When to Seek Urgent Eye Care
A sudden change in your vision is not something to ignore. Sudden loss of vision, new flashes or floaters, a shadow moving across your sight, or a painful red eye can be warning signs of a serious eye condition.
If you suddenly lose vision in one or both eyes, seek immediate medical assessment, even if your vision returns to normal. If you also experience facial drooping, weakness, difficulty speaking or other signs of a stroke, call 111.
At Ashburton Eyecare, our Therapeutic Optometrists want people across Ashburton and Mid Canterbury to recognise the warning signs, understand where to seek help and know why early assessment matters.
The 4 Fs: Four eye-health warning signs
A useful way to remember some of the most important warning signs is the 4 Fs: flashes, floaters, falling curtain and failing vision.
1. Flashes: New sparks or streaks of light
Have you suddenly started seeing brief flashes, streaks or sparks of light, particularly towards the edge of your vision?
Flashes can occur when the gel inside the eye moves and pulls on the retina. Sometimes this is part of a common age-related change. However, the traction can also cause a retinal tear, which may progress to a retinal detachment.
New or sudden flashes should be assessed promptly, particularly when they affect one eye or occur alongside new floaters or reduced vision.
2. Floaters: New spots, specks or cobwebs
Floaters can look like small dots, threads, transparent strands or cobwebs drifting across your vision. They are often most noticeable when looking at a bright sky or a plain, light-coloured surface.
Many people experience floaters as they get older, and existing floaters are often harmless.
The important distinction is a sudden appearance of new floaters or a noticeable increase in their number. This can indicate changes within the eye that need assessment. New floaters accompanied by flashes, a shadow or reduced vision warrant urgent attention.
An optometrist can examine the retina to look for a tear, detachment or another cause.
3. Falling curtain: A shadow across your vision
A dark or grey shadow that seems to spread across your vision can be a warning sign of a retinal detachment.
The shadow might begin at the edge of your vision and gradually move towards the centre. Retinal detachment is often painless, so the absence of pain does not make it less concerning.
A new curtain-like shadow is an eye emergency. Seek urgent assessment immediately. Delaying treatment can lead to permanent sight loss.
4. Failing vision: Sudden blur, dimming or loss of sight
Sudden or rapidly worsening vision should never be dismissed as tiredness, a change in glasses prescription or something that will simply clear on its own.
Vision loss can arise from problems within the eye, including retinal blood vessel blockages or retinal detachment. It can also be associated with neurological or vascular conditions, including a transient ischaemic attack (TIA) or stroke.
The change may affect one eye or both. It may be complete, partial or temporary.
Even if your sight returns, sudden or temporary vision loss requires immediate medical assessment. If stroke symptoms are present, call 111 rather than waiting for an eye appointment.
Other eye symptoms that need urgent attention
The 4 Fs are not the only warning signs. Other presentations can also require urgent assessment.
A painful, red eye
A red eye is not always a simple infection or irritation.
A very painful red eye, particularly with blurred or misty vision, coloured halos around lights, headache, nausea or vomiting, may indicate acute angle-closure glaucoma. This condition can cause a rapid rise in eye pressure and is a medical emergency.
Seek immediate medical attention if you experience this combination of symptoms.
Eye injury or chemical exposure
Eye injuries can cause damage that is not always obvious from the outside. Blurred vision, significant pain, light sensitivity, blood in the eye or an object embedded in the eye needs urgent medical attention. Ashburton Eyecare is registered with ACC and can quickly and promptly remove eye foreign bodies.
If a chemical splashes into your eye, immediately rinse it with clean running water for at least 15 minutes. Strong chemicals or ongoing burning and stinging require emergency medical advice; call 111 where indicated. Do not delay irrigation while arranging help.
An object that has penetrated the eye should not be removed or pressed on. Seek emergency care.
New or unusual visual disturbances
Migraine can cause shimmering lights, zigzag patterns and temporary areas of missing vision. However, not every visual disturbance is migraine.
