Pediatric visual acuity examinations and vision care

The visual system of newborn infants is not like that of adults. Both ocular and neural structures essential for vision will undergo anatomical and physiological changes as maturation process. The maturation of all visual systems occurs relatively rapidly in normal children. So, early examination of visual acuity is critical for normal visual funciton achievement. Visual acuity in preverbal children can be assessed using several techniques, such as fixation and following behavior under both monocular and binocular conditions, the optokinetic nystagmus technique, preferential looking, visual evoked potential, and recognition acuity using a vision chart. Most clinicians consider the standard technique of recognition acuity to be the gold standard for visual acuity assessments, 20/20 vision should be achieved by 7 years of age. Significant refractive error, a high degree of hyperopia, myopia, or astigmatism may result in not only blurred vision, but also strabismus and amblyopia. Therefore, early vision screening is very valuable. Subjective and objective refractive techniques are standard for detecting significant refractive errors in children and are available under either non-cycloplegic or cycloplegic conditions. Amblyopia is the most common cause of vision loss in children and young adults, defining as a reduction of best-corrected visual acuity due to the interruption of normal visual development during the so-called sensitive period. If the problem is not identified until the sensitive period is complete, the vision loss is permanent. Visual impairment in childhood affects all aspects of the child's development. Earlier treatment is associated with better outcomes. Of course, patient compliance and parental support are the most important factors contributing to treatment success.

Pediatric visual acuity examinations and vision care

The visual system of newborn infants is not like that of adults. Both ocular and neural structures essential for vision will undergo anatomical and physiological changes as maturation process. The maturation of all visual systems occurs relatively rapidly in normal children. So, early examination of visual acuity is critical for normal visual funciton achievement. Visual acuity in preverbal children can be assessed using several techniques, such as fixation and following behavior under both monocular and binocular conditions, the optokinetic nystagmus technique, preferential looking, visual evoked potential, and recognition acuity using a vision chart. Most clinicians consider the standard technique of recognition acuity to be the gold standard for visual acuity assessments, 20/20 vision should be achieved by 7 years of age. Significant refractive error, a high degree of hyperopia, myopia, or astigmatism may result in not only blurred vision, but also strabismus and amblyopia. Therefore, early vision screening is very valuable. Subjective and objective refractive techniques are standard for detecting significant refractive errors in children and are available under either non-cycloplegic or cycloplegic conditions. Amblyopia is the most common cause of vision loss in children and young adults, defining as a reduction of best-corrected visual acuity due to the interruption of normal visual development during the so-called sensitive period. If the problem is not identified until the sensitive period is complete, the vision loss is permanent. Visual impairment in childhood affects all aspects of the child's development. Earlier treatment is associated with better outcomes. Of course, patient compliance and parental support are the most important factors contributing to treatment success.

Clinical significance of saccade test, smooth pursuit test, and optokinetic nystagmus test in nystagmography / 영남의대학술지

BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo.METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo.RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo.CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.

Clinical significance of saccade test, smooth pursuit test, and optokinetic nystagmus test in nystagmography / 영남의대학술지

BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo. METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo. RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo. CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.

Avaliação oculomotora em adultos: um estudo do efeito da idade e de alterações visuais / Oculomotor evaluation in adults: a study of the effect of age and visual alterations

RESUMO Objetivo Avaliar os movimentos oculares de sácadas, perseguição e o nistagmo optocinético em adultos, analisando o efeito da idade e das alterações visuais. Métodos Foram avaliados 40 sujeitos de ambos os gêneros, com faixa etária de 20 a 49 anos de idade, sem queixas auditivas ou vestibulares e que apresentaram avaliação audiológica básica dentro dos padrões da normalidade e ausência de nistagmo espontâneo de olhos abertos, nistagmo semi-espontâneo e nistagmo espontâneo de olhos fechados maior que 6º/s. Todos os participantes foram submetidos às provas de nistagmo espontâneo, nistagmo optocinético, movimentos sacádicos fixos, aleatórios e rastreio pendular, por meio da vectoeletronistagmografia computadorizada. Os achados foram analisados segundo as variáveis idade e presença de alteração visual, do tipo ametropias. Os resultados passaram por análise estatística descritiva e inferencial. Resultados Não houve diferença nas provas de nistagmo optocinético, sacádico fixo, aleatório e rastreio pendular, quando analisadas com relação à idade. Quanto à variável alteração visual, a preponderância direcional do nistagmo, observada na prova do nistagmo optocinético, foi maior em indivíduos com alterações visuais. Nos movimentos sacádicos aleatórios, também se observou diferença em relação à velocidade máxima, sendo maior em indivíduos sem alterações visuais. Conclusão As provas oculomotoras não sofreram influência do fator idade na faixa etária pesquisada, porém, a presença de alterações visuais exerceu influência em alguns dos parâmetros das provas oculomotoras.

