A grey spot in the eye falls into one of two groups: a spot you see in your vision, or a mark that someone can see on the surface of your eye. The two have different causes, so the first step is working out which one you have. Most of these spots are harmless, but a few vision changes are emergencies where acting within hours can protect your sight.
Is It in Your Vision or on Your Eye
A grey or brown patch that you or other people can see in the mirror sits on the white of the eye or on the coloured iris. A spot on the surface usually does not change what you see, while a spot in your vision usually does.
You can sort this out at home in a few minutes. Look at a plain bright wall or the sky and note whether the spot drifts or stays fixed. Cover one eye at a time to learn whether one eye or both see it. Then check the mirror in good light, and photograph any visible mark so you can compare it later. Note when the spot started and whether it came on suddenly.
If you see the spot with either eye covered, the cause may be the brain rather than the eye. A migraine aura is one common example, covered later.
How the spot behaves tells you more than its colour. Floaters are shadows cast inside the eye, so they swing and lag behind when your eye moves, then settle slowly. A spot pinned to one place in your view however you move your eye is a different kind of problem and worth an exam. A mark in the mirror does not rule out a separate problem in your vision.
Floaters Are the Most Common Grey Spots in Vision
The inside of the eye is filled with a clear jelly. With age it liquefies and shrinks, and tiny collagen fibres in it clump together.1Mayo Clinic. Eye floaters These clumps cast small shadows on the retina, the light-sensing layer at the back of the eye, and you see those shadows as floaters.2Mayo Clinic. Eye floaters Floaters are especially common in nearsighted people.3PubMed. Vitreous floaters: Etiology, diagnostics, and management
Floaters can look like grey dots, threads, rings, or cobwebs. They drift away when you try to look straight at them. Many people find the brain learns to ignore them over months.
As the eye’s gel shrinks, it usually peels away from the back of the eye, where it is attached to the retina in places. This is common in later adult life and often painless. Floaters can seem to appear overnight even though the gel has been changing for years, because you notice them only when a clump drifts into your line of sight. Long-standing floaters that look the same week to week are usually part of normal ageing.
Floaters are not a stain or growth on the eye, so drops, supplements, or eye exercises will not dissolve them. Moving your eyes up and down can shift a floater out of the way, and sunglasses and less glare make them less noticeable. Mention them at your next routine eye exam so a baseline is recorded.
When a Grey Spot Is an Emergency
- A sudden burst of many new floaters, dots, squiggles or cobwebs.4Clearview Eye and Laser Medical Center. Eye Emergency? ER vs. Urgent Care vs. Eye Doctor
- Flashes of light, especially if they appear suddenly or increase.5Austin Retina Blog. Save Your Vision Month: 7 Retina Red Flags You Should Not Ignore
- A dark shadow or curtain on the side or in the middle of your vision.6National Eye Institute. Retinal Detachment
- Sudden loss of vision in one eye.7Austin Retina Blog. Save Your Vision Month: 7 Retina Red Flags You Should Not Ignore
These signs can mean the retina has torn, often because the ageing gel pulled on it.8PubMed Central. Rhegmatogenous Retinal Detachment—an Ophthalmologic Emergency A retinal detachment is when the retina separates from the back of the eye and its blood supply.9Clearview Eye and Laser Medical Center. Eye Emergency? ER vs. Urgent Care vs. Eye Doctor Without oxygen and nutrients the retinal cells die quickly, and vision can be lost permanently if the retina isn’t reattached soon.10Clearview Eye and Laser Medical Center. Eye Emergency? ER vs. Urgent Care vs. Eye Doctor An increase in floaters can also mean bleeding inside the eye.11Austin Retina Blog. Save Your Vision Month: 7 Retina Red Flags You Should Not Ignore Any of these signs calls for an eye exam the same day.
A tear is usually painless. The retina has no pain sensors, so you can’t rely on discomfort to tell you something is wrong; the warning comes from changes in how you see. Flashes are often described as camera flashes or lightning streaks, most noticeable in dim light or at the edge of vision. They come from the gel tugging on the retina, which the brain reads as light. A shadow often starts in the outer part of your vision and creeps inward over hours or days. If it is spreading, you need to be seen the same day rather than at the next available appointment.
