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Retinal detachment is a complication of the eye in which the layers of the retina become separated, leading to visual deficits and possibly blindness. The retina is located at the back of the eye, and its function is to focus the light that the eye receives, transform this light into nerve impulses, and relay the impulses to the optic nerve. The optic nerve then relays the signals to visual structures in the brain for processing (1). Retinal detachment occurs when the retinal pigment epithelium (RPE) becomes separated from the neurosensory retina, which is the group of nervous and photoreceptor structures that lie above the RPE (1,2) (See Diagram 1).
This separation can occur through several mechanisms; however, all potential mechanisms of injury result in a buildup of fluid in the sub-retinal space. Each different mechanism of injury forms a distinct subtype of retinal detachment, which typically include four main groups (2):
This separation can occur through several mechanisms; however, all potential mechanisms of injury result in a buildup of fluid in the sub-retinal space. Each different mechanism of injury forms a distinct subtype of retinal detachment, which typically include four main groups (2):
- Rhegmatogenous retinal detachment
- Traction retinal detachment
- Exudative or Serous type retinal detachment
- Combined Traction-Rhegmatogenous type retinal detachment.
RhegmatogenousRhegmatogenous retinal detachment involves a break in the retinal tissue spanning the full thickness of the retina. This can be a tear or holes in the retinal tissue. Fluid enters this break in the tissue, and accumulation of fluid separates the neurosensory retina from the retinal pigment epithelium (RPE). In order for this to occur the vitreous gel must be partially or completely liquefied, causing the vitreous body to separate from the retina, and a segment of the separating body must adhere to the retina more than it would in normal circumstances, resulting in enough shear force (called traction) to hold the break in the retina open. Then, the liquefied vitreous fluid enters this tear in the retina, causing detachment (See Diagram 2). Although some traction must be present to maintain the opening in the retina, traction is not the primary cause of the detachment (2).
Combined Traction- RhegmatogenousCombined Traction-Rhegmatogenous type retinal detachment occurs when both traction on and tears/holes in the retinal tissue are present. In this type of retinal detachment traction is the primary cause of detachment, but the traction causes tears, leading to a secondary rhegmatogenous type fluid accumulation (2).
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TractionTraction retinal detachment develops when the neurosensory retina is pulled from the RPE without the development of holes or tears in the retina. This can be caused by shear forces from retinal muscular structures, loss of vitreous fluid, force transmission through other structures that are in contact with the retina, or proliferation of pathologic cell types into the retinal area. (2).
Exudative or SerousExudative or serous type retinal detachment involves fluid accumulation, in the sub-retinal area without any tears, holes, or traction on the retina. The source of this fluid can be either the retinal vasculature, the choroid vasculature (see diagram 3) or a combination of both of these sources. This fluid can also be whole blood in the case of hemorrhage in any of the vasculature. Under normal circumstances the RPE functions as a pump to clear any excess fluid from the sub-retinal space, but if the RPE is damaged, or the fluid accumulation occurs faster than the RPE can disperse the fluid, retinal detachment can occur (2).
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In all cases, detachment of the retinal layers leads to ischemia and atrophy of the neurosensory retinal layers. If the detachment is left untreated neurosensory cell death can occur, resulting in irreversible vision loss (3).
The incidence of retinal detachment in a north American population is 12.6 cases per 100000 population without previous cataract surgery, and 17.9 cases per 100000 population for individuals who are post cataract surgery (3).
Mortality: Retinal detachment on its own does not directly cause mortality, although several of the factors that can lead to the development of retinal detachment are capable of causing mortality.
Morbidity: Retinal detachment can cause visual issues and blindness if not properly treated (3).
Developmental considerations (sex/ age/demographics): Retinal detachment becomes more common with increasing age, and incidence significantly increases in individuals 60 years old or more (3).
*Note:There is no data published regarding gender differences, or exact Canadian epidemiological information. This is an area requiring future research.
The incidence of retinal detachment in a north American population is 12.6 cases per 100000 population without previous cataract surgery, and 17.9 cases per 100000 population for individuals who are post cataract surgery (3).
Mortality: Retinal detachment on its own does not directly cause mortality, although several of the factors that can lead to the development of retinal detachment are capable of causing mortality.
Morbidity: Retinal detachment can cause visual issues and blindness if not properly treated (3).
Developmental considerations (sex/ age/demographics): Retinal detachment becomes more common with increasing age, and incidence significantly increases in individuals 60 years old or more (3).
*Note:There is no data published regarding gender differences, or exact Canadian epidemiological information. This is an area requiring future research.