Retinal detachment happens when the thin layer of tissue lining the back of your eye pulls away from its normal position, separating from the blood supply it needs to function. It affects roughly 12 out of every 100,000 people per year worldwide, and it’s considered a medical emergency because delayed treatment raises the risk of permanent vision loss. The causes range from age-related changes inside the eye to trauma, diabetes, and inflammatory diseases.
How the Retina Normally Stays in Place
Your retina sits against the back wall of your eye, held in position partly by the gel-like substance that fills the eyeball, called the vitreous. The retina is nourished by a layer of tissue underneath it. When anything disrupts the bond between the retina and that underlying layer, whether it’s a tear, a pulling force, or a buildup of fluid, the retina can peel away and stop working properly.
The Three Types and Their Causes
Rhegmatogenous Detachment
This is the most common type. It starts with a tear or hole in the retina. Once a break forms, the vitreous gel seeps through the opening and collects behind the retina, gradually pushing it away from the back of the eye. The tear itself usually results from changes in the vitreous that happen with age. Over time, the vitreous gel liquefies and its collagen fibers clump together (those clumps are what you see as floaters). Eventually the vitreous shrinks enough to pull away from the retina entirely, a process called posterior vitreous detachment. In most people this separation is harmless. But if the vitreous tugs on a spot where it’s firmly stuck to the retina, it can rip a hole, and that hole becomes the entry point for fluid.
Tractional Detachment
Instead of a tear, scar tissue on the retina’s surface physically pulls the retina off the back wall. This is the type most associated with advanced diabetes. When blood sugar remains high over years, small blood vessels in the retina close off and the tissue becomes starved of oxygen. The eye responds by growing new, fragile blood vessels that extend into the vitreous cavity. Supportive cells then surround those vessels and form bands of fibrous tissue. As the fibrous tissue contracts, it drags the retina forward. The pulling typically happens along the major blood vessel pathways near the center of the retina and can eventually form a ring of traction around the area responsible for sharp central vision.
Exudative Detachment
In this type there’s no tear and no scar tissue. Fluid simply leaks into the space behind the retina faster than the eye can drain it. The fluid accumulation pushes the retina forward. This can result from inflammation, infection, tumors inside the eye, or vascular problems that break down the barrier between the bloodstream and the retina. Conditions linked to exudative detachment include Vogt-Koyanagi-Harada syndrome (an autoimmune disease affecting pigmented tissues), posterior scleritis, sarcoidosis, Behçet disease, choroidal melanoma, retinoblastoma, and metastatic cancers that spread to the eye.
Age-Related Changes
The single most common pathway to retinal detachment is the natural aging of the vitreous gel. In younger eyes the vitreous is thick and firmly attached to the retina at several points. Starting in middle age, the gel gradually liquefies and its structural fibers collapse. This process accelerates after age 50. When the vitreous finally separates from the retina, the sudden release can tear fragile retinal tissue, especially at the periphery where the retina is thinnest. Most people who experience a posterior vitreous detachment notice a burst of new floaters and brief flashes of light but never develop a tear. The danger is in the small percentage of cases where the separation isn’t clean.
Nearsightedness and Structural Weakness
People with moderate to high myopia (roughly negative 6 diopters or more) face a significantly elevated risk. Their eyeballs are physically longer than average, which stretches the retina thinner across a larger surface area. That stretch also promotes weak spots in the peripheral retina called lattice degeneration, patches where the retina is abnormally thin and prone to tearing. Studies have found lattice degeneration in about 24% of highly myopic eyes, compared to around 6% in the general myopic population. Eyes with peripheral retinal abnormalities also tend to be more severely nearsighted. Because the retina is already under tension, it takes less force from a shrinking vitreous to create a tear.
Eye Surgery and Procedures
Cataract surgery is the most common intraocular procedure worldwide, and it modestly raises the risk of retinal detachment afterward. A pooled analysis estimated the risk at roughly 1.2%, compared to about 0.08% in the general population. The increase happens because removing the natural lens changes the vitreous environment inside the eye, accelerating vitreous shrinkage and separation. The risk is highest in the first year or two after surgery but can persist for several years. People who are already nearsighted before cataract surgery carry the greatest added risk.
Eye Trauma
A blow to the eye, whether from a ball, a fist, or a fall, can cause immediate or delayed retinal detachment. Traumatic detachments account for an estimated 10% to 40% of all cases and are far more common after blunt injuries than penetrating ones. The force of impact compresses the eyeball, creating shearing stress at the retina’s edges that can produce tears or a specific injury pattern called retinal dialysis, where the retina pulls away at its outer border. One important detail: traumatic detachments don’t always show up right away. They can develop months or even years after the original injury as scar tissue slowly contracts. Young men are disproportionately affected, partly because they sustain the majority of sports-related eye injuries.
Diabetes and Vascular Disease
Proliferative diabetic retinopathy is the leading cause of tractional retinal detachment. The process begins with chronically high blood sugar damaging the smallest blood vessels in the retina. As those vessels close off, the retina releases signaling molecules that trigger new blood vessel growth. These new vessels are fragile, leak easily, and grow along the surface of the vitreous gel like vines on a trellis. Over time, the fibrous tissue that forms around them tightens and pulls the retina away from the wall of the eye. Interestingly, if the vitreous separates from the optic nerve head completely on its own, it actually removes the scaffold those new vessels need to grow, which can reduce the chance of progression to the most dangerous stage of the disease.
Inflammation and Immune Conditions
Chronic inflammation inside the eye can cause retinal detachment through two pathways. First, ongoing inflammation promotes cell growth and scarring within the vitreous, which can create traction on the retina similar to what happens in diabetes. Second, inflammation can break down the barrier that normally keeps blood plasma out of the space behind the retina, leading to exudative fluid buildup. Autoimmune conditions like Vogt-Koyanagi-Harada syndrome, sarcoidosis, and inflammatory bowel disease are all recognized triggers. Even localized inflammation of the white outer coat of the eye (posterior scleritis) can generate enough fluid leakage to lift the retina off.
Warning Signs to Recognize
Retinal detachment often announces itself with a cluster of sudden symptoms: a dramatic increase in floaters, flashes of light in one or both eyes, and a shadow or curtain creeping across your field of vision. The floaters may look like a shower of tiny dark spots or squiggly lines, noticeably different from the one or two floaters most people see from time to time. Flashes of light happen because the retina responds to any mechanical pulling the same way it responds to light, by firing signals to the brain. If only a small area of retina has separated, you might not notice anything at all, which is why routine eye exams matter for people with known risk factors.
Why Early Treatment Changes the Outcome
The part of the retina that matters most for sharp, detailed vision is the macula, a small area at the center. Whether the macula is still attached at the time of repair is the single biggest predictor of long-term visual recovery. A 10-year follow-up study from Scotland found that 93% of patients whose macula was still attached at the time of surgery maintained vision good enough to meet the UK driving standard a decade later. When the macula had already detached before repair, that number dropped to 65%. Median long-term visual acuity was near-perfect in the macula-on group and measurably reduced in the macula-off group. This gap persisted for the full 10 years of the study, reinforcing that the hours and days between first symptoms and surgical repair have lasting consequences.