The author constructed an apparatus for measuring the visual acuity objectively by evoking optokinetic nystagmus. The stimulus for eliciting the nystagmus is vertically drawn lines on a white paper, which is driven horizontally by a motor. The width of lines ranged from 1.Omm to 15mm, the distance of each line being the same as the width of lines. The occurrence of nystagmus was verified by observing with corneal microscope and slit lamp. At a distance of 5m, with few exceptions, the finest lines which elicited nystagmus was determined. In the subjective determination of visual acuity, Landolt ring was used. With this equipment and procedure, 156 persons, 312 eyes were examined. A comparison has been made between the gap width of the Landolt ring and the width of line. The results are compiled into able. A statistical treatment shows a highly significant correlation (coefficient, O.96) for the relation between the gap width of the ring and line width which elicited nystagmus. The mutual relationship of these two values is expressed as regression equation. From this results, it is concluded that this procedure is suitable for the objective determination of visual acuity. The author also tried to establish whether the arresting of optokinetic nystagmus is suitable for the objective visual acuity measurement. This method, however, failed to show any reliability. The various methods previously used for the objective measurement of visual acuity are reviewed.
Humans ; Nystagmus, Optokinetic* ; Visual Acuity*

PURPOSE: The purpose of this paper was to determine the correlation between optokinetic nytagmus and grating and Snellen visual acuity charts and the validity of this correlation as an index. METHODS: Diffusion blur was used to cause visual decrease in 24 patients with normal eyes. Vision was measured using 3 different methods. To compare the central and peripheral vision, visiual acuity was measured using a macula occluder. RESULTS: Twenty four patients had an average uncorrected vision of 1.0 and showed regular visual acuity decrease using diffusion blur. Grating visual acuity showed correlation with the Snellen visual acuity but OKN visual acuity showed low correlation (p<0.05, ANOVA with repeated measure trend). OKN visual acuity showed low correlation with grating acuity when central visual acuity was occluded and only peripheral acuity was taken into consideration. CONCLUSIONS: Visual acuity measured using Snellen or grating acuity had little correlation with OKN visual acuity, and visual acuity measured using OKN was unable to indicate visual acuity in a quantitative manner.
Diffusion ; Humans ; Nystagmus, Optokinetic* ; Visual Acuity*

Normally, the fast phase of optokinetic nystagmus (OKN) beats on the opposite direction to the movement of an optokinetic stimulus. The fast component of OKN beating in the same direction are called "reversed OKN". Eventhough the mechanism of reversed OKN is still disputed, it is well known that reversed OKN occurs exclusively in patients with congenital nystagmus, or in some cases, with acquired neurologic disease. It is easy to diagnose the congenital nystagmus when the spontaneous nystagmus can be seen at birth. But when the congenital nystagmus can be seen only on eccentric gaze or when the patient has a wide neutral region around the primary position, the abnormal eye movement can not be detected until a medical examination is performed. It is thought that causes of reversed OKN may be the abnormal neural decussation of the visual system or spontaneous nystagmus. Recently, we experienced two cases of bidirectional reversed OKN as a congenital nystagmus. One patient had bilateral reversed optokinetic nystagmus and gaze evoked nystagmus, whereas the other patient had periodic alternative nystagmus and bilateral reversed OKN. Bilateral reversed OKN may be one of the pathognomic signs of congenital nystagmus.
Eye Movements ; Humans ; Nystagmus, Congenital ; Nystagmus, Optokinetic* ; Parturition

The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects and subjects who need legal judgements. To produce more reliable objective method, we made a new objective system for visual acuity test which is called Seohan visual acuity test(SVT). The SVT system has three elements such as stimuli, display and evaluation. For the visual stimuli, the computer program for optokinetic nystagmus(OKN)test was set up in personal computer to control the size, speed and direction of the stimuli easily. The visual stimuli are presented on HeadMounted-Display(HMD)to separate the stimuli from the environment to keep the uniform size and distance of screen to the eye of subjects and project the stimulus in full central field of patient. Electrooculography(EOG) was used to assess the visual acuity more objectively. To evaluate the usefulness of SVT, the smallest size of the stimulus to elicit OKN(objective visual acuity)with SVT was obtained in 10 eyes in each twelve grade of subjective visual acuity(decimal V). Objective visual acuity(VA)were distributed from 8.3+/-1.87 to 21.4+/-3.1 and showed high correlation(p<0.00 ). The relationship between the objective VA obtained from SVT and subjective VA make a regression line(y=-12.874X+21.303).Subjective VA could be obtained from conversion of objective VA with 95%confidence belt. In conclusion, the objective visual acuity with SVT is highly correlated with subjective visual acuity and SVT using the OKN response to stimuli presented on HMD by the computer program can be useful in assessing visual function objectively.
Electrooculography ; Humans ; Infant ; Microcomputers ; Nystagmus, Optokinetic* ; Visual Acuity*

