[Evaluation of the usefulness of methods of diagnosing eyestrain]

The examinations have been carried out under model conditions in women aged 33.6 +/- 3.8, in whom refraction defects or other sight organ disorders had been excluded. In order to select factors that would be most sensitive and specific for evaluation of visual fatigue, variations in the following indices of the sight organ occupational condition have been analysed: the near vision point, dispersing lens tolerance, retina sensibility, critical fusion frequency, speed and accuracy of perception, visual simple and choice reaction time. The indices have been analysed under the performance of sigh work and medium-hard physical effort. Variations in the near point and retina irritability have been regarded the most sensitive and specific indices of asthenopia. In addition, intra- and interpersonal variability, as well as seasonal variability of the indices listed have been assessed. Significant seasonal differences have been found between the values measured in the persons prior to work in summer and winter for near vision sense point, dispersing lens tolerance, retina irritability, and critical fusion frequency.