Call your eye doctor first and say you have new flashes or a curtain over your vision. If they cannot see you today, an emergency department or urgent eye clinic is appropriate. Don’t wait for the weekend to pass, and don’t drive if your vision is impaired.
A Fixed Grey Spot in the Centre of Vision
Unlike a floater, a central spot does not drift when the eye moves. It sits exactly where you look, blocking words or faces, and it often comes with distortion or dimmed colours. An Amsler grid, or simply checking a door frame for wavy lines, can reveal it.
Central serous chorioretinopathy is a condition where fluid collects under the centre of the retina.12PubMed Central. Central Serous Chorioretinopathy It usually affects one eye and shows up as a dark spot in the middle of vision, with things looking smaller or bent.13PubMed. Central serous chorioretinopathy Straight lines looking wavy alongside a central spot is a reason to book an exam promptly.
In advanced age-related macular degeneration, damaged tissue can leave a fixed blind spot in the centre of vision.14PubMed Central. Long-term follow-up of fixation patterns in eyes with central scotomas from geographic atrophy that is associated with age-related macular degeneration People learn to look slightly off-centre to read and recognise faces.15PubMed Central. Long-term follow-up of fixation patterns in eyes with central scotomas from geographic atrophy that is associated with age-related macular degeneration
Optic neuritis, inflammation of the optic nerve, can cause a blurry or dark spot in the middle of vision, often within hours.16Eye & Ear Foundation of Pittsburgh. Optic Neuritis: Symptoms, Causes, and Treatments Some people describe it as looking through a grey film.17Vasan Eye Care. What Is Optic Neuritis? Symptoms & Recovery Guide Rapidly blurring central vision in one eye, especially with eye pain on movement, needs urgent review.
Checking each eye alone matters, because the brain fills in gaps when both eyes are open. A central problem in one eye can go unnoticed for a long time until you cover the good eye.
Shimmering Grey Spots From Migraine
A typical migraine aura starts as a small greyish spot near the centre of vision.18PubMed Central. Visual Perception in Migraine: A Narrative Review It grows outward into flickering, zigzag lines and leaves a temporary blind patch behind.19PubMed Central. Visual Perception in Migraine: A Narrative Review The cause is a slow wave of changed brain activity moving across the part of the brain that handles vision.20PubMed Central. Neuro-ophthalmology and migraine: visual aura and its neural basis So the aura appears in the same area whichever eye you cover, since it comes from the brain and not the eye.21PubMed Central. Visual Perception in Migraine: A Narrative Review
An aura typically builds over several minutes, spreads, and then fades over roughly the same time, often within an hour. A spot that appears instantly and stays the same is less typical. The shimmering edge often looks like a C-shaped zigzag that expands toward the side of vision, and many people see it with their eyes closed as well as open, which points to the brain rather than the eye.
A headache may follow, but aura can happen without any headache, even in people who never get headaches. A painless shimmering spot can still be migraine, though that is a diagnosis for a doctor to make. A shadow that stays or spreads in one eye is not aura and needs urgent care. A first-ever aura, especially after age 50, should be checked by a doctor.
A Grey or Brown Mark on the White or Coloured Part
A conjunctival nevus is a mole-like spot on the clear film covering the white of the eye, and it is very common.22American Academy of Ophthalmology. Nevus (Eye Freckle) It ranges from yellow to brown, can lighten or darken over time, and is usually not cancerous.23American Academy of Ophthalmology. Nevus (Eye Freckle) A freckle on that film can move slightly when the film is gently shifted, because it lies on the surface, and it often looks brown or yellowish and a little raised.
Grey or brown patches on the white of the eye can be scleral melanocytosis, extra pigment in the eye wall.24HealthTap. There is a dark grey irregular shaped spot on the white portion of my baby girl’s eyeball (8 months old), what’s that? It is not harmful, and any treatment is cosmetic.25HealthTap. There is a dark grey irregular shaped spot on the white portion of my baby girl’s eyeball (8 months old), what’s that? These flat grey patches lie deeper than the surface film, showing through it.26PubMed Central. Conjunctival Nevus They tend to look slate grey or bluish and do not move when the film is shifted. That difference is a clue, not a test. Only an eye doctor with a microscope can tell with confidence which kind you have.
