[Comparative evaluation of healthy preschool children blink].

PURPOSE To evaluate spontaneous blink activity in the primary eye position in normal preschool children. METHODS Two hundred normal children aged 4 to 6 years were prospectively evaluated. They were digitally videotaped in a standard setting, taking the images on frontal and lateral plans, during the vigil state, in the primary eye position. The object of observation was located at the same level of the pupil. A Sony Lithium camera was used. The images were recorded on 8 mm tapes and transferred to a personal computer (MacIntosh G4) and processed with the iMovie software. Opening, closure and total blink times were measured using frame scale. The eyelid movement rhythm per minute was also evaluated, during three minutes. The data were submitted to statistical analysis. RESULTS The complete eye blink was more frequently observed than the incomplete eye blink. The blink rate increased with age. The incomplete blink rate was the same for all the evaluated ages. The eyelid opening and closing times and the complete blink time were similar for both sexes, during all evaluation moments. There were no differences between genders regarding eye blink. The closing eyelid time was slower than the opening eyelid time. CONCLUSIONS The complete blink rate increases with age. The closing and the opening eyelid times and the complete blink were similar for both sexes in all evaluated ages and the opening time is faster than the closing time.