First-time, substantially changed or unexplained symptoms — particularly sudden symptoms affecting one eye or occurring later in life — need urgent clinical assessment. Do not self-diagnose a new episode as migraine.
What should you do if you notice a red flag?
The right care pathway depends on the symptoms and their severity.
Sudden vision loss or a new curtain-like shadow: seek immediate assessment. Do not wait for a routine appointment.
Stroke symptoms: call 111 immediately.
New flashes or floaters: arrange prompt assessment. If accompanied by a shadow, reduced vision or sudden deterioration, seek urgent care immediately.
A painful red eye with blurred vision, halos or nausea: seek immediate medical attention.
A serious eye injury or chemical exposure: follow emergency guidance and seek immediate care.
If you are unsure where to go, contact an appropriate urgent eye-care or medical service for advice. Do not delay emergency care while trying to reach a particular provider.
Why a comprehensive eye examination matters
An eye examination is more than a sight test.
A vision screening can help determine whether someone may benefit from glasses, but it does not establish whether the eyes are healthy. A scan is one source of clinical information, and pupil dilation is an examination technique — neither is a diagnosis on its own.
A comprehensive eye examination brings together the patient's history, symptoms, clinical signs and appropriate investigations. Depending on the presentation, this can include examining the front and back of the eye, assessing the retina and optic nerve, measuring eye pressure, and evaluating vision and visual function.
The optometrist interprets those findings to determine what may be happening, what can be managed within their scope of practice and whether urgent referral or further investigation is required.
Some eye conditions, such as glaucoma, can cause irreversible damage before someone notices a change in their sight. That is why regular eye-health examinations matter even when your vision seems perfectly fine.
Urgent eye examinations in Ashburton
At Ashburton Eyecare, we recognise that a person with an urgent eye concern may not be able to wait for a routine appointment. We will always make time for urgent eye examinations.
Our Therapeutic Optometrists assess eye health, investigate concerning changes in vision and arrange appropriate referral when further medical or specialist care is needed.
If you are in Ashburton or elsewhere in Mid Canterbury and are concerned about a sudden change in your vision, contact us on 03 308 9779 and explain your symptoms and when they began.
If you have signs of a medical emergency, including possible stroke symptoms or a serious eye injury, seek emergency care without delay.
Ashburton Eyecare | Therapeutic Optometrists
139 Walnut Avenue, Ashburton
Phone: 03 308 9779
Website: asheye.co.nz
Frequently asked questions about urgent eye care:
Is sudden vision loss in one eye an emergency?
Yes. Sudden partial or complete loss of vision in one eye needs immediate medical assessment, even if the vision returns. Possible causes include retinal or blood vessel problems and neurological emergencies. Call 111 if stroke symptoms are present.
Are flashes and floaters always a sign of retinal detachment?
No. Floaters are common, and flashes can occur with age-related changes inside the eye. However, new or sudden flashes and floaters can signal a retinal tear or detachment. A sudden increase in floaters, particularly with flashes, a shadow or reduced vision, requires urgent assessment.
What does a curtain over your vision mean?
A curtain-like shadow can indicate a retinal tear or detachment. It is often painless but can threaten sight. Seek urgent assessment immediately rather than waiting to see whether it clears.
Can a painful red eye be serious?
Yes. A painful red eye with blurred vision, halos around lights, headache or nausea may indicate acute angle-closure glaucoma, which is a medical emergency. Other serious eye conditions can cause similar symptoms and also need urgent assessment.
Should I go to an optometrist or the emergency department?
It depends on the presentation. An optometrist can assess many eye-health concerns and identify problems requiring referral. Sudden vision loss, suspected stroke, serious trauma and other medical emergencies require immediate escalation through the appropriate emergency pathway. Contact an urgent eye-care service promptly when appropriate, but do not delay emergency treatment.
Can an eye test detect disease even if I can see clearly?
Yes. Some conditions, including early glaucoma, may not cause noticeable symptoms. A comprehensive eye examination assesses eye health as well as vision, helping identify problems before significant damage occurs.
Further reading
This article provides general information and does not replace an individual clinical assessment or emergency advice.
