A ring-shaped disturbance in your vision can come from several different parts of the eye or brain, and the cause ranges from completely harmless to urgently serious. The single most common reason is a Weiss ring, a circular floater that appears after the gel inside the eye pulls away from the retina. But rings, arcs, and halos can also stem from migraine aura, lens changes, prior eye surgery, retinal disease, and even certain medications. What the ring looks like, when it appears, and whether it moves with your gaze all help narrow the cause.
The Weiss Ring and Posterior Vitreous Detachment
The vitreous is a clear, jelly-like substance that fills the space between your lens and your retina. It is attached to the retina at several points, and the strongest attachment is around the optic nerve head at the back of the eye. As you age, the vitreous gradually shrinks and liquefies. At some point, often after age 50, it peels away from the retina entirely. This event is called a posterior vitreous detachment, or PVD, and it happens to most people eventually.
When the vitreous detaches from around the optic nerve head, it often pulls a small ring of tissue with it. That ring, called a Weiss ring, floats freely in the vitreous cavity and casts a shadow on your retina. You see it as a translucent, roughly circular floater, sometimes described as a cobweb, a loop, or a hazy doughnut shape. It drifts when you move your eyes and tends to be most noticeable against bright, uniform backgrounds like a white wall or blue sky. In many people it settles lower in the eye over weeks to months and becomes less bothersome, though it does not truly disappear.
A PVD by itself is not dangerous. The concern is what can happen during the detachment process. As the vitreous pulls away, it can tug hard enough on the retina to tear it, and a retinal tear left untreated can progress to a retinal detachment, which threatens permanent vision loss. A study tracking patients referred with PVD symptoms found that those who went on to develop a retinal tear or detachment were significantly more likely to report blurred or missing areas of vision compared to those with an uncomplicated PVD alone.1PubMed Central. Posterior vitreous detachment and retinal tear – a prospective study of community referrals Flashes of light, a sudden shower of new floaters, or a curtain-like shadow creeping across your vision are all red flags that the detachment may have caused a tear.
Migraine Aura and Scintillating Arcs
If the ring you see is a shimmering, jagged arc of light that expands outward over 15 to 30 minutes and then fades, the most likely explanation is migraine with aura. Unlike a floater, a migraine arc stays fixed in the same spot in your visual field regardless of where you look, because the disturbance is happening in the brain rather than inside the eye.
The phenomenon behind migraine aura is a slow wave of electrical and chemical activity that rolls across the visual cortex at the back of the brain. This wave, called cortical spreading depression, temporarily disrupts normal nerve cell firing. Intracranial recordings in a patient experiencing migraine with aura captured the wave starting in the occipital cortex and propagating forward at roughly 3 millimeters per minute, matching the expanding visual disturbance the patient reported in the opposite visual field.2PubMed. Mapping the migraine: Intracranial recording of cortical spreading depression in migraine with aura Mathematical models of this spreading wave reproduce the classic zigzag arcs and expanding crescents that migraine sufferers describe.3PubMed Central. Migraine Visual Aura and Cortical Spreading Depression-Linking Mathematical Models to Empirical Evidence
Migraine aura does not always come with a headache. Some people get the visual disturbance on its own, especially later in life. This “silent migraine” or acephalgic migraine is benign but can be alarming if you have never experienced it before. The key features that point toward migraine rather than an eye problem are the expansion of the arc over many minutes, the zigzag or fortification-pattern edges, and the fact that closing one eye does not make the ring disappear since both eyes share the same visual cortex.
Halos Around Lights
Rings that show up specifically around light sources, like oncoming headlights or streetlamps, are halos, and they have a different set of causes. Some degree of halo effect is normal, especially at night when your pupils are wide open. But prominent or worsening halos usually point to something scattering or bending light before it reaches your retina cleanly.
Cataracts and Lens Clouding
The most common culprit in people over 60 is a cataract. As the natural lens of the eye becomes cloudy, it diffracts incoming light into concentric rings. Early cataracts often cause halos that are most obvious at night, long before daytime vision feels affected. The type and location of the cataract influence how bad the halos get. Nuclear cataracts, the kind that forms in the center of the lens, tend to produce a diffuse glow, while cortical cataracts, which grow in spoke-like wedges from the edge, scatter light in more distinct ring patterns.
