Do you have 20/20 vision when you wear your glasses but still feel dissatisfied with how you see? You might benefit from high-definition lenses.
Sometimes, higher-order aberrations can affect your vision, even if your prescription eyeglasses fully correct your nearsightedness, farsightedness and/or astigmatism. These aberrations may be due to the optical characteristics of your eyes or can be caused by the optical limitations of conventional eyeglass lenses.
But recent advances in eyeglass lens manufacturing have made possible new high-definition eyeglass lenses that correct these aberrations, potentially giving you sharper vision than what is possible with conventional eyeglasses. These lenses are designed to provide sharper vision in all lighting conditions and reduce glare for nighttime driving and other night vision tasks.
Many brands of high-definition eyeglass lenses currently are available, including high-definition versions of high-index lenses and progressive lenses.
The most popular type of high-definition eyeglass lenses are called free-form lenses. The term “free-form” refers to an advanced manufacturing process that reduces higher-order aberrations such as spherical aberration that occur in eyeglass lenses created with traditional eyeglass lens manufacturing tools and processes.
With free-form lenses (also called digitally surfaced eyeglass lenses), the fabrication of the lenses from wearer’s eyeglass prescription is optimized with advanced manufacturing tools (“surfacing” equipment) that are much more precise than conventional tools. In fact, digital, free-form technology can surface lenses in power intervals of 0.01 diopter (D), compared with 0.125 to 0.25 D increments of conventional eyeglass lens tooling.
The fabrication of some digital, free-form lenses also takes into account how the lenses are positioned in front of the wearer’s eyes when in the eyeglass frame when optimizing the lens power.
Other factors that may be considered in the lens customization process include the angle between the eye and the back surface of the lens in different gaze positions (for example, when the wearer is looking off to the side rather than straight through the center of the lens), the frame size and the position of the wearer’s pupil within the frame outline.
With these and possibly other factors taken into account during lens design and fabrication, high-definition eyeglass lenses offer an unprecedented degree of customization and may reduce or eliminate certain higher-order aberrations.
The precisely made and personalized surfaces of high-definition lenses may help reduce aberrations that limit field of view and cause starbursts, halos and comet-shaped distortions of lights at night.
The result is that high-definition lenses may provide sharper image quality, better peripheral vision, improved contrast sensitivity and less glare at night.
Continue Reading article By Gary Heiting, OD on All about Vision