By Shafiq Rehman, Consultant Ophthalmic Surgeon at Optegra Eye Health Care.

Our bodies are very clever at giving us indications that something is wrong.  From an increased heartbeat when stressed, to muscle twinges when putting too much strain on our backs.

And our eyes are no different.  

There are a number of signs that something may be amiss – but we need to recognise them!  And as several sight-threatening eye conditions may have no symptoms as such in the earliest stages, these ‘red flags’ are definitely not to be ignored.

Within eye health, the earlier a serious eye condition is detected, the better the chances of successful treatment. 

Unfortunately, new research The Optegra eye hospital group found that 32 percent of adults have missed an eye test during lockdown – a crucial tool for us as we work to protect eye health.

Yet British adults are reporting many symptoms which they have experienced over the past year:

  • A quarter (25 percent) of all adults have experienced not being able to read clearly without glasses or contacts, and of these 37 per cent have struggled with this in the past year
  • 24 per cent of Brits have experienced headaches over their eyes – 57 percent of whom have experienced this in the past year
  • 21 per cent have had floaters affecting their vision, with 36 per cent doing so in the past year
  • 21 percent have had blurry vision, 46 per cent of whom had this in the past year

In fact the research shows that 44 per cent of UK adults are concerned about their eye health post lockdown.

It may reassure people to know about the ‘red flags’ when it comes to eyesight, so you can get yourself checked out as soon as possible if needed.

If you experience any of the following symptoms, let your optometrist know straight away as it could be a sign of....

Blurry vision, pain in eye with nausea, sudden loss of vision, appearance of rainbow circles around bright lights

Could be the first signs of glaucoma.  Glaucoma appears in different forms and is a group of eye conditions in which the optic nerve becomes damaged, usually due to a rise in intraocular pressure (IOP).

The most common form of glaucoma is 'open angle glaucoma' and is known as the 'silent thief of sight' as there are no symptoms or early signs - and so it is crucial to have an eye test every one-two years if you have a family history of glaucoma.  From age 40 you are eligible to have free NHS annual eye tests. 

Symptoms to look out for in 'angle-closure glaucoma' include eye and head pain, the appearance of rainbow colour circles in bright lights, and blurry vision. The pain can cause nausea and vomiting and can even lead to sudden sight loss.

These symptoms can develop quickly and are immediately noticeable. 

Clouding vision or glare from lights in the dark

Could be signs of cataract.  This affects one in three adults aged over 65 years, and is part of the natural ageing process.  

A cataract is a painless gradual clouding of the eye’s natural lens, which lies behind the pupil and the iris.

It can feel as though you are looking through cracked or frosted glass when you have a cataract, as your vision becomes blurred. This can seem like a mere inconvenience at first. However, if you leave it untreated, it can result in blindness. A cataract can also be extremely detrimental to your ability to do everyday tasks such as reading and driving.

Blurring of central vision or losing ability to judge distance when walking

Could be a sign of Age-related Macular Degeneration.  As we get older, the macula (the central part of the retina responsible for detailed vision) can begin to break down, causing blurred vision.

The earliest sign of macular degeneration is often the appearance of small yellow deposits called drusen, which form under the retina. These are accumulated waste products which, as they get larger, stop the flow of nutrients to the retina and cause the layer of supporting cells beneath it to become very thin. 

When cells in this layer die, the overlying macula degenerates and loses its visual function.

Age-related macular degeneration (AMD) is a leading cause of visual impairment in the UK.

Cannot read small print eg phone messages or newspapers

Could be a sign of Presbyopia - the lens of the eye naturally loses its elasticity and flexibility as we age.  This affects focusing power and so many people need to start wearing reading glasses at this age.  

Presbyopia affects everyone from around our mid forties onwards and becomes more pronounced as we age.  Many people start by just holding things further away but eventually our arms aren’t long enough to keep things in focus without reading glasses.

Thankfully it is possible to undergo a highly specialised form of laser vision correction – called Presbyond for early cases and Refractive Lens Exchange with multifocal lens implants for more advanced presbyopia.

