[Studies on ocular positions at close distance with a new system of measuring ocular positions]

The purpose of our study was to develop a new system of measuring ocular positions and to assess its clinical applicability. This system is derived from that of the Hess coordimeter and is used at a distance of 40 cm. Our system enables us to distinguish tropia from phoria by testing the ocular positions both with and without a fusional target which can be seen by both eyes. All devices are installed in one structure and it can be used in a lighted room. The system was checked in 10 normal subjects by plotting the data of the charts onto a graph and deriving a static eye position curve. There was no significant vertical deviation, and there was an exodeviation of 5.32 +/- 3.78 (mean +/- standard deviation) degrees without a fusional target, but no significant deviation occurred when the fusional target was lighted. In 37 of the 38 patients with ocular motor disturbance, the results with this system corresponded well with those obtained by the Hess coordimeter or prism cover test. One particular case with extraocular myositis involving more than two extraocular muscles showed an atypical complicated pattern. We believe that our system is simple and easy for clinical evaluation of ocular movement abnormality in ophthalmic diagnosis.