It is known that contact lenses are made of the soft or rigid material and they come in different sizes and curvatures. The prescription of contact lens is based on the specific measurement of your eye and it is matched to the certain specifications and also measurements of the contacts. There are several types of equipment and methods that are used for measuring contact lenses. Just check out the following tips for knowing how to measure contact lenses.
The first thing that you should do is to use PD stick or the optical ruler for measuring the diameter of the lens. The measurement will be recorded in millimeters. Most of the contacts commonly range from 8 to 14 millimeters across.
The second thing is to measure the curve of the lens by using lens clock. Lens clock is known as an optical instrument which measures the base curves of both contact lenses and eyeglasses. The base curves on the contacts are created to match the curvature of the cornea. If the number is lower, the curve of your cornea will be steeper.
The third thing is to use lensomter. Lensometer is known as s standard piece of the optical equipment that used for measuring the strength of the lenses. However, only certain types of lensometer which has the ability for measuring the prescription power of the contact lens so that you should ensure that you are using lensometer which measures the contacts.
The fourth thing is to measure the toric contact lens that should be done by checking the orientation makings of the lens while the lens is on the eye. These kinds of special markings can help you to know whether your contact is in the right place on the eye in a way to correct for astigmatism. Usually, the marking are horizontally situated in the middle and at the outside part of the lens which is called "3 and 9 o'clock."
The last thing is to use wave front aberrometry. It is known that aberrometers are using light technology for measuring the overall power and defecting of the eye but they recently have also been used for measuring the contact lenses. In addition, the machine can work well by tracking how the light rays travel through contact lens.