You are unique – as is every other person. We all have our own personalities. Every eye has its own character, too – not a single one is identical to another. Only customized lenses can meet these special requirements. The more precise the examination of your eyes and your visual patterns by your eye care professional, the better your vision will be when you put on your new glasses.
What makes a lens unique? How much measuring data does it take to perfectly align the lens with your individual needs? And why will you enjoy more relaxed vision if you choose customized lenses?
Try this exercise: Cover half of your face with a mirror while standing in front of another mirror. Now your own face will look strange to you – unnatural, even. Not a single person on earth has two symmetric halves of a face. Even this minute detail plays a huge role in the extremely precise production of lenses because the highly sensitive human eye recognizes even the tiniest deviations. The long-term results could be visual problems or fatigue. It is therefore hardly surprising that your visual impression will be more comfortable and more relaxed if your lenses and frames are aligned accurately with your individual asymmetry and the shape of your face.
It is even more important to obtain such precise data if your lens is highly complex or powerful. The most exacting task is the production of progressive lenses where the transitions of the long-distance vision zone and the reading zone are cut into the lens invisibly. Customized production is of particular importance for these lenses so that the vision result attained is not impaired in the transition zone between distance and close-up vision.
Pupillary (or interpupillary) distance: Measurement of the distance in millimeters between the centers of the pupils in the right and left eyes.
Personal vision patterns: Have you ever consciously thought about the way you read a book or at which distance you hold your tools or needles while working? These measurements are critical for the customization of your personal lenses, as is your occupation (are you working at a desk or are you a craftsman who works outdoors a lot?). Another aspect to be considered is your hobbies.
Viewing height of the eye: The point where your left and right eye looks through the lenses also differ from eye to eye. These points are measured from the bottom rim of the glasses, i.e., the rim of the frame.
Frontal incline of the frame: Because everyone’s face is different, the frontal incline of the glasses will vary accordingly. Consequently, it is very important that this value is also considered in the calculation of your individual lens requirements.
Distance between the eye and the lens: This distance also differs from individual to individual. Experts call it the back vertex distance. Compare, for instance, the facial profiles of a European and an Asian. You will instantly recognize a difference with the naked eye.
Wrap of the frame: To adjust the glasses to your face, the frame is slightly concave. Experts call this the degree of wrap. It also has to be included in the precise calculation of an individual lens.