Types of Lenses

 

Hard Lenses

 

Hard lenses are made from clinical quality perspex.  Oxygen will not pass through this material and the oxygen

demands of the front of the eye (cornea) must  therefore be satisfied by tear exchange behind the lens.  Because of

this, the build up of wearing times is fairly slow as the cornea adapts to the slight lack of oxygen.  Generally

unpopular due to poor oxygen transmission Patients who would benefit from a rigid lens will more likely use gas

permeable.

 

Gas Permeable

 

Gas permeable lenses are made from modern plastics which allow oxygen to pass through the lens.  In this way,

the problems due to the lack of oxygen associated with hard lenses are virtually eliminated.  Some patients, such as

those with astigmatism, may achieve better vision with a rigid lens.

 

Soft Lenses

 

Soft lenses are made from hydrophilic plastics which absorb water to become flexible.  It is the water content of

the lens that allows the oxygen to pass through.  The higher the water content, the greater the permeability.  They

require much less adaptation time due to their initial discomfort.  This permits more flexible wearing schedules

such as social / weekend wear.  Also available in tinted designs, astigmatic prescriptions and even bifocals.

 

Silicone Hydrogel

 

A special type of soft lens with higher oxygen transfer then traditional soft lenses.  Perhaps surprisingly they

have low water contents, but their high silicone content allows gases to pass easily.  These new materials

are currently only available in a few different designs, but may represent the future of contact lenses.

 

Lens Choice

 

Most new contact lens wearers opt for soft lenses.  By using ‘Regularly Replaced’ or ‘Disposable’ soft lenses

it is possible to avoid the problems of durability and complex multi-stage cleaning systems.  It often allows

lenses to be provided from stock, and payments to be made by monthly standing order to spread the costs

whilst covering all aftercare appointments.

 

There are many options - It should be possible to find a lens type / replacement frequency / solution package

to suit you.

 

It may help to ask yourself a few questions;

 

How many days a week do you think you will wear contact lenses?

 

Less than three is occasional, more than five is regular.

 

Do you find cleaning lenses time consuming?

 

Hygiene is very important, however, it may be possible to use a simpler cleaning system combined with

more frequent replacements - or maybe you could try daily disposables.

 

Do you work in a dry office and find contact lenses uncomfortable?

 

Perhaps a change in lens material would help.

 

Are you a little older now and require a separate reading prescription?

 

Bifocal contact lenses are available for frequent replacement, we even have trial lenses in stock!