Blurred vision

Could be a sign of diabetes. Diabetes is a chronic metabolic disorder characterised by insufficient insulin production or insensitivity to insulin, which leads to too much sugar (glucose) in the blood.  Regulating blood glucose levels is extremely important. Untreated diabetes can result in damage to blood vessels, nerves and organs such as the kidney and the eye.

The retina is situated at the back of the eye and responsible for detecting light and transmitting this signal to the brain, resulting in a visual image.

These vessels can be damaged by the high blood sugar levels often seen in non-treated diabetes or diabetes that is not completely controlled. This is known as diabetic retinopathy, which can take several forms.

Patterns and shapes disturbing vision

Could be floaters or diabetes.  Small patterns floating across your vision are called floaters.  They are within the vitreous solution - the fluid which fills the eyeball - and in most cases are mild enough that the person gets used to them and learns to ignore them. 

A condition called posterior vitreous detachment is also possible, here the vitreous gel pulls away from the retina and optic nerve leading to sometimes quite dramatic floaters arising, often accompanied with flashing lights.

If this occurs then it is important to have an eye specialist or optometrist examine your eyes to ensure that the retina itself has not suffered some damage during this process.

For people who are troubled by floaters that do not recede a procedure termed Vitrectomy can be considered where the majority of the vitreous gel can be removed and replaced with clear liquid. 

Floaters can also be a sign of diabetes - and so your GP or optometrist may also arrange for you to have retinopathy to check the eye health at the back of your eye - as diabetes can damage the blood vessels within the eye.

Flashing lights or a dark 'curtain' across your vision

Could be a sign of retinal detachment.  Sudden onset of flashing lights in your vision can be an indication of retinal detachment which is a serious, sight-threatening condition which needs urgent attention. The thin, light sensitive layer at the back of the eye becomes separated from the wall of the eye. 


The most common cause of retinal detachment is small tears in the retina which then allow fluid to get beneath the retina and separate it from the nutrient layer underneath.

Retinal tears or holes are more likely in short-sighted (myopic) eyes, after a posterior vitreous detachment (a normal ageing change) or after cataract surgery, and can occur in diabetic eyes. Again it is important to arrange a visit with your optometrist as a starting point. 

Irritable sore eyes and itchy eyelids

Could be blepharitis - eyelid inflammation. It is one of the most common eye conditions but there are treatments such as eye drops, cleansing pads and eyelid scrubs.  It is best to speak to your optician to check you to not have an allergy or infection that needs treatment. 

At this time of year with pollen levels extremely high across the UK allergic conjunctivitis is a common affliction, this can cause quite intense itching, watering and red eye.

One of the most effective ways to control allergic conjunctivitis is to refrain from rubbing your eyes – although this can be quite hard to do! Eye rubbing causes release of chemical factors onto the eye surface which exacerbates the itching.

Other remedies are antihistamine eye drops and or tablets many of which are available over the counter so speak with your local pharmacist if affected by this seasonal affliction.

Persistent gritty dry eyes

Could be dry eye disease.  This can be managed with over-the-counter lubricant eye drops available from pharmacies and optometrists. When more severe and not responding to simple lubricant eye drops, then a referral to an ophthalmologist may be required for further management. 

Difference in pupil size

Could be Holmes-Adie pupil.  The most common reason for new onset pupil size difference – termed anisocoria - is a condition called Holmes-Adie pupil, where one  pupil becomes enlarged relative to the other.

This condition is benign however if you notice this kind of change it is very important to visit your optometrist for an examination to rule out more serious conditions.

Sudden onset of double vision

Could be muscle-weakening.  Termed Diplopia, this should always merit specialist attention although very often the underlying cause may be relatively benign, sudden onset diplopia could be indicative of one or more eye muscles becoming weakened due to the loss, or interruption of, the microscopic blood supply to the nerves that innervate them.

This is called micro-vasculopathy and can sometimes be an indication of a more generalised medical problem such as Diabetes, high blood pressure and other anomalies.

A pre-existing childhood tendency to squint can also sometimes recur in our later years, either way it's important to touch base with your optometrist or GP in the first instance before specialist referral is sought.

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