Contact lenses problems

Contact lenses are worn by more than a million people in the UK and are a popular form of corrective device for defective vision. They are worn by people with myopia (short sightedness), hyperopia (long sightedness) and astigmatism and are considered a handy alternative to glasses.

Most people who wear contact lenses do not experience any problems with them but there are others who develop an eye condition, for example conjunctivitis.

Poor hygiene or lens care is often the reason for eye problems. But there are a few minor risk associated with contact lens wear which you need to be aware of.

These are either problems with the actual lenses or an eye infection.

Lens problems

Problems with the lenses themselves include:

• Poorly fitting lenses
• Damaged lenses
• Failure to care for lenses
• Dry eyes

Poorly fitting lenses

Lenses which are not a suitable fit or are too tight will quickly become uncomfortable and lead to a condition called ‘tight lens syndrome’.

Damaged lenses

Soft contact lenses are fragile things which are easily torn or damaged. Chips and cracks are not uncommon and more of a problem than with gas permeable lenses.

Another problem is that of a misshapen lens, usually from squeezing it too tightly when cleaning it or from leaving it in hot temperatures.

Failure to care for lenses

This is usually the cause of most contact lens problems. Many people fail to realise the importance of cleaning their lenses properly and on a regular basis. This allows protein deposits to build up on the lenses which cause irritation of the cornea and impaired vision.

It is also important that contact lenses are handled with care and kept away from other substances such as cosmetics, hair care products and food. Contact with these can damage the lens which then leads to eye infections.

Dry eyes

This is often caused by staring at an object, e.g. a computer screen, for long periods of time. Plus contact lenses reduce your ‘blink rate’: the rate at which you blink your eyelashes which helps to remove any deposits from the eyes.

They also reduce the amount of tears produced by the tear duct glands which help to keep your eyes moist and lubricated.

If you are prone to dry eyes then it is possible to purchase contact lenses which are specially designed for dry eyes. They reduce this dryness by maintaining a layer of water around the lens which means that they stay moist and comfortable to wear.

Eye conditions

Then there are various eye infections/conditions which include:

• Conjunctivitis
• Corneal abrasions
• Keratitis
• Corneal hypoxia
• Tight lens syndrome
• Viral infections

Conjunctivitis

There are several different forms of this eye condition which include allergic conjunctivitis, keratoconjunctivitis and toxic conjunctivitis.

The allergic variety is caused by an adverse reaction to a substance used in contact lens solutions. This causes itchy, red, sore eyes.

Keratoconjunctivitis is the medical name for inflammation of both the cornea and the conjunctiva. This causes an itchy, burning sensation in the eye and problems with vision. It sometimes occurs in people who wear soft hydrogel lenses.

Toxic conjunctivitis develops due to the cleaning solutions used for contact lens care: or by allowing the lens to come into contact with a substance on the hands at the time of insertion.

Corneal abrasions

These are small but painful scratches which develop on the surface of the cornea. They can occur if a contact lens is worn for longer than the recommended duration or you rub your eyes whilst still wearing your lenses.

Keratitis

This often occurs as a result of dry eyes. The cornea becomes inflamed as a result which causes pain, redness and blurred vision. It may be caused by the insertion of a damaged or cracked lens into the eye which then rubs against the cornea, leading to a scratch.

There are two forms of keratitis: microbial keratitis and superficial punctate keratitis. Microbial keratitis is the more serious of the two and can lead to serious damage to your eyesight.

Corneal hypoxia

This is less likely to occur nowadays due to improvements in contact lens technology. It is caused when insufficient oxygen passes through to the eyes which lead to swelling, light sensitivity, pain and problems with vision.

This tends to affect people who use extended wear lenses or use them beyond the recommend amount of time.

Tight lens syndrome

This develops in people who wear gas permeable lenses or the continuous wear variety which can be worn overnight. The lens appears to be fixed on the cornea and does not glide across it even on blinking.

This causes pain, irritation and blurred vision.

Viral infections

It is possible to develop a viral infection such as Herpes from wearing contact lenses although there is no proven link between these two. If you develop an infection then throw away any lenses worn during that time and wear new lenses once the infection has cleared.

It is a good idea to give your eyes a break during this time and only resume wearing your lenses once you are free from infection. Do this for any other type of eye problem such as keratitis.

Contact your optician or contact lens practitioner for advice.

Other problems

Dry eyes are a problem but can be easily solved. You may need to use eye drops or switch to a pair of contact lenses which are specifically designed for dry eyes.

The cause of this is not enough oxygen reaching the eye: the more oxygen that reaches the eye the better this is for the health of the eye. It also means crisp, clear vision.

Gas permeable lenses are better at the transmission of oxygen to the eye due to the materials used in their production. They allow a greater volume of oxygen to reach the eye as compared to soft lenses.

Soft lenses may be more popular but they are made from water based materials which means that they have a tendency to dry out. This can prevent enough oxygen from reaching the eye which leads to eye infections.

Other problems include allergies to the cleaning solutions, lenses which become ‘lost’ in the eye and computer vision syndrome.

Awareness of potential eye problems

Contact lenses do not cause many problems and serious conditions are rare. But a problem can develop which you may be unaware of which is why it is important that you have regular check ups. Don’t forget to have a regular eye test either!

Follow any instructions carefully and do not wear your lenses any longer than advised to or wear them at night (unless they are the continuous wear variety).

Ask your optician for advice.