Eye emergencies

What are eye emergencies?

Emergencies to do with the eyes or vision typically cause problems to develop quite quickly, over a matter of minutes or hours. These problems should be dealt with urgently, ideally receiving professional advice within hours. First, we will describe the conditions that should cause concern. We will then outline the action that needs to be taken. Most eye emergencies involve either (a) a painful red eye or (b) a sudden change in vision.

Painful red eye

If you have developed a painful red eye then this could be a serious eye infection, such as an ulcer, and needs urgent attention (see below). This is especially important if you are a contact lens wearer, in which case you should immediately remove your contact lenses. If the eye is still painful and red then follow the advice below DSC00117without delay.

If your eye is not painful, but an area of the white of the eye has gone a deep red, like the picture on the left, then this may just be a harmless condition called a sub-conjunctival haemorrhage. If there is no pain, discomfort, or change in vision and this only happens once then it does not require investigation, and the red area should gradually fade over a week or two. If there is any discomfort, pain, discharge, or change in vision then follow the advice below for urgent attention.

Another quite common problem is an eye which is uncomfortable, with a feeling like there is some grit in the eye. This may be a foreign body in the eye, or an in-growing eyelash. You could try to make an early appointment at the practice within the next few days. But if there is any pain, redness, or visual disturbance then follow the advice below for urgent care. If you are a contact lens wearer then please follow the advice below, and when you contact us, tell the person you speak to that you are a contact lens wearer.

Visual disturbance

Vision often changes gradually over time (e.g., over months) and this is a sign that you need a routine eye examination with your optometrist to see if your spectacles or contact lenses need updating. In contrast, a sudden change in vision is a serious sign and always requires urgent investigation. To identify a visual disturbance you may need to cover each eye in turn to test the vision of one eye at a time. It is useful to do this whilst looking at a picture of a grid, such as an Amsler grid (pictured below). Click here for instructions on how to use an Amsler grid.

A sudden change in vision can take many forms and each of the following problems, which are described in more detail below, may be a serious warning sign:

bstrbu1 floaters

bstrbu1 flashes

bstrbu1 visual loss or black-outs

bstrbu1 loss of peripheral vision

bstrbu1 blur

bstrbu1 double vision

bstrbu1 distorted vision

Floaters are tiny particles within the eye which appear as floating specs when we view a bright background, such as a white wall or the sky. If you try to look at a floater, it will appear to move as your eye moves. Most people experience some floaters, but the sudden appearance of a new floater or shower of floaters always requires urgent investigation. The appointment to investigate these will require drops and you should avoid driving for a few hours after the appointment (see below).

Flashes of light, sometimes appearing like a small fireworks display in one eye, can be a serious sign and again requires urgent investigation and an appointment when eye drops are used. The flashes are usually only noticed in the dark. A different type of flashes occurs in visual migraine. These usually occur in both eyes and in younger people are often followed by a headache. In older people, there may be no headache but the person will often have been a headache sufferer when they were younger. These flashing lights typically occur in daytime and last between 5 and 30 minutes. If they are in both eyes then this type of visual migraine does not require urgent attention, providing there is no other disturbance to vision and the situation does not worsen.

Sudden loss of vision can occur in an eye or in part of the field of vision (e.g., on the right hand side of where you are looking). This requires an urgent hospital appointment (see below). Some people notice an effect where their visual field seems to be shrinking, like a curtain moving in from one side. If this occurs in both eyes for a few minutes as part of a migraine attack, usually with flashing zig-zag patterns, then it will pass within half an hour or so. This would not usually be a cause for concern if you are known to have a history of migraine. But if the visual field loss is not associated with migraine, is a total blackout of vision, or only occurs in one eye then it requires urgent attention. The investigation of this sort of problem is likely to required a brain scan, which cannot be arranged by a community optometrist. This is why people with this sort of problem should seek an urgent hospital appointment and not visit an optometrist first, since this would cause unnecessary delay.

Sudden blurring of the vision in one eye can be a serious sign. Of less concern is an occasional blurred vision for a few moments caused by mucus in the tear film. If blinking clears the vision then the problem is just mucus. As long as this is not associated with redness or pain then it does not require urgent attention. But if one eye becomes blurred quite suddenly and it does not clear with blinks then it requires urgent attention.

If you have never had double vision and this suddenly develops then you should seek urgent professional attention. This is likely to be a problem in the brain affecting the control of eye muscles, and so is likely to need a brain scan. Therefore, people who have suddenly developed double vision should go to a hospital A&E clinic, rather than an optometrist.

