Eye conditions

Short sighted people can see well close up but struggle with distance vision e.g. TV driving etc. In short sight or myopia the light is focused in front of the retina giving a blurred image. A minus powered lens is used to move the focus onto the retina.

Long sighted people have more difficulty seeing close objects e.g. reading VDU. Higher levels of long sightedness may also cause blurred distance vision. In long sightedness the light does not focus in time to reach the retina, this gives a blurred image. A positive powered lens is used to move the focus onto the retina.

Astigmatism gives blurring for distance and near vision. Here the front of the eye is distorted giving 2 points of focus. This is commonly described as a "rugby ball" shaped eye, the front surface has one steep curve and one flatter curve. This causes the light to focus in 2 points away from the retina. A lens with two components is required to correct the 2 focal points and move them on to the retina.

This is ageing sight. The eye naturally loses the ability to focus for near vision as we get older. This generally becomes a problem over the age of 45 years. The onset varies between people. Commonly people find they have to hold things further away to read and have more difficulty reading in poor lighting. Presbyopia is corrected using a positive powered lens, this may be in addition to any correction for short sight, long sight or astigmatism.

Amblyopia or Lazy eye is where the vision in one or both eyes is reduced even with spectacles. The eye shows no sign of disease or other abnormality. Amblyopia occurs when one eye does not recieve a clear image compared to the other in childhood.

There are 4 main causes of Amblyopia

• Strabismic - The commonest form, one eye turns in or out. The brain ignores this eye to avoid double vision. Over a short period the turned eye becomes lazy or amblyopic.
• Anisometropic - Here the eyes have unequal refractive errors, long or short sight. The brain ignores the eye with the most blurred image causing it to become lazy.
• Ametropic - Vision in both eyes is reduced due to large refractive errors equally affecting both eyes being uncorrected by spectacles or contact lenses. Neither eye receives a clear image and so are not able to develop properly.
• Deprivation - This is the rarest form. It is caused by something obscuring the vision e.g. a droopy eye lid (ptosis) or a cataract being present at birth.

Unless there is a turn in the eye or an obvious obstruction of the vision amblyopia often goes undetected until you have your eyes examined. Amblyopia is only treatable in childhood and earlier detection and treatment gives better outcomes.

Treatment varies depending on the cause, it may involve spectacles, occlusion of the good eye to encourage the lazy eye to work. Surgery may be required to straighten the eye in squint or remove the obstruction to vision in cataract.

• Cataract is a clouding of the lens inside in the eye.
• Cataracts are most commonly age related, most people over 60 will have some clouding of the lens which may or may not affect vision.
• Cataracts may occur in younger people with conditions such as diabetes or other eye conditions. Some medications can also cause the early onset of cataracts.
• Very occasionally babies are born with cataracts, these are called congenital cataracts.
• A developing cataract may cause, blurred vision, glare in sunlight or when driving at night or fading of colour vision. Should you have any of these symptoms or other concerns about eye health you should have an eye examination.
• Cataracts are removed by a surgical procedure where the cloudy lens is removed and a clear lens put in its place. This is generally performed under local anaesthetic and you can usually go home the same day.

• Glaucoma is a condition where increased pressure inside the eye causes damage to the optic nerve which leads to loss of peripheral vision.
• Glaucoma is easily treated if detected early however once vision is lost due to glaucoma it cannot be recovered.
• Approximately 350,000 people in the UK suffer from glaucoma. Its prevalence increases with age.
• Glaucoma can run in families, people with a direct relative with glaucoma i.e. brother, sister, parent or child have a 1 in 10 chance of developing the condition themselves.
• People over aged 40 with a direct family relative with glaucoma are entitled to an annual eye examination paid for by the NHS.

There are two main types of glaucoma:

Primary Open Angle Glaucoma

• This is the most common type.
• It is a silent condition. The patient generally has no symptoms.
• A gradual increase in intra ocular pressure leads to damage to the optic nerve and loss of peripheral vision.
• Treatment is very successful now using eye drops. Occasionally surgery is required where drops alone are not sufficient.
• This is the type of glaucoma we screen for in routine eye examinations.

