enter the subretinal space. Often secondary to a retinal tear associated with posterior vitreous detachment or trauma.
- Tractional retinal detachment: Proliferative membranes form on the surface of the retina or vitreous. These membranes can pull on the neurosensory retina causing a physical separation between the neurosensory retina and retinal pigment epithelium
- Exudative retinal detachment: Accumulation of subretinal fluid due to inflammatory mediators or exudation of fluid from a mass lesion.
Clinical presentation
- New onset of flashes and floaters
- Sudden-onset painless, progressive, visual field loss
Risk factors
| Rhegmatogenous |
Tractional |
Exudative |
| Age |
Proliferative diabetic retinopathy |
Inflammatory conditions - eg, uveitis, posterior scleritis. |
| Lattice degeneration |
Penetrating eye injury |
Vascular disease - eg, severe hypertension, Coats' disease. |
| Aphakia |
Retinal vein occlusion |
Toxaemia of pregnancy. |
| Age-related retinoschisis. |
Retinopathy of prematurity |
Congenital abnormalities - eg coloboma |
| Previous retinal break. |
Previous giant retinal tear |
Maculopathy (e.g. wet ARMD) |
| Marfan's syndrome |
Sickle cell retinopathy |
Malignancy (for example, choroidal melanoma or ocular metastasis |
| Previous cataract surgery accelerates PVD |
Toxocariasis |
|
|
Blunt eye trauma |
|
Lattice degeneration
Lattice degeneration is considered the most important peripheral retinal degeneration process predisposing to a rhegmatogenous retinal detachment. It is present in around 10% of the population. It involves the peripheral retina becoming thinned or atrophic in a lattice pattern, resulting in atrophic retinal holes, retinal tears, and retinal detachments. It presents bilaterally and is an important cause of RD in young myopic individuals.
Examination
- Pupillary reflexes
- RAPD may occur if the macula is detached or if at least two quadrants of the non-macular retina have detached
- Visual acuity
- Poor visual acuity suggests macular detachment or a vitreous haemorrhage
- Visual fields
- Confrontational visual field testing may reveal gross visual defects corresponding to the area of detached retina
- Slit lamp examination of the anterior segment
- An important finding with the slit lamp is the presence of 'tobacco dust', this is associated with a 90% risk of a retinal break, which in turn is associated with a vitreous haemorrhage in 70% of cases. The presence of this pigment is known as Schaffer’s sign.
- Rhegmatogenous retinal detachment has a characteristic appearance: a corrugated appearance that undulates with eye movements.
- Tractional detachments have smooth concave surfaces with minimal shifting with eye movements
- Serous detachments show a smooth retinal surface and shifting fluid depending on patient positioning