About Contact Lenses
Masterlens Ltd. offers only quality lenses from top manufacturers such as Johnson & Johnson, CibaVision, Cooper Vision and Bausch & Lomb. All products are recently manufactured with long shelf life and are sourced directly from the manufacturers or one of their authorized distributors.
Silicon hydrogel lenses
Silicon hydrogel lenses admit far more oxygenand are approved for wearing while sleeping for up to a maximum of 30 days (see also extended/continuous wear lenses). The majority of opticians now recommend only silicon hydrogel lenses for all-day use, since they are significantly safer than older types of all-day lenses.
Coloured lenses
The correct type of coloured lenses depends on eye colour and the result desired. Those with naturally light eye colours obtain the best results by using a lens that enhances their natural eye colour. Those with naturally dark-coloured eyes see the best results by using opaque coloured lenses, so that their natural colour doesn't show through and overpower the new colour. For optimal results, consult an optician.
Marking In & Out
Marking In & Out appear as letters or numbers on the lens for indoors-outdoors indication.
Visitint lenses
Visitint Lenses are visibly tinted lenses for ease of handling.
Bifocal lenses and Progressive lenses
The most common progressive lenses have a gradually stronger power towards the centre. This enables clear vision at both long and short distances known as simultaneous vision. Bifocal lenses also provide simultaneous vision. They have different zones in the central part of the lens for vision at long and short distances.
Toric lenses
Toric lenses correct a type of diffraction error known as astigmatism.
Extended wear (continuous wear) lenses Continuous wear lenses admit extra oxygen to the eye (cornea) and allow extended use 24-hours a day for up to one month without irritating the eye (Purevision, Air Optix Aqua Night & Day, Biofinity). Acuvue lenses are approved for wearing while sleeping, although for only up to a maximum of 6 nights. If you wish to change to extended wear contacts you must consult a qualified eye care practitioner.
Contact Lens Parameters
You can find your parameters on the paper copy of your prescription, or on the box containing your lenses. You will find details of the power/strength/sphere (SPH/PWR/P/D), base curve (BC) and diameter (DIA). If you have astigmatism you will also find an axis (AX or AXIS) and cylinder (CYL). If you use bifocal, multifocal or progressive lenses, you will find the extra strength or "add power".
Eye Power (PWR, SPH or D)
The Eye power is the number that measures your vision problem. It should be a number between -20 and +20. Numbers ranging from -0.25 to -20 indicate myopia; numbers ranging from +0.25 to +20 indicate hyperopia . 0.00 indicates no vision correction (often used for cosmetic/colour lenses).
Eye Axis (AX)
An axis is one of the values or measurements used to describe toric lenses. Toric lenses are used to correct astigmatism, a condition marked by unevenness of the cornea.
Extra strength (ADD)
Add power describes the difference in strength between the focal fields in multifocal and bifocal lenses.It should be a number between +1.00 and +3.00) or a value for low, medium, high.
Base curve (BC)
or radius It indicates the internal curve of the lens. It should be a number between 8.0 and 10.00.
Diameter (DIA)
The diameter is the size of the lens measured from edge to edge.and should be a number between 13.0 and 15.00.
Cylinder (CYL)
It indicates the degree of astigmatism on toric lenses, a condition marked by unevenness of the cornea. It should be a number between -0.25 and -10.00.