Angle Closure Glaucoma

• Much less common.
• Generally the patient will have symptoms including an extremely painful red eye which may lead to nausea and vomiting, blurred vision and  coloured haloes around lights.
• Treatment for this type of glaucoma generally involves treatment with laser or a small surgical procedure.
• We also check for risk factors associated with this condition in our routine eye examination.

• The macula is the area of the retina responsible for giving us fine detailed vision.
• In Age related Macular Degeneration also known as AMD, this area of central vision is damaged, this causes a reduction in detailed vision leading to difficulty reading or identifying faces for example.
• AMD generally affects both eyes, often one more than the other.
• AMD is the most common cause of low vision in the over 60's.
• AMD does not lead to complete blindness, the peripheral vision is not affected and so most patients maintain enough vision to get around and manage day to day tasks.

There are 2 types of AMD, Dry and Wet

Dry AMD

• Most common form.
• Patients notice a gradual reduction of the detailed central vision  and commonly find close tasks such as reading more difficult.
• There is no medical treatment for this type of AMD but magnifiers may be of help.

Wet AMD

• Less common, accounts for 10% of people with AMD.
• Usually quick onset.
• Patients may notice straight lines appear bent or vision is distorted.
• There is a build up of fluid under the macula, this may lead to scarring of the central retina.
• Medical treatments consists of laser and injections.

There is ongoing research into how nutrition affects the onset and development of AMD. These supplements cannot restore vision but may slow development of the condition.

For more information on AMD visit the Macular Society website.

The back chamber of the eye is filled with a gel called vitreous. With age the gel can become more liquid causing "Floaters". This process can also put tension on the retina causing "Flashes".

Floaters

• Usually seen against a bright background such as the sky on a sunny day or a white wall or page.
• Relatively common.
• Those that are present for many years without change are generally harmless.
• Floaters which appear suddenly or suddenly increase in number may indicate other problems within the eye and should be investigated urgently.
  

Flashes

• These may occur when the vitreous pulls on the retina.
• They last for a second like a lightning flash or sparkling light in the vision. They are different to the more prolonged shimmering lights seen in migraine.
• Flashes are generally seen in the dark and occur with eye movement.
• Sudden onset of flashes can indicate retinal problems and should be investigated urgently.

The majority of colour vision defects are inherited. The most common red-green deficiency affects 8% of males and 0.4% of females. Occasionally colour vision defects are acquired later in life due to eye or brain disease or the long term use of some medications.

People born with colour vision defects generally adapt and are often unaware of the defect until colour vision screening is performed. There is no treatment for colour vision defects, in some cases tinted lenses may be used to help distinguish between colours but nothing will allow the sufferer to see colours normally.

Acquired colour vision defects can occur gradually e.g.cataracts which lead to difficulty distinguishing blue colours. Generally more severe acquired deficiencies are associated with other visual symptoms. Many acquired defects are reversible when the underlying condition is treated.

Some occupations have colour vision requirements, we will be pleased to advise you on this.

What causes it?
There are many causes including age related changes, arthritis, central heating or dry, dusty working conditions.

What does it look like?
Often the eye is normal to look at, but symptoms include:

• Gritty, scratchy sensation in the eyes
• Itching
• Burning

How can I make it better?
Artificial tear drops can be used during the day, and ointment can be used last thing at night. Different types of artificial tear drops such as Thealoz and Hyabak can be bought from us over the counter without a prescription.
You should use the drops often at first, and you can gradually decrease the drops to just a few times a day to keep your eyes comfortable. You will be able to judge yourself how often you need to use them.

What happens next?
The drops will relieve your symptoms, but will not cure your condition, you will probably need to continue to use the artificial tear drops.
In some cases a minor operation on the tear ducts can help to retain tears in the eye for longer, thus relieving the dry eye and reducing the need for the drops.

It has been shown that a good diet full of fresh fruit and vegetables can play an important role in maintaining eye health, however we all know that eating 5 portions of fruit and vegetables every day isn’t always easy.

Ocuvite & Macushield dietary supplements for the eyes contain high potency antioxidant vitamins and zinc. Research has shown that vitamins help maintain healthy issues with the eye. Ocuvite also contains lutein a special antioxidant which helps protect the macula.