ABSTRACT Purpose To evaluate saccadic and pursuit ocular movements and optokinetic nystagmus in adults, analyzing the effect of age and visual alterations. Methods We evaluated 40 subjects of both genders, aged 20-49 years, with no auditory or vestibular complaints and who presented a normal basic audiology evaluation, absence of spontaneous nystagmus with open eyes, semi-spontaneous nystagmus, and spontaneous nystagmus with eyes closed greater than 6º/s. All participants underwent the tests of spontaneous nystagmus, optokinetic nystagmus, fixed and random saccadic movements, and pendular tracking using computerized vectoelectronystagmography. The findings were analyzed according to age and visual changes (ametropias). The results underwent a descriptive and inferential analysis. Results There was no difference in the tests of optokinetic nystagmus, fixed and random saccadic movement, and pendular tracking when analyzed with regard to age. As for the variable presence of visual alteration, directional preponderance of nystagmus, observed in the optokinetic nystagmus test, was higher in individuals with visual alterations. In the random saccadic movement, there was also a difference in relation to the maximum velocity, which was higher in individuals with no visual alterations. Conclusion The oculomotor tests were not affected by the age factor in the studied age group, but the presence of visual alterations exerted influence on some of the parameters of the oculomotor tests.

Eye Movement Abnormalities and Neuroimaging Findings of Disequilibrium of Unknown Origin / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Although disequilibrium is common type of dizziness in older people, it is sometimes difficult to identify a specific cause for this problem. The diffuse brain pathology including subcortical ischemia and atrophy can be a cause for patients with disequilibrium of unknown cause. Aim of this study is to identify the eye movements and neuroimaging features in patients with disequilibrium. MATERIALS AND METHODS: We performed a prospective investigation in patients with disequilibrium of unknown cause. We collected information on demographic characteristics and clinical features of disequilibrium. The impact of dizziness on everyday life was assessed by 25-item dizziness handicap inventory (DHI). Vestibular function test (VFT) includes smooth pursuit, saccade, optokinetic nystagmus, and rotatory chair test. Subcortical white matter lesions and brain atrophy were graded from brain magnetic resonance image (MRI). RESULTS: This study included 14 patients (12 female and 2 male), aged between 64 and 84 years, mean age 74.01+/-6.02 years. The score of DHI was 39.4+/-11.8 (20-58). Eye movements were abnormal in 13 patients and normal in only one patient. The degree of subcortical ischemia was mild in 7, moderate in 4, and severe in 3 patients. Ventricular brain ratio was 0.23+/-0.03. However, there was no significant relationship between MRI findings and the degree of oculomotor alterations (result of VFT). CONCLUSION: Patients with disequilibrium of unknown cause are usually elderly women. Alterations in oculomotor movements and diffuse brain pathology including white matter lesions and atrophy were observed in patients with disequilibrium of unknown cause.

Oculomotricity parameters in digital nystagmography among children with and without learning disorders / Parâmetros de oculomotricidade à nistagmografia digital em crianças com e sem distúrbios de aprendizagem

The saccadic pathway involves numerous regions of the brain cortex, the cerebellum and the brainstem. Saccadic movement latency, velocity and precision parameters assess the efficacy of central nervous system (CNS) control over rapid eye movements. Very few disorders which alter the CNS are missed when these parameters are carefully measured using a computer. Pendular tracking assesses the integrity of the oculomotor system in controlling slow eye movements - vulnerable to CNS and vestibular system dysfunctions. Optokinetic nystagmus represents a stereoceptive response which compensates environment movements by psycho-optical inputs. AIMS: to compare the oculomotricity values found in children with and without learning complaints. MATERIALS AND METHODS: prospective study. We included in the study 28 children of both genders, within the age range between 8 and 12 years, with learning disorders (study group) and 15 without (control group). We carried out the fixed and randomized saccadic movement tests, pendular tracking study and optokinetic nystagmus. RESULTS: There was a statistically significant difference between the groups concerning the randomized saccadic movement velocity parameters and in the pendular tracking test. CONCLUSION: The children with learning disorders presented alterations in some oculomotricity tests when compared to children without complaints.

