Causes of Retinal Detachment

There are three main causes of retinal detachment, each with its own set of risk factors. The most common type is called a “rhegmatogenous” detachment, and is caused by a tear or hole in the retina. The retina is the thin, light-sensitive tissue that lines the back inside wall of the eye. If the retina tears, thick liquid called vitreous (which fills the back two-thirds of the hollow eyeball) can seep through the hole. The fluid accumulates underneath the retina, causing the retina to peel away from the back of the eye. Risk factors for rhegmatogenous retinal detachments include aging, cataract surgery, thinning of the outer retina known as lattice degeneration, a high degree of nearsightedness (also called high myopia), and head trauma. Let's look at each one of these causes in more detail:

As we age, our vitreous gradually changes from a thick, gelatin-like consistency to a consistency more like egg white. The vitreous is attached to the retina. As it becomes thinner and moves around more inside the eye, it tugs on the retina and eventually tugs free of the retina. This usually occurs between 55 and 65 years of age. If the vitreous is attached tightly enough to the retina, the separating vitreous can pull a tear in the retina, much like pulling a piece of tape off a piece of paper can rip a hole in the paper.

Cataract surgery involves replacing the large, cloudy human lens inside the eye with a thinner plastic lens implant. This creates extra room inside the eye, like removing some clothes from a tightly packed suitcase. As vitreous flows into the newly created space, it can tug on the retina and occasionally create a retinal tear. Lattice degeneration is the name of a lace-like thinning at the edges of the retina that can make the retina more vulnerable to tears. Nearsightedness of more than 5 diopter powers is associated with a greater risk of retinal tears, possibly because nearsighted eyes are longer than normal and the retina is stretched thinner than normal. It may also be that high nearsightedness is associated with vitreous that is attached to the retina more tightly. A sudden blow to the head or eye, such as hitting a windshield or having an air bag deploy, can also create a tear in the retina. Head trauma is also among the most common causes of retinal detachment in children. Other risk factors for rhegmatogenous detachments include a family history of retinal detachment and certain congenital or hereditary eye diseases.

A less common type of retinal detachment is called a “tractional” detachment. This occurs when vitreous tugs on the retina over time, gradually causing the retina to tent up off the back of the eye. Tractional detachments do not occur suddenly and are not associated with retinal tears. One of the most common causes of tractional detachments is advanced diabetic eye disease in which vitreous grabs onto and tugs on abnormal blood vessels that are growing on the surface of the retina. In children, the most common cause of tractional detachments is a condition called retinopathy of prematurity which can affect premature newborns who receive oxygen in the high-risk neonatal nursery.

The third, even less common type of retinal detachment is called an “exudative” detachment in which fluid leaks out of blood vessels within or underneath the retina. This can occur in inflammatory conditions such as uveitis and scleritis, certain collagen vascular or autoimmune diseases, tumors of the eye, and congenital diseases such as Coat's disease.

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