A reexamination of end-point and rebound nystagmus in normals.

In order to detail the characteristics of end-point (EPN) and rebound nystagmus (RN), two series of experiments were performed with infrared oculography for measurement of horizontal eye movements. Experiment 1 consisted of EPN recordings during sustained lateral gaze (40° and 50°) in 20 normal subjects. Experiment 2 consisted of recordings of RN in 5 normal subjects. Nine of 20 subjects demonstrated a jerk EPN. EPN almost always appeared immediately and was sustained for 15-25 sec. In Experiment 2, RN occurred in 5 of the 5 subjects who demonstrated EPN. The mean amplitude of RN was always less than that of EPN, and decayed over a 5-10-sec time period. The experiment demonstrated that RN can be evoked in normals even when a fixation target, in a fully lit room, is present

The pupil in dominant optic atrophy

purpose. To compare visual and pupil afferent function in dominant optic atrophy (DOA). methods. Patients with DOA who belonged to families showing evidence of linkage to the locus on chromosome 3q28-qter were recruited from the Moorfields Genetic Register. Patients and healthy control subjects underwent visual and pupil perimetry using a modified automated perimeter (Octopus 1-2-3; Interzeag, Schlieren, Switzerland). Five stimulus locations were tested: fixation, and at 17° eccentricity along the 45° and 135° meridians in all four quadrants. The visual deficit (difference in decibels between the patient’s luminance threshold and that in age-matched healthy control subjects) was compared directly with the pupil deficit (difference in decibels between the stimulus intensity giving the patient’s pupil response and that giving an equivalent pupil response in healthy control subjects) at each test location. results. Visual deficits and pupil afferent deficits were found at all five locations. The visual deficits were significantly greater than the pupil deficits at the four peripheral locations (median difference = 6.3 dB, P < 0.001). At fixation, the difference was not significant (median difference = 2.3 dB, P = 0.407). conclusions. Pupil function appears less affected than visual function at four of five locations tested. This result provides evidence that the retinotectal fibers serving the pupil light reflex are less susceptible to damage from the OPA1 genetic defect than the retinogeniculate fibers serving vision

The presumed influence of attention on accuracy in the developmental eye movement (DEM) test

BACKGROUND: The developmental eye movement (DEM) test is a clinical test used widely to evaluate ocular motility function (accuracy and speed) in school-age children. PURPOSE: The purpose of this study was to investigate, retrospectively, the change in accuracy over time while performing the DEM horizontal reading task in children. METHODS: The charts from children who had performed the DEM test during a routine eye examination in a pediatric optometry service were reviewed. The study included 22 patients (6 to 11 years old, 12 boys, 10 girls) who had a routine eye examination that was precepted by one of the authors (R.C.) during the period of 1995 to 1999. Patients were divided into two categories: 1) those with abnormal DEM test results and 2) a control group consisting of those with normal DEM test results. Chart review was done consecutively within each category. Collected data included patient age, gender, refractive error, and DEM test results. For analysis, the horizontal task of the DEM was divided into two halves (I and II), Part I always preceded part II, and data was sorted as the number of errors per part. RESULTS: More errors in accuracy occurred in part II than in part I (Wilcoxon signed rank test, p \u3c or = 0.01) of the horizontal DEM test in the group of subjects with an abnormal DEM test. No differences in the number of errors in parts I and II of the horizontal task of the DEM were found in the control group. CONCLUSIONS: Findings showed that when excessive errors in accuracy occurred, the number of errors increased over time. If the errors were caused by an oculomotor dysfunction found in the DEM, errors should be equally distributed throughout the text. If errors were caused by fatigue, a difference in parts I and II should have occurred in both the test and the control group. These findings suggest that attention may influence accuracy over time in those patients that do poorly on the DEM test