Post-Surgical Rings and Glare
Cataract surgery replaces the cloudy lens with an artificial one, which usually eliminates the old halos. But the new lens can introduce its own unwanted light effects, called dysphotopsias. Patients describe these as glare, light streaks, starbursts, arcs, rings, or flashes of light.4PubMed Central. Dysphotopsias or Unwanted Visual Phenomena after Cataract Surgery Multifocal intraocular lenses, designed to reduce dependence on reading glasses by splitting light into multiple focal points, are especially prone to producing ring-shaped halos around lights. Some patients find them bothersome enough to seek lens exchange.5PubMed Central. Monofocal intraocular lens with enhanced intermediate function as substitute for multifocal intraocular lens in positive dysphotopsia For many people, though, these optical artifacts fade as the brain adapts over weeks to months.
Post-LASIK Halos
Laser vision correction can produce a similar issue. After LASIK, the reshaped corneal surface introduces higher-order optical aberrations, tiny irregularities that scatter light. A study measuring halo perception before and after successful LASIK found that the halo disturbance index roughly doubled after surgery, and the strongest predictors of that increase were spherical aberration and coma in the cornea.6PubMed Central. Night vision disturbances after successful LASIK surgery These halos are typically most noticeable at night and tend to improve over the first six to twelve months as the cornea heals and the brain recalibrates. In a minority of patients, however, persistent nighttime halos remain a lasting trade-off of the procedure.
Ring Scotoma From Retinal Disease
A scotoma is a blind or dim spot in the visual field, and when it takes a ring shape it usually signals disease in the peripheral retina. The most recognized cause is retinitis pigmentosa, a group of inherited conditions in which the photoreceptor cells gradually die. The classic progression starts with patchy loss of peripheral vision that coalesces over years into a ring-shaped blind zone surrounding the central field, producing what is often called tunnel vision.7PubMed Central. Visual Field Progression in Retinitis Pigmentosa People in the mid-stages sometimes describe this as a dark ring or annular shadow that blocks the mid-peripheral view while central and far-peripheral vision remain relatively intact.
A ring scotoma feels different from a floater or a halo because it is an absence of vision rather than an addition. You do not see a floating shape or a bright glow. Instead, there is a zone where objects simply vanish. Early on, the brain fills in the missing area so effectively that many people do not notice it until formal visual field testing reveals the loss. Night blindness is usually the first symptom people recognize, sometimes years before the ring scotoma becomes obvious.
Solar Retinopathy and Light Damage
Staring at the sun, even briefly during an eclipse, can burn a small area of the retina at the fovea, the pinpoint center of sharpest vision. The injury, called solar retinopathy, typically leaves a small central or paracentral scotoma: a dim, dark, or distorted spot right where you are trying to focus. Some people describe this as a ring-like afterimage that refuses to fade.
Imaging of patients with solar retinopathy shows damage concentrated in the outer layers of the retina, particularly the ellipsoid zone and the interdigitation zone, the structures where photoreceptor cells convert light into signals.8PubMed Central. Swept-Source Optical Coherence Tomography and Optical Coherence Tomography Angiography Findings in Patients with Solar Retinopathy In mild cases the damage heals on its own over weeks to months and the scotoma shrinks or disappears. In severe cases the photoreceptors do not regenerate, and a permanent blind spot remains. There is no reliable treatment once the burn has occurred, which is why eclipse glasses and proper solar filters matter so much.
Medication Side Effects That Alter Vision
Certain drugs can change the way light is processed and produce ring-like or halo-like disturbances. Digoxin, a heart medication, is one of the classic examples. At toxic levels, digoxin disrupts the sodium-potassium pumps in retinal photoreceptors, altering color perception and producing visual symptoms. The most famous is xanthopsia, a yellow-tinted overlay on everything, but halos around lights and blurred vision also occur. A case report described a patient whose digoxin dose was doubled, pushing his blood level well above the therapeutic range, who developed xanthopsia severe enough to cause traffic accidents before he stopped driving.9PubMed Central. Xanthopsia Due to Digoxin Toxicity as a Cause of Traffic Accidents: A Case Report
Other medications linked to halos or ring-like visual symptoms include some glaucoma eye drops, certain antidepressants, and sildenafil (Viagra), which can transiently affect color vision and produce a blue-tinted halo at higher doses. If a new ring or halo in your vision coincides with starting or adjusting a medication, that timing is worth mentioning to your doctor. Drug-induced visual changes are almost always reversible once the medication is adjusted or stopped.
