ConditionEyes & vision
Asteroid Hyalosis
Asteroid hyalosis is a harmless eye condition in which hundreds of tiny white or cream particles made of calcium and fats float in the vitreous, the clear gel inside the eye. Under an examination light they sparkle like stars, which gives the condition its name. It usually affects one eye in people over 60 and rarely causes symptoms, because the particles move with the gel and stay out of the line of sight. Most people need no treatment, only routine eye checks.
Also called: Asteroid bodies, benign asteroid hyalosis, Benson disease
At a glance
- What it is
- Tiny calcium and fat particles suspended in the vitreous gel of the eye.
- Who gets it
- Mostly people over 60, men slightly more than women. Usually one eye only.
- Symptoms
- Usually none. Occasionally mild floaters or glare.
- Is it serious?
- No. It does not damage vision or turn into another disease.
- Treatment
- None needed in most cases. Vitrectomy only if vision is affected or the retina cannot be seen for other treatment.
When to get help
Call 911 or go to the ER
- A sudden shower of new floaters, flashing lights, or a shadow or curtain across your vision (possible retinal tear or detachment)
- Sudden loss of vision in one eye
See a doctor within a day or two
- A sudden increase in floaters with blurred vision, especially if you have diabetes (possible bleeding in the eye)
Book a routine appointment
- Asteroid hyalosis found on a routine eye exam, especially if you have diabetes: keep regular retina checks
- Gradually blurred vision or glare that bothers you
Usually safe to manage at home
- Known asteroid hyalosis with stable vision and no new symptoms
What asteroid hyalosis is
The vitreous is a clear gel that fills the back of the eye. In asteroid hyalosis, small round particles called asteroid bodies form within the gel. They are made of calcium and phosphate bound to fats (phospholipids), and they are attached to the gel's collagen framework. When the eye moves, they swirl and then settle back into place, like snow in a snow globe.
It is not the same as ordinary floaters, which are clumps of collagen fibers that cast shadows on the retina. Asteroid bodies are highly reflective under the bright light of an eye examination, but they often cast little shadow, so most people do not notice them.
Causes and risk factors
The exact cause is unknown. It is thought to be a degenerative change in the vitreous. It is more common:
- with age, becoming more frequent after 60
- in men
- in people with diabetes, high blood pressure and high cholesterol in some studies, though the link is not consistent
It is not inherited and is not caused by diet, eye strain or anything you did.
Asteroid hyalosis affects roughly 1% of adults, and about three-quarters of cases involve only one eye.
Symptoms
Most people have no symptoms, and the condition is discovered during a routine eye examination. A few notice:
- faint floaters or specks
- mild glare or haze in bright light
- very rarely, reduced sharpness of vision when the bodies are very dense
Because the particles are fixed within the gel, they move only slightly and do not usually drift across the center of vision.
Asteroid hyalosis vs other causes of floaters
| Condition | What it is | Key features |
|---|---|---|
| Asteroid hyalosis | Calcium-fat particles in the gel | Often no symptoms, sparkling bodies on exam, usually one eye |
| Common floaters | Clumped collagen fibers | Strands, cobwebs, specks that drift, very common |
| Posterior vitreous detachment | Gel separating from the retina | Sudden new floaters, sometimes flashes, needs exam to exclude a tear |
| Vitreous hemorrhage | Bleeding into the gel | Sudden dark floaters or a red haze, often in diabetes |
| Synchysis scintillans | Cholesterol crystals in a liquefied gel | Rare, usually after previous eye trauma or bleeding, crystals sink to the bottom |
Diagnosis
An optometrist or ophthalmologist diagnoses it with a slit lamp microscope and an examination of the back of the eye after dilating drops. The bodies look like glittering white dots throughout the gel.
Dense asteroid hyalosis can make it hard to see the retina clearly. This matters for people with diabetes, who need regular retina checks for diabetic retinopathy. In those cases, doctors use:
- optical coherence tomography (OCT): a scan that images the retina through the particles
- fluorescein angiography: a dye test of the retinal blood vessels
- ultrasound of the eye
Treatment
No treatment is needed for most people. Asteroid hyalosis does not cause blindness and does not need to be removed.
Treatment is considered when:
- the particles noticeably reduce vision or cause troublesome glare
- they block the view of the retina when a retinal disease needs monitoring or laser treatment
The treatment is a vitrectomy, an operation to remove the vitreous gel and replace it with a clear fluid. It carries risks, including retinal detachment, infection and cataract, so it is reserved for clear benefit.
Cataract surgery
People with asteroid hyalosis can have normal cataract surgery. The particles can interfere with measurements for the replacement lens, so the surgeon may use specific measurement techniques. Some lens types, particularly silicone lenses, can attract calcium deposits, so surgeons may choose a different lens material.
Outlook
Asteroid hyalosis is benign and usually stable for life. It does not usually get worse in a way that affects vision. Continue routine eye examinations, and seek prompt care for any sudden new floaters, flashes or vision loss, since these signal a different problem.
Frequently asked questions
Is asteroid hyalosis serious?
No. Asteroid hyalosis is a benign condition that rarely affects vision. It does not lead to blindness or other eye diseases. Routine eye checks are still important, especially if you have diabetes, because dense particles can hide retinal problems.
What causes asteroid hyalosis?
The cause is not fully known. It is a degenerative change in the eye's vitreous gel where calcium and fat particles form. It becomes more common with age and may be associated with diabetes, high blood pressure and high cholesterol.
Does asteroid hyalosis cause floaters?
Usually not noticeably. The particles are suspended in the gel and reflect light rather than casting strong shadows, so most people have no symptoms. Some notice faint specks or glare. New, sudden floaters should always be checked.
Can asteroid hyalosis be treated?
Treatment is rarely needed. If the particles reduce vision or block the doctor's view of the retina, a vitrectomy can remove the vitreous gel and the particles. Because surgery carries risks, it is only done when the benefit is clear.
Does asteroid hyalosis affect both eyes?
It usually affects only one eye. In about a quarter of people it is found in both eyes, often more marked in one.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Ophthalmology (AAO) EyeWiki: Asteroid hyalosis
- American Academy of Ophthalmology: Floaters and flashes
- National Eye Institute: Floaters
- Merck Manual: Vitreous disorders