Sight conditions

The eye examination not only measures your prescription (and the powers of corrective lenses for you, if needed). It’s also where sight conditions can be detected early, increasing the likelihood of successful treatment.

Common sight conditions are listed to the right, or below if you’re viewing this page in a narrower window. Click the [+] next to each title to read more.

We strongly recommend our Premium examination  which includes OCT scans, so that all aspects of your eye health can be examined in detail, screening for many conditions such as cataracts, glaucoma, high blood pressure, diabetes and macular degeneration (dry or wet). We will take images of each eye and take the time to explain them to you, showing you the different areas on the pictures such as the optic nerve, the blood vessel system and the critical, central region of retina, known as the macula. The OCT scans the deeper layers of the eye and can pick up even early signs of eye conditions such as Macular Degeneration and Glaucoma. The computer software can then compare these images when you next have a scan, picking up any changes that may be important.

Retinal photography gives us instantaneous ‘snapshots’ of your eyes, but also allows us to build up a record over the years and monitor any changes
OCT scan
OCT scanning gives cross-sectional 3D information as well as the retinal snapshots
It is normal for the focussing lenses inside our eyes to change with age, gradually becoming less clear. This has the effect that less light passes through, and light can also become scattered within the eye. The eye then becomes more sensitive to bright light and the vision becomes foggier. A cataract develops causing the lens to become cloudy or more opaque and, as the opacity increases, the vision deteriorates.

The most common cause of a cataract is the normal ageing process described above and most people start developing cataracts in their late 60’s. It can also develop due to trauma, radiation or diabetes. The progression of cataracts is highly variable and if your vision is reduced to a point that your lifestyle is affected, cataract surgery is usually performed.

Cataracts can be detected and tracked through thorough eye examinations and thousands of people undergo successful treatment each year and continue to enjoy great vision.


Glaucoma is a disease of the optic nerve, often associated with elevated eye pressure, which can cause blind spots in your field of vision and eventually tunnel vision, if left untreated.

As there is usually no pain and your vision deteriorates gradually, you will probably be unaware you have glaucoma until it is well developed. Glaucoma mainly affects people over the age of 40; however you could also be at risk if you have a close relative who has or had glaucoma, if you are of Afro-Caribbean origin, or suffer from diabetes.

Fortunately glaucoma can be detected even in its initial stages by an eye examination. The optometrist checks the health of the nerve inside the eye, the pressure of the fluid within the eye, and also checks the visual field for any early defects. Glaucoma can usually be treated successfully by eye drops. If it is diagnosed early enough it should not normally hinder you from enjoying good eyesight.

Macular Degeneration

The macula is the centre of the retina at the back of the eye. It is the area of the retina that you use to see straight ahead, to see colours and to perform detailed visual work, such as reading, driving or watching television. Degeneration of the macula, which is generally associated with increasing age, but can be genetic, therefore only affects your central vision, leaving peripheral vision intact.

90% of people with Age Related Macular Degeneration (AMD) have the dry form in which there are pigment changes and waste deposits accumulating between the layers of the retina and, causing central vision to become less clear. Currently there is no treatment for this, but some studies indicate that nutritional anti-oxidant supplements, such as Macushield, will be of benefit. Also individuals whose diets are rich in leafy green vegetables and don’t smoke could reduce the risk of developing Age Related Macular Degeneration. Regular use of sunspecs on bright days, to cut out ultra-violet rays, is also beneficial.

The wet form of AMD is where blood vessels grow into the macula and then leak blood or fluid, which can rapidly and significantly reduce your central vision. There are some treatments available for wet AMD, either with injections or surgery: an ophthalmologist can assess your suitability.

Retinal Detachment
The retina is the inner layer of the eye and it contains the photoreceptors (light sensitive cells which detect colour and black and white).
A retinal detachment is when the retina pulls away from the back of the eye. It can start with a small tear, but if not treated quickly can lead to long-term damage to your vision.

Some people, including those who are short-sighted and those with a family history of retinal detachment, are more at risk of retinal detachment. The most common symptoms are flashes of light or dark spots floating in vision (‘Flashes and Floaters’ – see below) but sometimes there can just be a shadow on one side of your vision.

Flashes and Floaters
Floaters look like small, dark spots or strands that appear to float in front of your eyes. People often feel as if there is a hair or insect in front of the eye. They are very common and usually harmless. Some people occasionally see flashes of light which can be due to movement of the gel in the eye. They can appear like small sparkles in the corner of your vision or even lightning flashes across your vision. These are different to the shimmering or zig-zag lines or arrows that may be part of a migraine (see below).

Some people are born with floaters but they are more common as you older when the gel shrinks in the eye. The gel can come away from the retina completely- this is a normal occurrence called Posterior Vitreous Detachment. The symptoms of Retinal Detachment and Posterior Vitreous Detachment are almost identical. If you get any of the following symptoms you should contact your optometrist or attend A&E on the same day:

  • A sudden increase in floaters, particularly if you also notices flashing lights
  • A new, large floater
  • A change in floaters or flashing light(s) after a direct blow to the head or eye
  • A shadow spreading across the vision of one or both eyes.
Ocular Migraine
Before a migraine headache it is not uncommon to experience shimmering lights or zig-zags in your vision. These often start in the corner of your vision and spread to more than half — sometimes in one eye only. It can last 10–30 minutes. This can then lead to a severe headache, light sensitivity and nausea, but for a lot of people it does not progress to this.

New migraines in someone who has not suffered with them before, or more frequent migraines, warrant further investigation involving your optometrist and GP. It can be helpful to keep a Food and Activity diary to help identify the cause.

Common causes are food and drink (chocolate, cheese, wine or coffee), stress or photo-sensitivity.

Uncomfortable eyes?

Read more about Dry Eye and Blepharitis >>