A via sacádica envolve várias regiões do córtex cerebral, cerebelo e tronco encefálico. Os parâmetros latência, velocidade e precisão dos movimentos sacádicos avaliam a eficiência do controle do sistema nervoso central (SNC) sobre os movimentos rápidos dos olhos. Poucas desordens que alteram o SNC deixam de ser detectadas quando esses parâmetros são medidos com rigor por meio de um computador. O rastreio pendular avalia a integridade do sistema oculomotor no controle dos movimentos oculares lentos, vulneráveis a disfunções do SNC e do sistema vestibular. O nistagmo optocinético representa uma resposta exteroceptiva que compensa os movimentos do meio ambiente por impulsos psico-ópticos. OBJETIVO: Comparar os valores da oculomotricidade encontrados em crianças com e sem queixas de aprendizagem. MATERIAL E MÉTODO: Estudo prospectivo. Foram incluídas no estudo 28 crianças, de ambos os gêneros, faixa etária de 8 a 12, anos com distúrbios de aprendizagem (grupo estudo) e 15 sem (grupo controle). Foram realizados os testes de movimentos sacádicos fixos e randomizados, pesquisa do rastreio pendular e nistagmo optocinético. RESULTADOS: Houve diferença estatisticamente significante entre os grupos nos parâmetros de velocidade dos movimentos sacádicos randomizados e na pesquisa do rastreio pendular. CONCLUSÃO: As crianças com distúrbios de aprendizagem apresentaram alterações em algumas provas de oculomotricidade quando comparadas com crianças sem queixas.

Usefulness of Computerized Objective Visual Acuity Test System Using Suppression Method

PURPOSE: The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects, and subjects who need legal assistance. We designed an objective system for visual acuity test (SOVAT) consisting of three components: stimuli applied via a suppression method, display and evaluation and made a suppression method as stimuli component for SOVAT. Usefulness of the SOVAT was evaluated. METHODS: The visual stimuli were presented on a high-resolution head-mounted display (HMD). An eye movement tracking program and gaze monitoring device allowed us to monitor the patient's fixation status during the test. The suppression method, in addition to a conventional induction method, was developed to use with the SOVAT and its accuracy and confidence level were evaluated. RESULTS: On the basis of clinical data, we present the reference values for the SOVAT as below. For the induction method, objective visual acuity (smallest pixel size), the presumed subjective visual acuity was 3: 0.35-0.6, 7: 0.05-0.25, 12: below 0.05 and for the suppression method it was 1: 0.6-1.0, 1.5: 0.4-0.7, 3: 0.15-0.4, 5: 0.1-0.2. CONCLUSIONS: SOVAT using this suppression method to assess objective visual acuity proved to be more useful than that with a conventional induction method, especially in the range of high visual acuity.

Value of visual nystagmography in diagnosis of the patients with vertebrobasilar transient ischemic vertigo / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the changes of visual nystagmography(VNG) in patients with vertebrobasilar transient ischemic vertigo(VBTIV), explore their clinical value in diagnosis of the patients with VBTIV.@*METHOD@#Thirty-eight patients who complained vertigo and imbalance with VBTIV were selected as experimental group for testing of visual nystagmography (VNG). Twenty normal persons were chosen as control group. The result was analyzed.@*RESULT@#In the experimental group, there was one case that had spontaneous nystagmus and 29 cases (76.3%) with positional nystagmus. The positional nystagmus intension in those patients was (4.08+/-3.18) degrees/s, which was much higher as compared with the control group( P <0.01). The incidence was 39.5% for positioning test. One or more abnormal findings for visual-oculomotor system examination were shown in 28 patients (73.7%). These abnormal findings included saccade test in 26 cases (68.4%), eye tracking test type III in 13 cases and type IV in 3 cases in all 16 cases (42.1%), optokinetic nystagmus in 17 cases (44.7%). There was none with gaze nystagmus. Caloric test showed canal paresis in 19 cases (50.0%) and directional preponderance in 6 cases (15.9%). In Amount distributing of the general slow phase velocity there is a difference between test group and control group.@*CONCLUSION@#Not only vestibular centrum but also peripheral system was involved in patients with VBTIV. These results suggest that VNG be used as important diagnostic test for patients with VBTIV and might be helpful for the location diagnosis of VBTIV.

