You are likely to encounter some optical terms during the process of selecting your glasses. Here at BargainSpecsDirect, we have picked a few of the most common terms and expressions and added straightforward explanations.

We hope this will help you understand better what some of these optical expressions really mean and that it helps you feel more comfortable ordering your glasses direct from us.

Hypermetropia / Hyperopia

Hypermetropia or Hyperopia results from light rays not being fully focused by the time they reach the retina, due to the eyeball being too flat or too short to suit its optical system. 
 

• Distance vision is generally good
• Near Vision is more difficult or blurred
• Younger people often have good distance vision
• As you get older distance vision becomes more difficult

Myopia

Myopia is the reverse condition of Hypermetropia or Hyperopia. In this case, the eye is too long for the optical system. It results in trouble seeing objects at a distance and only near objects can be seen clearly. 

• Distance Vision is blurred
• Near Vision is clear

Astigmatism

Astigmatism is a very common condition and is nothing to be overly concerned about. It is uneven curvature of one of the eyes optical surfaces. Typically, the front of the eye is not spherical like a football but is more the shape of a rugby ball.

• Both distance and near vision can be blurred
• Even small amounts of astigmatism can cause discomfort when reading or using a computer

Presbyopia

Presbyopia is a vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult for you to focus on close objects.

• Affects people from about the mid-forties
• The muscles and lens in the eye become less flexible due to aging
• Near vision becomes more difficult and spectacles are needed for close work

Squint

A squint (also known as strabismus) is a condition that arises because of an incorrect balance of the muscles that move the eye, faulty nerve signals to the muscles and some refractive error (focusing faults). If these are out of balance, the eye may turn in (converge), turn out (diverge) or sometimes turn up.

• Commonly found in young children
• When one eye turns and does not work properly with the other
• If one of a pair of muscles is weak a squint can occur
• A squinting eye may not develop properly leading to a 'lazy' eye
• Often an operation, followed by exercises, can remedy the squint
• Early diagnosis is important.

Cataract

If you have discovered that you have a cataract, don't worry! More than 50% of those over age 65 have some cataract development and the majority can be treated successfully with surgery. A cataract is a clouding of part of your eye called the lens. Your vision becomes blurred or dim because light cannot pass through the clouded lens to the back of the eye.

• As you age the lens inside the eye can become cloudy.
• A reduction in the standard of vision even with spectacles
• Haze around lights especially at night
• Glare in bright sunlight
• Becoming less longsighted or more short sighted
• When cataracts begin to restrict vision they can be removed and the lens of the eye replaced with a small plastic lens inside the eye. This is now a relatively straightforward procedure with a very high level of success.

Glaucoma

The front part of the eye contains fluid called 'aqueous humor.' This fluid normally drains away through a sieve-like structure inside the eye called the trabecular meshwork. If this meshwork becomes clogged up for any reason, the fluid cannot escape and pressure will build up inside the eye. This will result in pressure on the optic nerve and, consequently, sight in the eye is permanently lost. This disease is called 'glaucoma'

• Glaucoma is the result of the pressure within the eye increasing until, if undetected, it causes a loss of vision.
• In chronic Glaucoma, by far the most common type, there are no symptoms until visual loss is experienced.
• Glaucoma affects 2% of the population over 40 and if a person has a close relative who suffers from the condition they then have a higher risk of developing the condition.
• During a routine eye examination all people over 40 will have the pressure measured to ensure that it is within normal limits.
• Where Glaucoma is diagnosed treatment can reduce the pressures and prevent the onset of visual loss.

Age Related Macula Degeneration (ARMD)

AGE-related macular degeneration (ARMD) is Britain's biggest cause of blindness, affecting up to 700,000 people over 65. It's caused by a build-up of deposits in the macula, which is made up of millions of light-sensitive cells. Symptoms include blurriness and dark or empty spaces blocking vision.

• ARMD is the greatest cause of visual loss in people over 60
• There are two types of ARMD :
• Dry – The most common form of the condition where the macula (the area at the centre of the retina at the back of the eye which is responsible for detailed vision) gradually breaks down as part of the aging process. There is no treatment for this condition but it tends to progress slowly
• Wet – The rarer form of ARMD where there are changes in the blood vessels in the macula area. This form tends to move quickly and where detected early it is possible in some cases to arrest the progress

Diabetes

Although a general condition Diabetes can in some cases affect vision.

Diabetes mellitus or `sugar diabetes' affects about one person in fifty in the UK. This means that the body cannot cope normally with sugar and other carbohydrates in the diet. If you have diabetes this does not necessarily mean that your sight will be affected, but there is an enhanced risk. If your diabetes is under control then you are less likely to have problems, or they may be less serious. However if there are complications which affect the eyes then this can result in loss of sight.

• It can affect the lens of the eye with the result that the optical prescription can change over a short period of time
• Cataracts can form earlier and more quickly
• Changes in the blood vessels at the back of the eye can affect the vision

It is for this reason that all diabetics are advised to have regular eye tests.