What is the most common way to record visual acuity in infants and pre-verbal children?

The most common method to record visual acuity in infants and pre-verbal children is the preferential looking method, often referred to as the Chester Screen Method (CSM). This technique effectively assesses visual acuity by evaluating the infant's ability to discriminate between visual patterns or stimuli, often using a series of cards with varying levels of contrast and complexity.

In this method, the infant is presented with two different visual stimuli, and their gaze direction is observed. If the child consistently looks at one pattern over another, it suggests a preference for the more complex or clearer image, indicating better visual acuity. This is crucial for assessing visual function in very young patients who cannot verbalize or actively respond to questions or traditional testing methods.

Other methods may have their applications; for instance, the Marty Contrast Sensitivity (MCS), although useful, does not specifically address visual acuity measurement. Thus, the Chester Screen Method stands out as the standard approach for the age group, emphasizing the importance of adapting visual assessments to the developmental level of the patient.