Modern Lens Design

_{Article first published: May 2023}

ZEISS SmartLife Individual 3 lenses offer the highest level of personalization available in a ZEISS lens. New scientific findings on visual behavior and the possibilities of digitalization form the basis for this individualization. Find out how modern lens design works.

Over the last 20 years, our lives have changed fundamentally. Digitalization became a big part of our everyday lives, smartphones have led to a complete shift in the way we work and function, and there has been a change in viewing behavior that extends across all age groups.

But just as daily life continues to change dynamically, research and development activities at ZEISS Vision Care and at the ZEISS Vision Science Lab, located at the University of Tübingen, continue to pursue the question of how to incorporate measurable changes in gaze behavior into the design and function of modern eyeglass lenses.

The more precisely the lens is adapted to the visual acuity and visual behavior of the eyeglasses wearer, the better the visual experience. So when it comes to manufacturing modern lenses, it is therefore enormously important to understand visual behavior and to deal with changing lifestyles and realities. This is the only way to create products that offer added value for eye care professionals and eyeglasses wearers. ZEISS researches human visual behavior in collaboration with various research institutions.

The international ZEISS Global Vision Study¹, examined in 2020/21, among other things, how life and thus (visual) habits have changed in today’s modern, connected and mobile world. To gain more precise insights into visual behavior, millions of data points were recorded on the daily lives of several hundred people in different countries. The subjects belonged to different age and occupational groups and had different social and cultural backgrounds. Data collection took place at home, at work, on weekdays and on weekends. This diverse data allows for a patient-centered approach that attempts to capture the actual reality of people's lives.

1. Age gives information about the visual needs
Regardless of age, interaction with digital devices has increased. Age-dependent similarities could be identified in the usage patterns. They allow us to dive deeper into the age structure and filter out age-specific details that make a difference. For illustration purposes, these were grouped into age groups.

2. Self-assessment not sufficient for detection of visual needs
For the calculation of a modern eyeglass lens, the visual behavior is a central parameter. It is made up of various factors such as the type of activity and eye movement. The increasing dynamics due to parallel and competing attentions and activities, for example, paying attention to the path and the smartphone at the same time while walking, makes this a complex task and complicates the self-assessment of the relative and absolute proportions of engagement.

3. Visual behavior is shaped by habituation
Comparing the study data with the data collected during the eye test, there is a difference between biological age and so-called ocular age or optometric status. This means that ocular status, visual needs, and satisfaction with a particular refraction are different than one would assume based on biology alone. These two factors must be considered to understand the spectacle wearer's habituation.

An important component of increasingly individualized eyeglass lenses is a deeper understanding of visual behavior and oculomotor function. The fact that scientific studies can provide increasingly diverse data and, above all, that this data is becoming usable, is also thanks to the technological progress of intelligent measurement methods. "What's important here are the special technologies that help us advance science and knowledge,” explains Lappe.

To be able to use the findings of the Global Vision Study 2020/21, more than 12 million data points were clustered and evaluated using Big Data tools. A specially developed algorithm, known as Intelligence Augmented Design (IAD) technology, now enables the information to be transferred to the design of ZEISS SmartLife Individual 3.

The known parameters for ordering a ZEISS SmartLife lens, such as prescription, wearer and frame parameters, reading distance and age, are transferred to the IAD algorithm. This defines vision requirements and then optimizes the decisive design parameters based on the calculated object model and design fingerprints.

Step 1: At the eye care professional’s, objective and subjective refraction is used to define the visual requirements and the appropriate lens. Here, all the necessary details for individualizing the lens are recorded: The frame data, the anatomical data such as the distance between the eyes, the refraction, and the type of lens: single vision, digital or progressive.

Step 2: The improved ZEISS SmartView 2.0 technology then forms the basis of the design: The technology considers the key elements of visual behavior and visual needs of people of all ages in today's connected, on-the-move lifestyle. In other words, the use of visual zones (near, intermediate, far), eye movements and head movements. This step already enables all-day comfortable vision at all distances and in every direction and is the basis of every ZEISS SmartLife lens.

Step 3: The individualization process starts here: The best fitting target for the lens design is created. This is done with the new IAD technology. In simple terms, the eye care professional's data – the specified lens type, the individual prescription, the wearer and frame data, and the person's age – are compared with the age-dependent visual behavior profiles in the database and appropriate optimizations are made. In this way, the optimal design target is selected.

Step 4: In this final step, all order parameters are used in an iteration process to adapt the real lens as closely as possible to the target design: The individual data of the spectacle wearer is thus considered in the calculation of the ideal lens surface. Once this step is complete, the final ZEISS SmartLife Individual 3 lenses are calculated, and the result is transferred to production.

The individualization of eyeglass lenses is not a new market trend. The continuously improved adaptation of eyeglass lenses to special visual needs can be seen as a result of technical progress. On the one hand, a different quality of data can be collected when conducting scientific studies, for example, through the use of eye trackers and other measurement sensors in the objective recording of oculomotor activity, i.e., eye movements and habitual visual behavior. In addition, computer-aided data analysis enables the processing and use of a much larger amount of data. On the other hand, intelligent algorithms help to bundle and analyze the findings and to translate them into concrete spectacle lens designs. The more precisely it is known how a eyeglass wearer looks through the lens with the respective spectacle frame, the more precisely the lens can be manufactured in such a way that it enables the spectacle wearer to see through it naturally. Optical vision support is thus received exactly where it is needed.

• With ZEISS SmartLife Individual 3 85 percent of wearers perceived wide fields of comfortable vision in all directions and at all distances.²
• 8 out of 10 wearers adapted to their new lenses very fast.²
• An up to 79 percent better match to visual needs and behavior.²
• New ZEISS SmartLife Individual 3 lenses give up to 29 percent better performance.^2,3
  

2010: ZEISS IndividualFit technology

As early as 2010, the customer's visual needs, visual behavior and lifestyle were taken into account in the lens design for the first time. No eye trackers were used for the ZEISS IndividualFit technology yet. Individual data on anatomy and lifestyle through questioning, led to a specific lens design.

2014: ZEISS DriveSafe lenses

With the introduction of ZEISS DriveSafe lenses, fundamental changes in lens design occurred in 2014. The lens performance is task oriented as it supports the visual performance of the spectacle wearer while driving. Simulators were used to study eye movements during driving. Thus, for the first time, the design of eyeglass lenses was improved based on objective data.

2015: ZEISS Individual 2

With ZEISS Individual 2, the design of the progressive lens is adapted to the individuals main daily activities. The choice of three lens designs suits the wearer's needs. Optimization for the near zone and activities such as reading. Optimization for balanced vision for activities at a wide range of distances. And the optimization for dynamic vision at medium distances, such as for office work.

2018: ZEISS SmartLife lenses

ZEISS SmartLife goes beyond a specific, application-oriented approach as a portfolio for single vision, digital and progressive lenses. Based on scientific studies, the lenses are adapted to the visual needs of modern, dynamic and on- the-move lifestyles.