Dark spots on the coloured iris are usually freckles or larger nevi, which are typically benign.27American Academy of Ophthalmology. Nevus (Eye Freckle) Iris nevi can slowly grow larger over time.28American Academy of Ophthalmology. Nevus (Eye Freckle) Having a doctor photograph and measure a spot gives a baseline for spotting real change. You can keep your own record too: take a clear photo in the same lighting every few months and bring the photos to your eye exam.
When a Spot Could Be Eye Melanoma
Uveal melanoma is a rare cancer of the pigment cells in the eye’s middle layer.29Melanoma Research Alliance. Uveal Melanoma (Eye Melanoma): Signs & Care About 90% start in the choroid at the back of the eye, and only about 4% in the iris.30Melanoma Research Alliance. Uveal Melanoma (Eye Melanoma): Signs & Care So most eye melanomas are not visible in a mirror and are found during eye exams. A person can have one with no mark showing, which is why a clean-looking eye does not rule it out.
Warning signs include a dark iris spot that gets bigger, a change in pupil shape, and blurred vision in one eye.31Melanoma Research Alliance. Uveal Melanoma (Eye Melanoma): Signs & Care Floaters, flashes, loss of side vision, or eye bulging can occur as the tumour grows.32Winship Cancer Institute of Emory University. Ocular Melanoma Symptoms A spot that is growing or changing shape should be seen by an eye doctor within weeks.
Benign freckles far outnumber melanomas, and a spot unchanged for years is reassuring. Many melanomas are found by chance at a routine dilated exam, before they cause symptoms, which is the main argument for keeping up regular eye checks.
Doctors look for a thick or raised spot, one that is growing, or one with fluid beneath it, measuring size and thickness with photographs and scans. They often watch a small suspicious spot over time instead of treating it immediately, since many turn out to be benign nevi. If a spot is judged likely to be melanoma, a specialist in eye tumours will usually plan treatment, which often aims to save the eye.
Less Common Causes of a Grey Haze or Spot
Scars or swelling on the cornea, the clear front window, can leave a cloudy grey spot.33Wikipedia. Corneal opacity With age, the lens can slowly yellow and brown into a cataract, which dims and greys vision.34PubMed Central. The ageing lens and cataract: a model of normal and pathological ageing Some infections, such as toxoplasmosis, can leave grey-white spots deep in the retina in young adults.35PubMed Central. The Eye as a Window to Systemic Infectious Diseases: Old Enemies, New Imaging
A cataract greys the whole view rather than adding a moving dot. It often makes headlight glare worse and colours look duller or yellower. A corneal scar may be visible on the eye and blur vision in one area. Either one can affect just one eye, so covering each eye in turn shows whether the haze is on one side only.
Cataracts usually develop over months and are often found at a routine exam. Cataracts are treated by replacing the lens.
What the Eye Doctor Will Check
A detailed scan called OCT images the retina and can show tears, detachments, and fluid under the retina.36Stoney Creek Eye Care. What Is OCT Imaging? A visual field test maps any blind spot and its size and shape.37American Academy of Ophthalmology. Visual Field Test and Blind Spots (Scotomas) The shape of a blind spot can show whether eye disease or a brain problem is responsible.38American Academy of Ophthalmology. Visual Field Test and Blind Spots (Scotomas)
Bring notes on when the spot started, which eye it is in, and whether it moves. Mention any flashes, headaches, or wavy lines, and bring photos of any visible mark. Bring sunglasses and a driver, because dilating drops blur vision for hours.
The drops widen the pupil over about 20 to 30 minutes. The doctor then shines a bright light to view the whole retina. It is painless, though light sensitivity lasts a few hours.
For the visual field test, you rest your chin on a support, look at a central light, and press a button each time you see a faint light flash elsewhere. Each eye is tested separately. It takes several minutes per eye and can feel tiring, and missing some lights is normal; it does not mean you failed. The pattern of missed lights is drawn as a map, and its shape and position help the doctor work out where along the visual pathway the problem lies.