Entoptic Phenomena and Seeing Your Own Eye
Sometimes a ring in your vision is literally the shadow of a structure inside your own eye. These are called entoptic phenomena, and they have fascinated researchers since the early 1800s. The best-known entoptic image is the shadow of your retinal blood vessels, which you can sometimes see by shining a penlight from the side of your eye and wiggling it gently. The vessels appear as a branching tree pattern, momentarily visible before the brain adapts and filters them out again. This observation was first reported in 1819 and was later used to deduce the location of the retina’s light-sensitive layer, a conclusion that still holds.10PubMed. The entoptic view of the retinal vessels
Other entoptic images include the blue field entoptic phenomenon, where tiny bright dots zip around in your vision when you look at a clear blue sky. Those dots are white blood cells moving through the capillaries in front of your retina. While these observations are not specifically ring-shaped, they illustrate a broader point: not everything you see in your vision corresponds to something outside your body. Your visual system is full of its own internal anatomy, and under the right lighting conditions, some of it becomes visible. The Weiss ring from a PVD is arguably the most ring-specific entoptic image, since it is a literal physical ring casting a shadow on the retina.
How to Tell the Causes Apart
Given how many things can produce a ring in your vision, it helps to ask yourself a few questions when deciding how worried to be:
- Does it move? A floater or Weiss ring drifts with your eye movements and then settles. A scotoma stays locked in one spot relative to where you look. A migraine arc expands and evolves over minutes.
- When does it appear? Halos around light sources that are worst at night point toward the cornea or lens. A ring visible all the time, including in daylight, points toward the vitreous or retina.
- Is it bright or dark? A bright shimmering arc is more likely a migraine or a positive dysphotopsia. A dark ring or missing area is more likely a scotoma from retinal disease.
- How quickly did it start? A sudden onset over hours suggests PVD, retinal tear, or migraine. A gradual onset over months to years suggests cataract, retinitis pigmentosa, or another degenerative process.
- Does closing one eye help? If the ring disappears when you close one eye, the problem is in the open eye. If it persists with either eye open, the cause is likely neurological.
None of these rules are absolute, but they give you a starting framework. Any new, persistent, or worsening visual disturbance deserves a dilated eye examination, because the most important step is ruling out retinal tears and retinal detachment.
Treating a Persistent Weiss Ring
Most floaters, including the Weiss ring, become less noticeable over time as the brain learns to ignore them. For people who find a Weiss ring genuinely disabling, though, there are treatment options. The least invasive is YAG laser vitreolysis, where a laser is aimed at the floating ring to break it into smaller, less visible pieces. A study following patients for about two years after YAG vitreolysis of Weiss ring floaters found that half felt their symptoms were significantly or completely better, with an overall symptom improvement of roughly 60 percent. However, three eyes in that cohort developed delayed retinal tears between one and three years after the procedure.11PubMed. Long-Term Follow-Up of Efficacy and Safety of YAG Vitreolysis for Symptomatic Weiss Ring Floaters Another study found that YAG treatment of the Weiss ring produced a statistically significant improvement in visual function questionnaire scores, though some patients experienced temporary blurring.12Pakistan Journal of Ophthalmology. Nd: YAG laser of Weiss Ring for the Treatment of Symptomatic Vitreous Floaters in Patients with Posterior Vitreous Detachment
The more definitive procedure is a vitrectomy, surgery to remove the vitreous entirely and replace it with saline. Vitrectomy eliminates floaters completely but carries higher risks, including cataract formation and, rarely, retinal detachment. Most ophthalmologists reserve it for severe cases where floaters substantially impair daily activities and laser treatment has not helped. The risk-benefit calculation is personal: a barely noticeable ring in a retired person’s vision is a very different problem from a prominent ring in the central vision of someone who drives for a living.
When Children See Rings
Ring-shaped visual complaints in children are uncommon, but they do happen. Migraine with aura can begin in childhood or adolescence, and younger patients sometimes struggle to describe what they see, calling it a “shiny circle” or a “weird ring” rather than the classic zigzag crescent adults report. PVD is rare in children unless they have had eye trauma, surgery, or severe nearsightedness, so a new floater ring in a child’s vision warrants prompt evaluation.
Children are also more susceptible to solar retinopathy because they are more likely to stare at the sun out of curiosity, and the lens of a young eye transmits more ultraviolet and short-wavelength light than an older, yellowed lens. A child who complains of a persistent spot or ring after looking at the sun should be examined, even if they seem fine otherwise. The good news is that younger retinas tend to recover more completely from mild solar burns than older ones.