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The first step toward creating personalized eyewear occurred in the early 2000s, when digital and free-form spectacle lenses hit the market. Among the first to market were Zeiss, Rodenstock, Seiko, Shamir, Hoya and Essilor.

Using digital surface generators powered by free-form technology developed by companies such as Schneider Optical Machines, Satisloh and OptoTech, and advanced lens calculation software from DVI, VisionStar, CC Systems and others, the lens makers created sophisticated new ways of shaping both the front and back lens surfaces. The resulting lens designs allow new opportunities for wearers and opticians alike.

There are three main sub-categories of digital and free-form progressives (PALs): optimized, customized and personalized, often referred to as good, better and best.

(Good) Optimized—An optimized digital lens employs proprietary software, combined with CNC lathes to customize thousands of points across the lens surface using default fitting data. Required fitting measurements: monocular PDs and segment heights.

(Better)—Customized PALs incorporate all the benefits delivered by the optimized design, with additional enhancements using actual measured Position of Wear (POW) data. Required fitting measurements: monocular PDs, segment heights, lens tilt, wrap angle and vertex fitting distance.

(Best)—Personalized, digital PALs incorporate all the above, but individualize the lens using designs that are more task specific, and/or incorporates biometric data like aberrometry analyzed prescriptions, or values from proprietary fitting instrumentation such as eye center of rotation distance, head or eye turning ratios, or the effects of the dominant eye.