Pupilla learning lab
Vision Simulator: Refractive Blur & Visual Acuity
Apply a prescription and watch an eye chart, a page of text and a night street blur the way that refractive error really blurs them, with a live logMAR and Snellen readout.
- Free in your browser
- English & Arabic
- Education & training
Your first practice session
- Choose a scene and inspect the baseline view.
- Apply a prescription and compare the pattern of blur.
- Compare scenes while keeping the prescription fixed.
Common mistakes to avoid
- Interpreting a model acuity readout as a measured patient result.
- Expecting one prescription to describe every person’s visual experience.
For education and training only. Pupilla is not a medical device and must not be used for diagnosis or treatment decisions.
Understand the principles
Refractive errors and astigmatism: myopia, hyperopia and Sturm's conoid
A refractive error means light from a distant object does not focus on the retina when accommodation is relaxed. In myopia the focus falls in front of the retina and is corrected with minus (concave) lenses; in hyperopia it falls behind the retina and is corrected with plus (convex) lenses. In astigmatism the eye has different power in two meridians, so a point of light forms two focal lines separated by the interval of Sturm (Sturm's conoid); a cylindrical lens at the right axis brings both lines together on the retina.
Questions about this simulator
What can I practise with the Vision Simulator: Refractive Blur & Visual Acuity?
Apply a prescription and watch an eye chart, a page of text and a night street blur the way that refractive error really blurs them, with a live logMAR and Snellen readout.
Do I need to install software or create an account?
Open the simulator free in a modern browser without installation. An account enables supported saved progress and results; coverage varies by module.
Can I use a phone or tablet?
You can access it in modern phone and tablet browsers. A larger screen gives diagrams and controls more space; performance depends on the device and browser.
Does this replace clinical training or patient diagnosis?
For education and training only. Pupilla is not a medical device and must not be used for diagnosis or treatment decisions.
References & further learning
Sources for the teaching principles. Listing a source does not imply its institution endorses or validates this simulator.