Original papers: A ladder of Ryser filters in the diagnosis of strabismus

The authors report a preliminary study on the usefulness of Ryser filters fixed on a pole to evaluate the degree of penalization needed to induce the imbalance of visual inputs coming through the right and the left eye. The method was tested on 87 patients, suffering from pure DVD (22 cases), esotropia associated with dvd (54 cases) and esotropia associated with dvd and dtd (II cases). The ladder, built of stratified polycarbonate, contains eight filters according to the scale 0-1.0-0.8-0.6-0.4-0.3-0.2-0.1-<0.1, and, despite the high penalizing capacity of the last filters, allows a good observation of the examined eye through the pole.