Teller Acuity Cards®: A Guide to Infant and Nonverbal Vision Testing

Teller Acuity Cards® measure visual acuity in patients who cannot read an eye chart or describe what they see. Rather than asking the patient to identify letters, the examiner watches which way the patient looks. Infants reliably look toward a striped pattern instead of a blank field, so the finest stripe width that still draws the gaze gives an estimate of acuity. The technique is called preferential looking, and it works from birth onward.

Measuring vision in a patient who cannot read a letter chart, or answer a question at all, is one of the oldest problems in clinical vision testing. Teller Acuity Cards® solve it by watching where the patient looks rather than asking what they see.

What Are Teller Acuity Cards®?

Teller Acuity Cards® are a series of standardized testing cards designed to measure visual acuity in patients of any age or ability, and they are especially useful with infants and non-verbal patients.

Each card contains:

• A high-contrast black-and-white grating pattern, in varying sizes, on one side
• A blank grey field background
• A small viewing peephole centered on the card for the examiner
• A reference table on the back with testing distance, cycles per degree (the size of the grating), and estimated Snellen acuity equivalents

Because infants naturally look toward patterns rather than blank spaces, clinicians can determine whether the patient detects the grating by observing their eye movements. This testing method is known as preferential looking.

As the examination progresses, the stripe widths become progressively finer until the infant can no longer distinguish the pattern, which gives an estimate of visual acuity.

The graded card series. Stripe widths become progressively finer across the set, and the point at which the patient stops responding gives the acuity estimate.

Teller Acuity Cards® were developed by Dr. Davida Y. Teller and a research team in the Department of Psychology at the University of Washington. Follow-up development and testing were conducted by Dr. Velma Dobson, Dr. D. Luisa Mayer, and other researchers. Teller Acuity Cards® is a registered trademark of the University of Washington and is manufactured by Precision Vision under license.

What Is Preferential Looking?

Preferential looking is a well-established behavioral testing method used to estimate vision in patients who cannot respond verbally.

Instead of asking the patient to identify letters or symbols, the examiner observes where the patient naturally looks. If the infant consistently looks toward the striped pattern instead of the blank background, it indicates they can resolve that level of spatial detail.

The card is held at a fixed distance while the examiner observes from behind it, judging which side the infant looks toward.

This objective behavioral response allows clinicians to determine infant visual acuity without requiring verbal communication or subjective responses.

Who Should Be Tested with Teller Acuity Cards®?

Teller Acuity Cards can be used on any patient, but they are the best solution for:

• Infants from birth through early childhood
• Premature infants
• Children with developmental delays
• Patients with neurological impairments
• Non-verbal children and adults
• Patients with disabilities
• Patients where a language barrier exists between the patient and clinician
• Emergency room patients suspected of having a traumatic brain injury (TBI)
• School screening programs

They are also widely used in clinical research where standardized pediatric visual acuity measurements are required.

No verbal response is required, which is what makes the method workable from birth onward.

Why Early Infant Vision Testing Matters

Vision develops rapidly during the first years of life. Conditions that go undetected during this critical period may result in permanent vision loss or delayed visual development.

Early vision assessment can help identify:

• Amblyopia (lazy eye)
• Cataracts
• Retinal disorders
• Optic nerve abnormalities
• Cortical visual impairment
• Neurological conditions affecting vision
• Developmental vision delays

Early diagnosis allows providers to begin treatment during the period when the visual system is most responsive.

Advantages of Teller Acuity Cards®

Standardized testing

Teller Acuity Cards provide consistent, repeatable testing procedures that help reduce variability between examiners and testing locations.

Scientifically validated

The preferential looking method has been extensively studied and is recognized throughout pediatric ophthalmology and vision research. You can read more about how our tests are validated on our Scientific Validation in Vision Testing page.

Non-invasive

Testing is comfortable and requires no verbal communication, making it ideal for infants and patients with communication challenges.

Reliable results

Teller Acuity Cards provide reproducible measurements that support both clinical decision-making and longitudinal patient monitoring.

Clinical Applications

Teller Acuity Cards are used in a wide variety of healthcare settings, including:

• Pediatric ophthalmology practices
• Optometry clinics
• Children's hospitals
• Vision rehabilitation centers
• Low vision centers
• University research programs
• Early intervention programs
• Neonatal follow-up clinics
• Clinical trials evaluating vision outcomes
• Non-profit organization and charity missions

Best Practices for Infant Vision Testing

To achieve consistent results, clinicians should:

• Test in a quiet, distraction-free environment
• Maintain the recommended testing distance
• Ensure appropriate room lighting
• Observe natural eye and head movements carefully
• Progress through the card sequence methodically
• Document results consistently for future comparison

Following standardized testing procedures improves reliability and supports better clinical decision-making.

Discover Precision Vision Teller Acuity Cards®

Early vision assessment plays a critical role in supporting healthy visual development. Precision Vision's Teller Acuity Cards provide clinicians and researchers with a trusted, standardized solution for evaluating infant visual acuity using proven preferential looking techniques.

Ready to learn more? Explore our Teller Acuity Cards®, or browse the heavy duty storage box and individual replacement cards.