Reduced mental effort starts with vision

Cognitive load describes the amount of working memory applied to fulfill a specific task. Working memory is a cognitive system responsible for temporarily holding and processing information needed for complex tasks such as reasoning, learning, and comprehension.

In short, cognitive load is the effort our brain has to make. The term refers to the fact that our brain has a limit to the amount of information it can process at any given time.

Information processing (e.g., recognition of shapes, objects, or the recognition of locations or orientation in space) takes place in different areas of the brain, including the working memory. Visual perception is the process by which the brain interprets and organizes visual information received from the eyes to form a coherent understanding of the environment.

Mental effort refers to the number of cognitive resources expended to perform tasks, process information, or solve problems.

Dr. Annalisa Bosco is Professor of Physiology and Neurophysiology at the University of Bologna. Her research explores how the brain transforms sensory information into action, especially through the link between perception and action. In this video, she states that high-quality lenses that reduce blur may help lower cognitive load by supporting clearer visual input.

Prof. Annalisa Bosco’s recent work shows that eye movements can indicate cognitive states while a person performs a task, offering insight into processes such as cognitive load.

To explain the connection between the brain, the eyes, and mental effort, she highlights extraneous cognitive load as especially relevant to vision. Visual perception is active: the brain processes visual input, assigns meaning, and interprets it in context.

Prof. Annalisa Bosco confirms that when visual input is blurred or degraded, the brain must work harder to reconstruct what is seen, increasing cognitive load. She explains that, in the short term, high cognitive load can cause mental fatigue, concentration difficulties, and errors. Over time, it may contribute to stress with neurobiological effects.

Vision is not only optical – it is neural. When visual input is unclear, the brain must compensate by investing additional working memory resources to interpret what is seen. This is assumed to increase cognitive load and mental effort, especially during visually demanding tasks.

ZEISS ClearMind lenses are engineered to minimize unnecessary visual effort. The integrated ZEISS NeurOptix technology is based on five key principles:

• Mapping real visual behavior:
  ZEISS NeurOptix technology is based on analyses of how people naturally use their eyes throughout the day⁹ i.e. how long eyes stay in certain areas, or how tasks shift between near, intermediate, and distance.
• Pinpointing real visual behavior on the lens surface:
  A sophisticated mathematical model – that integrates ZEISS’ extensive knowledge of ocular movements, visual behavior, and the position of lens wear – facilitates the precise identification of the specific regions on the spectacle lens essential for visual tasks performed in daily life.
• Linking levels of blur perception to cognitive load:
  The ZEISS NeurOptix technology identifies zones where blur creates unnecessary cognitive load. Vision zones where clarity is assumed to create the biggest cognitive benefit are prioritized to ensure the lens supports effortless vision.
• Counteracting cognitive load from lens-induced blur:
  By employing a geometric-optical control algorithm, ZEISS NeurOptix technology offers advanced blur management based on the individual prescription.
• Creating a neural lens fingerprint:
  Using optical, behavioral and neurological insights, ZEISS NeurOptix technology shapes a lens-design fingerprint that mirrors the wearer’s real visual priorities and needs. This means that clarity is provided in the areas most relevant for all-day use, the lens design is optimized for transitions where the eyes naturally move, and lens-geometry-induced blur is minimized in sensitive areas.

Dr. Rajat Agarwala is a Senior Researcher at the Institute for Ophthalmic Research, University of Tübingen, focusing on vision, visual perception, and cognitive science. In the ZEISS Visual Perception Study 2025, he and his colleagues explored how blurry vision affects cognitive load.

The study combined University of Tübingen’s expertise in vision science and optics with University of Bologna’s neuroscience and biomedical technology expertise. Using electroencephalography (EEG), Dr. Rajat Agarwala and his colleagues measured brain activity to understand how blur impacts mental effort, especially in progressive lens wearers

The results showed that blurry or unclear vision increases cognitive load because the brain needs more resources to process visual information. Dr. Rajat Agarwala explains, for eyeglass wearers, clearer zones in progressive lenses may reduce mental effort in everyday tasks such as driving or working. He sees the study as a new research direction, combining visual perception and neuroscience to support future lens design.