Objective To investigate the distribution of the preferred retinal locus (PRL) of eccentric fixation in eyes with high myopia.Methods A total of 40 highly myopic patients (54 eyes ) with eccentric fixation were examined by MP1 microperimeter to identify the PRL. The position of PRL relative to the fovea was estimated using the 90% confidence ellipse of normal adult foveal fixation. The differences of visual acuity between ldquo;desirablerdquo; and ldquo;undesirablerdquo; PRL were tested by analysis of variance.Results In 54 eyes with high myopia, 24 eyes (44.44%) had PRL of eccentric fixation below the scotoma after loss of central vision; 19 eyes ( 35.19% ) had a leftfield PRL; 6 eyes ( 11.11% ) had an upperfield PRL; and 5 eyes ( 9.26% ) had rightfield PRL. In 14 patients who had binocular eccentric fixation, 13 had the same fixation pattern in both eyes, including lowerfield PRL in 7 （50.00%）, leftfield PRL in 5 （35.71%）, and upperfield PRL in 1 patient （7.14%）. The difference of visual acuity between lower and leftfield PRL group and right and upperfield undesirable PRL group was not statistically significant（F=0.144, Pgt;0.05）. Conclusions The eccentric fixation in eyes with high myopia is usually situated as near as possible to the fovea. The optimal PRL is inferior visual field.
Objective To observe the relationship between position of normal central fixation and the position of the optic disc, and to find out the features of stability of fixation. Methods The position of central fixation of 120 eyes of 60 healthy adults was determined by MP-1 microperimeter. The position of central fixation relative to the position of the optic disk was measured. The relationship between the central fixation and the age or refraction was analyzed statistically. The difference between the right and left eye in each individual was analyzed with t test. Results The central fixation located at the retina with the horizontal distance of 14.48deg;plusmn;1.85deg; and vertical distance of －2.14deg;plusmn;1.26deg; from the temporal edge of the optic disk. In the 120 eyes, 90% of the central fixation located in a bivariate normal ellipse. The normal eyes usually kept in a slightly moving condition when a normal person fixing on a subject. The median of horizontal and vertical deviation was 0.4deg; and 0.3deg; respectively. Conclusion The distribution of central fixation in healthy adults is a bivariate normal ellipse. When fixing on a subject, the moving extent of the eyes in the horizontal direction is larger than that in the vertical direction.
ObjectiveTo identify the clinical significance of epileptic eye movement for localization of posterior epileptic seizures. MethodsThere were 12 posterior epileptic patients, who were undertaken the detailed presurgical evaluation and ictal SEEG recording, and the epileptogenic zone of whom was confirmed restricted within posterior cortex through the boarder of epileptic cortical resection and the result of epileptic surgery, included in the research. ResultsThe cluster analysis of posterior cortical area of interest showed that parieto-occipital sulcus (POS) with the adjacent cortical areas belonged to the Medial Group; intraparietal sulcus (IPS) with the adjacent areas belonged to the Intermediate Group; and the Lateral Group included anterior occipital sulcus (AOS) and posterior temporal cortex. Eyes forced stare had the significant correlation with IPS, POS and related cortical group. Contraversive eye deviation had no significant correlation with cortical eye field with the related cortical areas. ConclusionsForced eye stare was significant eye movement in posterior epilepsy, and had significant correlation with IPS and POS. Ipsiversive eye deviation and convergence binocular movement were rare semiology in posterior epilepsy, and AOS had significant correlation with the two type of epileptic eyes movement.
In current domestic research on laparoscopic training, researchers usually consider instrument movement path in the hand-eye coordination relationship. However, they ignore the information contained in visual cues by which could guide and control instrument movements. Studies in other areas have shown that trainers can improve their perceptual-motor skills by gaze training. This paper was designed to examine the effectiveness of eye gaze tracking technology in laparoscopic training and to analyze gaze strategy of the subjects in different training methods. The Tobii X1 Light Eye Tracker was used to track the gaze position of subjects when they were performing the two-handed transferring task in box trainer, and to obtain parameters related to gaze strategy including the efficiency of task completion, as well as visual search, visual processing and observation transfer analysis based on Markov chain model. The results showed that the completion time during the last training in gaze training group was decreased by 101.5 s comparing to the first training. Compared with video training group, gaze strategy of gaze training group has a significant change, such as fixation and saccade duration rate was increased by 38%, fixation duration on target area was increased, and saccade amplitude increased by 0.58°, and the probability of the fixation point transferring to equipment decreased by 15%. The results demonstrated that eye gaze tracking technology can be used in laparoscopic training, and can improve the subjects’ skills and shorten the learning curve by learning gaze strategies of experts.