Optonet Vision Unit Documentation
Please note that this User Guide is being currently updated; new sections will be added shortly.
The recommended VA optotype is composed of “Sloan” letters. In addition to Sloan letters, we can choose from a variety of other optotypes, which are also scaled according to log units. Alternatives include the British letters, Numbers, Landolt’s “Cs”, Snellen’s “Es”, or Symmetric Letters. These latter optotypes allow the measurement of VA, as well as subjective refraction, in patients who need simplified testing methods due to young age, low vision, or cognitive impairments. Below is a more detailed description of these optotypes.