The study wasdesigned for the evaluation of diagnostic usefulness of standard electro-oculography (EOG) battery in differentiating the vertigo of central origin from that of peripheral one. Twelve patients of definite posterior fossa lesion proved by MRI or CT scan were selected as a central group and fourteen patients of peripheral vestibulopathy as a peripheral group. Using our laboratory standard methods of EOG battery, age-matched normal valuse of bithermal caloric responses(fixation supperssion, vestibular paresis, and directional preponderance) and the gains of pursuit and optokinetic nystagmus were obtained. Abnormal vestibular paresis was found in 21 patients of the peripheral group, but in only one patient of the central. Directional preponderance did not show significant difference between the peripheral and central group (p<0.01). In peripheral group, the fixation suppression index (percent change in slow-phase velocity with visual fixation during the period of maximum intensity of caloric nystagmus) was 56.8+8.3%, p>0.01). However, failure of fixation suppression was noted in eleven patients of central group and its mean value of 92.6+7.3%, which was significant statistical difference compared with peripheral and control group (p<0.01 respectively). Defective suppression of caloric nystagmus was more remarkable when the direction of caloric nystagmus was induced toward the lesion site. Such findings were demonstrated in six patients of eight patients with definits unilateral cerebellar hemispheric lesions. In addition, the gains of pursuit and optokinetic nystagmus were significantly reduced in the patients showing defctive fixation suppression compared with whom showed normal pattern of fixation suppression (p<0.01). Therefore, fixation suppression, vestibular paresis, and the gains of pursuit and optokinetic nystagmus would be useful diagnostic paremeters in differntiaging the vertigo of central origin from that of the peripheral.
Electrooculography ; Humans ; Magnetic Resonance Imaging ; Nystagmus, Optokinetic ; Nystagmus, Physiologic ; Paresis ; Tomography, X-Ray Computed ; Vertigo*

BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.
Eye Movements ; Head ; Heredity ; Humans ; Nystagmus, Congenital* ; Nystagmus, Optokinetic ; Phenotype ; Pursuit, Smooth ; Reflex, Vestibulo-Ocular ; Saccades ; Strabismus ; Vision Disorders

BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.
Eye Movements ; Head ; Heredity ; Humans ; Nystagmus, Congenital* ; Nystagmus, Optokinetic ; Phenotype ; Pursuit, Smooth ; Reflex, Vestibulo-Ocular ; Saccades ; Strabismus ; Vision Disorders

Optokinetic nystagmus(OKN) is commonly employed in the assessment of central vestibular lesion. Asymmetry in the OKN has been found in lesions ipsilateral to the direction of the slow phase in parietal lobe, in brain stem, and in the cerebellum. Asymmetry of the OKN may also occur in peripheral vestibular lesions due to spontaneous nystagmus, and this may explain why even enhanced velocities of OKN are sometimes met in these patients. The ocular abnormality as congenital strabismus, extraocular paresis, and congenital nystagmus can cause abnormalities of optokinetic nystagmus. We investigated the clinical significance of OKN test and spontaneous nystagmus for differentiation of peripheral and central vestibular disorder. In this study, we recorded the optokinetic nystagmus by the electronystagmography. We divided the optokinetic response from normal to type III according to direction of the nystagmus and difference of(Rt-Lt) Vmean. At the result, all of the vestibuloneuronitis who had the optokinetic abnormality showed type I OKN abnormality with spontaneous nystagmus. Type II and type III OKN abnormality always appeared in central vertigo patients. Type I OKN abnormality could be seen in peripheral and central vertigo patient. But half of the central vertigo patients who had type I OKN abnormality did not have spontaneous nystagmus. We could not correlated OKN abnormality with specific location of central nervous system.
Brain Stem ; Central Nervous System ; Cerebellum ; Electronystagmography ; Humans ; Nystagmus, Congenital ; Nystagmus, Optokinetic* ; Paresis ; Parietal Lobe ; Strabismus ; Vertigo

It is well known that optokinetic responses are disturbed in the parietal lobe lesion. Also such a lesion manifests visual field defect. Authors predicted a superficial brain lesion sparing optic radiation in the parietal lobe, which might interfere optokinetic nystagmus. As a control group, one hundred healthy adults were examined and all of them showed normal symmetric optokinetic responses. In the study group, ten cases of cerebral paragonimiasis with their cystic formation in the posterior parieto-occipital area involving mostly Brodmann's are 18 and 19, seven cases of various brain tumors and eight cases of craniocerebral injury were observed for optokinetic nystagmus with correlation to visual field.
Adult ; Brain ; Brain Neoplasms ; Craniocerebral Trauma ; Humans ; Nystagmus, Optokinetic* ; Paragonimiasis ; Parietal Lobe ; Visual Fields

Transient cortical blindness is a known but rare complication occurring in 0.3~1% of patients undergoing cerebral or vertebral angiography. It is an extremely rare complication following cardiac catheterizaton and coronary arteriography. Cortical blindness is characterized by complete loss of visual perception and optokinetic nystagmus with preservation of ocular motility, pupillary responses, and normal fundoscopic examination. It has been suggested that its occurrence is due to an adverse reaction to the contrast agent, which causes an osmotic disruption of the blood-brain barrier. Patients outcome appears to be generally favorable with return of vision within 24-48 hr. We report a case of 48 year-old male patient with transient bilateral cortical blindness after coronary angiography.
Angiography ; Blindness, Cortical* ; Blood-Brain Barrier ; Coronary Angiography* ; Humans ; Male ; Middle Aged ; Nystagmus, Optokinetic ; Visual Perception