We live in an age of technology which is expanding at an alarming rate, affecting every aspect of our lives. One of the biggest advancements in technology is not what we carry in our pockets, wear on our wrist, or keep in our homes; it’s what we wear every day on our faces—our glasses. Digital lens technology has redefined how people see, by introducing a new level of customisation for people who wear glasses. Digital lens processing, also known as freeform or high-definition, has resulted in many lens advancements since its introduction a few years ago. For the first time, the wearer can receive a corrective lens designed expressly to accommodate his or her prescription, rather than having to use one of the lenses available in a lens inventory.

How do digital lenses work?

The primary benefit of digital lenses is that they are custom made exactly to each prescription. Conventional lenses are partially premade by lens manufacturers, and when prescription lenses are produced, a laboratory selects from among the premade materials whichever is most appropriate, and then grinds the prescription as closely as possible into the material. The result is a lens which is satisfactory, but not perfect.

While there is only a slight difference in ordering digital lenses as opposed to old technology lenses, there is a lot of high-tech work that goes on behind the scenes. The lens material is not necessarily different; it is the way they are processed that makes the difference.

After examining your eyes and establishing the prescription you need, your optometrist will take a series of measurements. Digital lens measurements are extremely precise and measure not only unique characteristics of your eyes but also how your eyes are positioned in your chosen frame and how that frame fits your face.

From there, the lenses are sent to a laboratory. Your prescription is digitally mapped onto lens blanks and diamond cut with sophisticated, laser-guided machines. This high-end technology ensures a higher level of accuracy than the traditional abrasive-ground lenses, resulting in greater visual comfort and clarity, particularly in peripheral vision which is often compromised with traditional lenses.

The benefits of digital processing are more significant when astigmatism is involved. To correct astigmatism lenses have two prescriptions ground into them at cross directions. Since every unique prescription requires a unique curve, lenses that correct astigmatism require two unique curves. Digital technology enables perfectly accurate curves for both prescriptions to be groundinto the lenses, giving high astigmatism patients better vision than possible with conventional lenses.

Position of Wear

Clear vision depends not only on the lens itself, but also on the distance the lens is from the eye, as well as the tilt and angle of the lens relative to the eye. The prescription from the optometrist assumes a final lens that sits at the same distance from and angle of tilt relative to the eye as the lens in the examination room. But there is a large variety of frame shapes, sizes and angles that do not replicate the examination room lens position, so that aconventional lens will not exactly reproduce the vision experienced in the examination room.

With freedom from the constraints of conventional lenses and the precision of the technology, digital lenses can be customised taking into account information on the position of wear of the glasses. The result is a lens perfectly designed to a patient’s prescription in a particular frame, which fits that patient’s face, creating examination room vision.

Are you protecting your eyes?

As well as offering a high level of customisation, another benefit of digital lenses is that they can protect your eyes from your digital life. With the amount of time we spend in front of digital screens every day, it may be worth considering computer vision lenses to help relax the eyes and minimise digital eye strain. Computer screens emit a harmful blue light that can, over time, damage your eyes and cause diseases like macular degeneration. Digital lenses can be specially formulated to filter out harmful light and sharpen contrast.

Who Should Wear Digital Lenses?

Anyone can wear digital lenses, but some patients will get more benefit than others, and some will perceive no difference. Patients with mild corrections, in frames that are fit at a proper distance from the eye with a moderate tilt and wrap, will experience little advantage from digital technology. As prescriptions increase in power and complexity, and frames deviate from “classic” fitting parameters, conventional lenses will have more error and digital technology becomes more beneficial. Conventional lenses do fail to exactly replicate examination room vision, but for some prescriptions and patients the degree of error is so low that the perceived difference between the conventionally corrected vision and digitally customised vision is zero, and the benefit of digital lenses will not be experienced. When the frames deviate far from the classic fit parameters or when prescriptions are strong or have higher astigmatism, that's when digital lenses can provide crispness and clarity of vision never before possible.

As always, rely on the judgement of your optometrist, who will counsel you on the particular benefits of digital lens technology for your needs, and ensure that you always get the best vision possible