High-Definition (HD) Vision
By now, we have all at least heard of, if not seen first hand, high definition Television. HD TV provides the clearest images, almost too clear showing imperfections and other abnormalities of our favorite movie stars.
Watch High Definition TV with High Definition Vision
Many of our glasses can actually prevent us from seeing the very best due to higher-order aberrations. These aberrations are imperfections, or small blurred zones, your natural eye makes by the way that light actually travels through your eye and the lenses we have in our glasses.
Eyeglass prescriptions are made in powers called diopters. A diopter is a measurement of lens power. So the higher the diopter power, the stronger the eyeglass prescription is. Opticians grind the power of the Optometrists’ prescription into lenses and then shape those lenses into your eyeglass frame. Lenses can be made from
i) glass: (great clarity, but heavy, dangerous if cracked or chipped or shattered, difficult to scratch)
ii) polycarbonate: (clarity, impact resistance-will not shatter, protects against UV light and are very light weight)
iii) CR39 plastic : (good clarity, light weight, easily scratched, easily warped)
iv)Trivex: (excellent clarity, shatter proof, protects against UV)
The higher the diopter power of your prescription the thicker the lenses become. They can be thinned down by using high index of refraction lenses. However, even the thinnest lenses can have imperfections that you and I cannot see in the lenses, that cause light to travel differently through the lenses. We call this scattering of light through the lenses, higher order aberrations. This picture shows what higher order aberrations can look like.
As you can see both prescription lenses can provide very clear vision. The image on the right is much “higher definition”. Look carefully at the headlights of the vehicle and the speed limit signs. High definition lenses provide much better vision and clarity.
High Definition Prescription Lenses
Also known as “free form eyeglass lenses” or “digital lenses”, is a more advanced way of making prescriptions eyeglasses that can reduce the scattered light that comes through prescription lenses (also known as higher order aberrations).
Standard lenses are converted to prescription lenses by hand grinding curves into the lenses. Digital lenses use computerized technology to precisely grind prescriptions into the lenses. Because everything is computer controlled in the making of high definition lenses, prescriptions are much more accurate.
Diopters are measured typically in .25 increments. However your doctor can measure your vision in increments of 0.01 steps. So if your Prescription measures for example -2.12 with standard lenses you would receive a power of 2.25 or 2.00. Both would give good vision.
However, at -2.12 (your actual prescription) you would have great optimized vision. In addition to making the lenses more precise, like a custom tailored suit vs a suit off the rack, when we measure your frames on your face we measure the distance each eye is in the center of the frames to make sure your eye’s rotation is directly in the center of the frame. Now the center of the prescription lens instead of being estimated, can be customized for both your right and left eyes, providing the sharpest vision possible.
As you can see with the lady above, her pupil height may be slightly different between the right and left eyes.
With digital lenses they can make the pupil height exact for each eye, providing the sharpest vision with the least amount of scattered light.
All of these precise additional measurements by our optical team provide the sharpest vision with least amount of glare or halo like vision, and the best side vision.
At times, special measuring devices are used for aligning your frame choice and custom lenses.
Who is a Candidate for High Definition Digital Lenses?
Anyone wearing glasses and wanting the most optimized clearest vision, is a great candidate for high definition digital lenses.
· Those with higher prescriptions may notice the most difference in terms of clearer, sharper, less glare vision with high definition digital vision
· Patients who never seem to "see clear” with an updated prescription
· Children with one eye not seeing as well as the other
· Patients spending a lot of time on the computer or tablet
· Patients with poor night vision compared to day vision
Cost of high definition digital lenses.
The high technology computerized equipment used to make free-form high definition digital lenses and the added time and equipment needed to align and fit them adds only about 25-30% more to the fees of these lenses. Keep in mind, these lenses come with all the treatments that are usually “add-ons” to standard lenses.
Nearly everyone who has tried high definition digital free form lenses compared to standard lenses find their vision with a noticeable improvement in clarity and comfort.
Stop by Primary Eye Care Associates for a complimentary demonstration on the benefits of high definition digital free form lenses for yourself or child.
Design your own lenses here before your next appointment by visiting www.choosemylens.com.