Retinal detachment is a serious condition that requires prompt diagnosis and treatment. However, not all detachments are created equal. In this article, we will delve into the classification of retinal detachments and the different types that you may encounter. By understanding the nuances of each type, we can improve our diagnostic and treatment abilities, ultimately leading to better outcomes for our patients. Let’s get started.
1- Rhegmatogenous Retinal Detachment (RRD)
This is the most common type of retinal detachment accounting for about 90% of cases. It occurs when a tear or hole forms in the retina, allowing for fluid to enter and detach the retina from the underlying tissue. Some common causes of RRD include:
- Posterior Vitreous detachment (PVD): This is the most common cause of RRD. A PVD can cause RRD by creating tears in the retina due to the traction exerted on it as the vitreous separates. About 16 percent of acute, symptomatic PVDs present with a retinal break. The average age of PVD is around 60 years old and so this is also the average age for Rhegmatogenous retinal detachment. Although PVD is most often associated with aging, it can occur earlier in patients with certain risk factors such as high myopia, previous eye surgery, or a history of eye trauma.
- Trauma: Any trauma to the eye, such as a blow to the head or face can cause retinal tears and/or detachment.
- Myopia: Patients with high myopia are at a higher risk of developing retinal breaks due to increased prevalence of peripheral retinal thinning and earlier onset of PVD.
- Ocular surgery: Ocular surgeries can induce retinal tears and PVD secondary to changes in fluid dynamics and mechanical forces applied during the procedure.
- Peripheral retinal thinning such as lattice degeneration.
Image description: Rhegmatogenous Retinal Detachment in a patient with visible retinal break (yellow arrow)
2- Tractional Retinal Detachment (TRD):
This type of retinal detachment can occur in virtually any condition that involves pre-retinal neovascularization such as Proliferative Diabetic retinopathy (PDR) which is the most common cause of TRD, Retinopathy of prematurity, Vascular occlusions etc. Neovascularization are abnormal blood vessels that can contract and pull on the retina damaging it. In response to injury, reparative processes such as fibrosis are triggered to restore the damaged tissue. Over time, the formation of fibrosis can contract and further distort and detach the retina. This type of detachment tends to be more gradual and less sudden than other types of retinal detachment.
Image description: Tractional Retinal detachment in a patient with PDR and fibrosis of the posterior pole.
3- Exudative Retinal Detachment:
This type of retinal detachment is less common and occurs when fluid leaks into the subretinal space, separating the retina from the underlying tissue. This can occur in various ocular conditions including Proliferative Age-related macular degeneration which is the most common cause of exudative RD, Central serous chorioretinopathy, Choroidal tumors such as choroidal melanoma, Coats’ disease, Posterior uveitis or other inflammatory disorders such as Vogt-Koyanagi-Harada disease.
Image description: Exudative retinal detachment in a patient with posterior scleritis.
4. Mixed mechanism retinal detachment refers to a type of retinal detachment in which there are elements of both tractional and rhegmatogenous mechanisms involved. In mixed mechanism retinal detachment, there may be a combination of tractional forces pulling on the retina and rhegmatogenous factors leading to fluid accumulation under the retina. This can occur in conditions such as proliferative vitreoretinopathy (PVR), in which scar tissue develops on the surface of the retina, leading to tractional forces, and can also cause retinal tears or holes, leading to rhegmatogenous detachment.