When it comes to parts of your eyeball, you generally don’t want things to detach. Usually, attached is a better situation. It would be an ideal scenario if your eyelashes were to remain attached to your eyelid, and for your crystalline lens inside the eye to stay attached to the ciliary muscles that control how it focuses on near objects. Likewise, you probably want your retina to be attached to the wall of the eyeball because if it isn’t, it makes it difficult to see.
What is the Retina?
Before we get ahead of ourselves explaining how the retina detaches, let’s first find out what the retina even is.
The retina is a layer (actually, technically ten layers) of tissue. It lines the back of the eyeball and is made up of a complex network of neurons and supporting cells with names such as ganglion cells, rods, cones, bipolar cells, and horizontal cells. When light hits the rod and cone photoreceptors of the retina, this triggers a cascade of electrical signals that run through the layers of retina, through the optic nerve, and all the way to the visual areas of the brain. This results in visual perception and the ability to see the world around you.
The outer retina, which includes the photoreceptor layer, receives its oxygen and nutrients from a blood vessel-rich tissue called the choroid. This blood supply from the choroid accounts for about 85% of the circulation within the eyeball, making it a fairly important piece of anatomy. The inner retina is fed by the central retinal artery and its various branches. Between the choroid and the neurosensory layers of the retina lies the retinal pigment epithelium (RPE). This layer of tissue is responsible for controlling the movement of fluid and other substances between the retina and choroid circulation. The RPE also protects the neurosensory retina from oxidative damage.
During a retinal detachment, the neurosensory retinal tissue comes away from the underlying layers, including the retinal pigment epithelium, the choroid, and all the vital oxygen, nutrients, and metabolic support these tissues are supplying for the retina to function. In short, this is bad.
What Causes a Retinal Detachment
There are three categories of retinal detachment, which describe the basic cause of the retina separating from the eye. These include:
- Rhegmatogenous retinal detachments, which involve a hole or tear in the retina allowing fluid to accumulate beneath it. The build-up of fluid can cause the retina to separate from the underlying tissues.
- Tractional retinal detachments occur due to some sort of pulling (tractional) force on the retina. This can be from the development of retinal scarring or inflammation.
- Exudative retinal detachments, like rhegmatogenous causes, involve the accumulation of fluid beneath the retina. However, there is no hole or tear in the retina. Instead, fluid develops beneath the retinal layers for some other reason, such as from inflammation or leaky blood vessels.
Various eye diseases can be associated with causing a retinal detachment though detachments are also known to occur with no identifiable cause, a situation called an idiopathic retinal detachment. Eye conditions that can be linked to an increased risk of retinal detachments include diabetic retinopathy, lattice degeneration (thinning of the peripheral retina), uveitis (inflammation of parts of the eye), near-sightedness (also known as short-sightedness or myopia). Trauma and complications of eye surgery for other conditions (such as cataracts) are also known to cause a retinal detachment.
In addition to these causes of a retinal detachment, your overall risk also increases with older age, if you’ve previously had a retinal detachment, or if a family member has suffered a retinal detachment.
Symptoms of a Retinal Detachment
Small detachments, particularly in the far periphery of the retina where you’re less attentive, may go unnoticed. Symptomatic retinal detachments are commonly associated with:
- Sudden floaters, which appear as dark specks, squiggles, or cobweb-like shadows
- Flashing lights, often in the periphery of your vision
- A dark curtain or shadow across part of your vision
- Blurred vision
Retinal detachments may involve the macula or be macula-sparing. The macula is the specialized part of the retina that is responsible for your central vision. If a retinal detachment involves the macula, you will have trouble reading, driving, and recognizing faces – anything that requires seeing fine detail.
A retinal detachment is never painful (though the trauma that caused it may be). Your eye will look entirely normal from the outside while a detachment is taking place, but inside is a time-sensitive emergency.
Posterior Vitreous Detachment
While attached is typically better than detached, a natural part of aging is a process called a posterior vitreous detachment (PVD). It’s worth mentioning PVDs here as their symptoms can often mimic a retinal detachment, and they can also be a risk for an actual retinal detachment (and which is why increasing age is a risk factor for retinal detachments).
The vitreous is a gel filling the back of the eyeball, adhered to certain points around the retina. As your eye (and face it, the rest of you, too) gets older, the vitreous begins to liquefy. As the vitreous loses its solid gel structure, it can tug on those points of adhesion around the retina. If these points are unable to come away cleanly, it can cause a retinal tear and/or a retinal detachment.
The common symptoms of a PVD are floaters and flashes, which are much the same as what you might expect to see during a retinal detachment. Although the actual PVD itself is normal and harmless, it increases your risk of an actual detachment in the following weeks so any new floaters and flashes should always be checked.
Treatment for a Retinal Detachment
As far as urgent eye emergencies go, retinal detachments are up there. A detached retina that is left for too long can result in permanent vision loss.
A retinal detachment can be diagnosed by either an optometrist or ophthalmologist (eye doctor), however, only an ophthalmologist is qualified to treat it. In order to diagnose a detachment, your eyecare professional will instill eyedrops to widen the pupil (the hole in the middle of your colored iris) to get a good look inside at the retina.
To treat a retinal detachment, the ophthalmologist may use one or a combination of surgical techniques, depending on factors such as the location and size of the detachment.
- Pneumatic retinopexy involves injecting a bubble of gas into the back of the eye. As the gas rises and expands, it pushes the retina back against the wall of the eye, so the surgeon can then use a freezing probe or laser to weld the retina into place.
- Scleral buckling involves surgically stitching a silicone band around the outside of the eyeball (the sclera). This presses the wall of the eye inward so the surgeon can apply the freezing probe or laser to stick the retina back to the eye. In the case of a tractional detachment, scleral buckling can also help to relieve some of the pressure pulling against the retina.
- A vitrectomy involves surgically removing the vitreous gel from the eye. It’s useful if the retinal detachment involves traction as removing the vitreous can also remove whatever is causing the traction.
Your vision may take some time to return to normal even after timely surgery. In some cases, the vision cannot be fully restored.
People with risk factors for retinal detachment, such as previous eye trauma or high short-sightedness, may be recommended to have regular dilated eye exams. These exams involve administering those eyedrops to widen the pupil, allowing your eye-care clinician to check your retina for any signs of an impending detachment. Retinal holes and tears can be proactively treated to prevent them from progressing into a detachment if they’re deemed to be high-risk, so it’s worthwhile turning up for these eye exams even if you haven’t noticed any symptoms of a detachment.
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