Floaters and Flashes -- When to Worry and When to Get Checked

What floaters are

Floaters are shadows. Inside your eye is a clear gel called the vitreous, which fills the space between the lens and the retina. Over time – and especially after age 40 – the vitreous becomes more liquid and develops clumps of collagen fibres. These clumps cast tiny shadows onto the retina, which you see as spots, threads, cobwebs, or shapes drifting across your field of vision.

They are most noticeable against bright or uniform backgrounds – a white wall, a blue sky, a lit screen – and they move when you move your eyes. If you try to look directly at one, it drifts away.

Most floaters are harmless.

When floaters are not harmless

A sudden change in floaters is what matters. The pattern that needs urgent assessment is:

• A sudden shower of new floaters – many more than usual, appearing over minutes to hours
• Flashes of light – brief streaks or arcs, usually in your peripheral vision, often more noticeable in dim lighting
• A shadow or curtain – a dark area spreading across part of your visual field from one side

This pattern can indicate a posterior vitreous detachment (PVD) that has caused a retinal tear. A PVD happens when the vitreous gel separates from the retinal surface – this is a normal event that happens to most people, usually after age 50 and earlier in people with high myopia. In most cases, the vitreous separates cleanly and the result is just some new floaters. But in a small percentage of cases, the vitreous tugs on the retina as it separates and tears it.

A retinal tear caught early can usually be sealed with laser treatment. A tear that progresses to a retinal detachment – where fluid gets behind the retina and lifts it away from the wall of the eye – typically requires surgery and carries a risk of permanent vision loss.

The window matters. The time between a retinal tear and a detachment can be hours to days. This is why we take new-onset floaters with flashes seriously and try to see patients the same day.

What happens when you come in

If you call us about new floaters or flashes, we will perform a dilated retinal exam. This involves:

1. Dilating drops – we use drops to widen your pupils so we can see the full peripheral retina, not just the central area
2. Retinal examination – using a specialized lens and light source, we examine the entire retinal surface, looking for tears, holes, detachment, haemorrhage, or areas of vitreous traction
3. Retinal imaging – a high-resolution photograph of the retina that documents what we see and provides a baseline for comparison
4. OCT scan – a cross-sectional scan of the retinal layers that can reveal fluid, traction, or structural changes not visible on surface examination

After the exam, we will show you the images and explain what we found. In most cases, the retina is intact and the floaters are from a benign vitreous change. In that case, you go home with a clear answer and a documented baseline.

If we find a tear or suspicious area, we refer urgently to a retinal specialist – usually the same day.

Note: your vision will be blurry for a few hours after dilation. Bring sunglasses and arrange not to drive if possible.

Why imaging and OCT matter for floaters

A single exam can tell you whether your retina is intact right now. But retinal conditions develop over time, and having baseline images to compare against is what makes future exams more powerful.

Retinal photos show the surface of the retina – the blood vessels, optic nerve, macula, and peripheral retina. OCT shows the layers beneath the surface, including fluid or structural changes that are not visible on a photo.

When we have your images from a previous visit, we can compare year over year and detect:

• New areas of vitreous traction that may not yet be causing symptoms
• Subtle changes in retinal thickness that could indicate early disease
• Progression or stability of findings that are being monitored

This is especially valuable for patients at higher risk: those with high myopia, diabetes, a family history of retinal detachment, or a previous PVD in one eye (the other eye often follows within a few years).

At Spadina Optometry, retinal imaging and OCT are part of our comprehensive exam. We keep your images on file and compare them at every visit. For patients with floaters, this year-over-year tracking is one of the most effective tools we have for catching problems early – before they cause symptoms.

Who is at higher risk

Some people are more likely to develop floaters earlier or to have floaters that signal a problem:

• Age over 50 – PVD becomes increasingly common
• High myopia (above -4.00 to -5.00) – the longer eye shape causes vitreous changes earlier and increases retinal tear risk
• Previous eye surgery – cataract surgery, LASIK, or vitrectomy can accelerate vitreous changes
• Previous PVD in one eye – the other eye often follows within a few years
• Diabetes – floaters can result from vitreous haemorrhage related to diabetic retinopathy
• Eye injury or inflammation – trauma or uveitis can cause floaters at any age

If you fall into any of these groups, mention it at your exam so we can adjust monitoring accordingly.

Can floaters be treated?

Most floaters do not need treatment. The brain adapts over weeks to months, and most people find that floaters that were distracting at first become much less noticeable.

For floaters that are persistent and significantly affect daily vision or quality of life, treatment options exist but are typically reserved for severe cases:

• Laser vitreolysis (YAG laser) – a laser is used to break up large floaters. Not suitable for all types or locations of floaters.
• Vitrectomy – surgical removal of the vitreous gel. Effective but carries surgical risks and is reserved for cases where floaters cause substantial functional impairment.

These are specialist procedures and not first-line treatments. For most patients, the right approach is reassurance, a confirmed baseline, and regular monitoring.

When to call us

Call the same day if you have:

• A sudden increase in the number of floaters
• Flashes of light, especially in your peripheral vision
• A shadow or curtain across part of your vision
• Any sudden change in vision

Book a routine exam if you have:

• Floaters that have been stable for a while but have never been assessed
• A history of high myopia and no recent dilated exam
• Anxiety about floaters and want a clear answer and a documented baseline

At Spadina Optometry in downtown Toronto, we see urgent floater and flash patients and can usually fit you in the same day. Call us at 416-703-2797.

Related

• Urgent eye problems – optometrist vs ER – when to call, when to go to emergency
• Retinal imaging, OCT, and eye health – what imaging shows and why it matters over time
• How often should you get an eye exam? – monitoring schedules based on risk
• Eye exams for diabetes and high blood pressure – diabetic retinopathy and floaters