Ophthalmologists calculate the astigmatism grade with different methods. One of them is a test called retinoscopy, which consists of projecting a beam of light that moves vertically and horizontally into the eye. The examiner observes the movement of the retina reflex and places lenses in front of the eye until the movement of the reflex is neutralized.
Currently, this process is no longer carried out manually but is carried out through the use of devices that perform the measurement automatically, which translates into a much more specific and accurate diagnosis since the part subjective characteristic of traditional manual tests.