Answer: The term parameters refers to the way your contact lenses fit on your eye – the curvature, diameter and power of each lens. Because everyone’s eyes are different, it is important to ensure that the contact lenses you wear are comfortable.
What are the properties of contact lenses?
Together with other material and surface properties, such as toughness, creep, surface friction, and wettability, the lens manufacturer has considerable flexibility to design a lens that performs well on the eye in vision, comfort, and physiological health.
How are contact lenses measured?
Generally, your eye doctor will use a keratometer to measure the curve of your cornea, which is the front surface of the eyes – where contacts rest. These numbers help to determine the lens diameter and base curve that appear on your contact lenses prescription.
What is the range for contact lenses?
All Contact Lenses contact lenses
|Contact Lens Name||Power Range||Diameters|
|1 Day Acuvue TruEye||+6.00 to -12.00||14.2|
|Acuvue 2||+8.00 to -12.00||14.0|
|Acuvue Advance||+8.00 to -12.00||14.0|
|Acuvue Advance For Astigmatism||+6.00 to -9.00||14.5|
What is DIA and BC in contact lens?
Base Curve (BC): the number that indicates your contact lens’ shape. According to the steepness or flatness of your cornea, your prescription indicates how large your contact lens should be. 2. Diameter (DIA): a number indicating your contacts’ length to make sure they’ll cover your cornea properly.
Which material is best for contact lenses?
Silicone is the name used to describe plastic materials with a gel-like consistency that contain silicone, as well as oxygen, carbon and other elements. It’s an extremely flexible material, which makes it excellent for making not only contact lenses, but many other medical products such as implants and tubing.
Which contact lens material is best for eyes?
Silicone hydrogel contact lenses are now the most popular type of contact lenses. Gas permeable lenses. Also called GP or RGP lenses, these are rigid contact lenses that maintain their shape on the eye, enabling them to correct astigmatism and other refractive errors.
What does D mean on contacts?
Sphere (SPH): The amount of lens power, measured in diopters (D), which corrects nearsightedness or farsightedness. If the number under this heading features a minus sign (–), this means you’re nearsighted; if it has a plus sign (+), this means you’re farsighted.
What is the difference between 14.0 and 14.2 diameter contacts?
14.0mm and 14.2mm contacts
In fact, there is not much difference between these two. Some manufacturers only make 14.2mm diameter contacts, and some others produce 14.0mm diameter contacts. … Many 14.0mm contacts users use 14.5mm or 14.8mm contacts to demonstrate dolly effects on their eyes.
How do I know my eye diameter?
For accuracy and consistency, always measure from the white part of one side of the eye directly across to the white part of the other side of the eye. Reference the example image below; the corneal diameter or visible iris diameter measures 12.01mm.
What does 8.4 mean on contacts?
A BC of 8.4 mm of radius is more curved, and therefore a tighter fit, than 8.8 mm base curve. People who have steeper corneas require tighter fitting contacts. If a contact is too loose, it may be uncomfortable, fold, or come right out.
How do I know my contact lense power?
You’ll find that the cylinder number on a contact lens prescription is always a minus number. This indicates the extra power you need for astigmatism correction. A higher number denotes a more severe level of astigmatism. The cylinder value for a glasses prescription on the other hand can be a plus or minus.
What is the strongest contact lens?
What is the strongest contact lens prescription? Contact lenses can be prescribed for extreme degrees of myopia, even for those who need correction of more than -20 Dioptres. Some lenses can go over -30 Dioptres. For monthly soft contact lenses, the highest level of corrective power is about -12 Dioptres.
What is SPH and CYL and axis?
Website Form. Type 1: Spherical (SPH) Only Power. 60% people have only spherical (SPH) power with no Cylinder (CYL) and Axis (AXIS) Note: For making these specs, we do not need other information of your prescription such as 6/6 or 6/4 or PD (pupillary distance) Type 2: Spherical with Cylinder (CYL) Power.
What is normal BC for contacts?
Typical base curve values range between 8.0 and 10.0 mm, though it can be flatter (from 7.0mm) if you have a rigid gas-permeable lens. A person with a higher base curve number has a flatter cornea (the clear, front surface of the eye) compared to someone with a lower base curve number, which indicates a steeper cornea.
What does axis mean for contacts?
The axis indicates the angle (in degrees) between the two meridians of an astigmatic eye. The axis is defined with a number from 1 to 180. The number 90 corresponds to the vertical meridian of the eye, and the number 180 corresponds to the horizontal meridian.