ABSTRACT
This chapter discusses the aim and the background for the measurement of the level of resolution of a visual system. It provides lists of equipment required for this measurement in infants (pre-verbal; 0–6 months old), verbal children (3–4 years old) and illiterate adults, and literate children (>4 years old). The chapter presents the instructions on the techniques of clinical examinations and methods of undertaking practical procedures. A bullet-pointed, step-by-step walk-through of the key steps for the skill, with pearls, are also presented. Illiterate adults and children require special acuity-measurement strategies, which must be tailored to the subject’s age and literacy. The eye not being tested should be occluded. This can be done with an amblyopia occlusion patch. In these cases, binocular acuity should then be measured.