Another problem which can be a serious sign is distorted vision in one eye. Often, people notice this when looking at straight lines (e.g., window panes or computer spreadsheets, which may appear to have a kink). It can be detected with an Amsler grid (pictured above). If the problem has come on quite quickly then you need to see an eyecare professional very soon, within a few days. This appointment will require drops, so you should avoid driving for a few hours after the appointment.

What do you mean by “urgent attention”?

Frequently in this document we have recommended that an eye problem needs urgent attention. As a general rule, the speed of onset of your symptoms is a guide to the speed with which you should seek professional care. For example, if you are seeing floaters in one eye that have not suddenly changed but you have gradually become more aware of them over the last few months then this would not require an urgent appointment. Instead, telephone our reception for a routine appointment but explain about the floaters so that reception can arrange an appointment when drops are used. On the other hand, if you have today become suddenly aware of a new floater, this should ideally be investigated today. Most of the problems described in this document are of sudden onset, so they require urgent attention. Usually, this should be within 24 hours of you noticing the symptom, ideally within a few hours. If your symptom is worsening (e.g., visual loss in one eye or pain that is worsening over a few hours) then you should try and obtain professional advice within an hour or two.

Can I be seen at your practice for this “urgent attention”?

Optometrists don't routinely provide an emergency service, but whenever possible we try to see patients with urgent problems. There are two difficulties with this: first, some problems (e.g., floaters or flashes) require quite a detailed investigation, involving drops. Also, quite often these emergency cases end up needing referral to the hospital, so if we ask someone to come back for an appointment with us at the end of the day's clinic then this could cause an extra delay.


Patients sometimes ask if we “can just have a quick look”. However, for problems like flashes, floaters, or visual loss a quick check would not allow us to determine whether a potentially sight-threatening problem is present.


We appreciate that often our patients would much rather come to practice so that we can tell them whether they need to go to hospital. If you telephone our practice with one of the problems outlined above, we will try to offer you an appointment that day if one of our optometrists is available. If we are fully booked, we will recommend you to go to a hospital, as summarised below. Also, if your condition is worsening then it is better to go directly to the hospital.


Will I have to pay a fee?

The standard contract that community optometrists in England have with the NHS is very limited. It only covers one item of service, the standard NHS “sight test”, which was defined in legislation 50 years ago. Optometrists’ NHS contract makes no mention of emergency appointments and a full investigation of the conditions outlined in this document usually requires a private appointment. Some areas of the country have “enhanced service optometrist (ESO)” schemes where the NHS pays optometrists a special fee for these detailed investigations. We participate in two ESO schemes in Essex and, depending on the location of your GP’s surgery, you may be eligible for an appointment funded in this way. If you telephone our reception for an emergency appointment, they will advise whether your problem is appropriate for an ESO appointment. If not, our usual private eye examination fees will be charged for these appointments, as detailed on the Eyecare page of this website.

If you have any of the problems outlined in this document then it is most important that you receive appropriate professional care. The NHS does fully fund the investigation of these problems in hospitals, as outlined in the next section.

Where else can I go for “urgent attention”?

If we are closed or, for any reason, you cannot reach the practice or we cannot see you, NHS 111 is always available and is designed to give the right advice and treatment when it is urgently needed.

Most local hospitals have an eye (ophthalmology) clinic which is staffed by eye surgeons, and this is the case for Queens, Broomfield, Orsett, Southend, and Whipps Cross Hospitals. If you telephone the hospital and ask to be put through to the eye clinic then usually an ophthalmic nurse will be able to provide expert advice. The clinic hours vary, but are usually typical office hours on weekdays only.

What can you do if you have an eye emergency when we and the local hospital eye clinics are closed? The eye is a very specialist organ and the Accident and Emergency Department of a local hospital is not usually the best place to be examined if you have an eye problem. The staff in these departments are of course exceptionally skilled and dedicated. But you could arrive, have a long wait, and then be seen by someone who is not an eye specialist and who may have to refer you on to the eye clinic, possibly the next day. Such a delay, apart from being inconvenient for you, could have serious implications for your eye problem.

We are very lucky in Brentwood in that one of the best eye hospitals in the world, Moorfields Eye Hospital, is only about an hour away. This eye hospital has a 24 hour eye A&E clinic that aims “to provide a first class service to people who have eye emergencies such as pain or vision loss”. More information can be found at A&E - Moorfields Eye Hospital. The Moorfields website stresses, their service is for existing Moorfields patients and those who live locally to Moorfields Eye Hospital. Their website provides two numbers, 020 7566 2345 and, for A&E queries out of hours, 020 7253 3411.


Updated May 2021


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