Clinical and Oculographic Findings of X-linked Congenital Nystagmus in Three Korean Families

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.

Clinical and Oculographic Findings of X-linked Congenital Nystagmus in Three Korean Families

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.

Avaliação oculomotora em pacientes com disfunção vestibular periférica / Oculomotor evaluation in patients with peripheral vestibular dysfunction

OBJETIVO: Verificar se os parâmetros dos movimentos sacádicos fixos e randomizados, do rastreio pendular e do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica. MÉTODO: Foram avaliados 60 pacientes, de ambos os sexos, com tontura de origem vestibular periférica e idade entre 12 e 82 anos. Os achados foram comparados com um padrão de normalidade para os parâmetros dos movimentos oculares estudados. RESULTADOS: Os movimentos sacádicos fixos estavam alterados em 100 por cento dos casos quanto à latência e em 35 por cento quanto à velocidade; os randomizados estavam alterados em 100 por cento quanto à latência, em 78,3 por cento quanto à precisão e 1,7 por cento quanto à velocidade; o rastreio pendular apresentou alteração do ganho nas freqüências de 0,1Hz em 15 por cento, 0,2Hz em 21,7 por cento e 0,4Hz em 13,3 por cento; o nistagmo optocinético apresentou alteração da velocidade angular da componente lenta em 1,7 por cento e do ganho em 5 por cento. CONCLUSÕES: A latência e a velocidade dos movimentos sacádicos fixos; a latência, a precisão e a velocidade dos movimentos randomizados; o ganho do rastreio pendular; a velocidade angular da componente lenta e o ganho do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica.

AIM: To assess whether or not the parameters of fixed and randomized saccadic movements, of pendular tracking and of optokinetic nystagmus in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction. METHOD: 60 patients with dizziness of peripheral vestibular origin, from 12 to 82 years of age, males and females, were evaluated in the Universidade Federal de São Paulo. Ocular movement parameter findings were compared to a normal pattern. RESULTS: Fixed saccadic movements were altered in 100 percent of the cases as to latency, and in 35.0 percent of the cases as to speed; the randomized saccadic movements were altered in 100 percent of the cases as to latency, in 78.3 percent as to precision, and in 1.7 percent as to speed; the pendular tracking showed a gain alteration in the frequencies of 0.1 Hz in 15 percent of the cases, 0.2 Hz in 21.7 percent, and 0.4 Hz in 13.3 percent; the optokinetic nystagmus showed an alteration of the angular speed in the slow component in 1.7 percent of the cases, and in gain in 5.0 percent. CONCLUSION: Fixed saccadic movement latency and speed, randomized saccadic movement latency, precision and speed, pendular tracking gain, slow component angular speed, and optokinetic nystagmus gain in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction.

Oculomotricidade na infância: o padrão de normalidade é o mesmo do adulto? / Oculomotricity in childhood: is the normal range the same as in adults?

O estudo da oculomotricidade se dá através da avaliação de três sistemas: movimentos oculares sacádicos (MOS), nistagmo optocinético (NO) e movimentos oculares de rastreio lento (MORL). A atuação conjunta destes três sistemas permite a estabilização do campo visual nas diversas situações de movimento às quais o indivíduo é submetido. OBJETIVO: Comparar os valores da oculomotricidade encontrados em crianças e em adultos normais na tentativa de confirmar, ou não, a viabilidade do uso dos mesmos parâmetros de normalidade dos adultos na interpretação do exame de crianças. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: Foram estudados os MOS, o NO e os MORL em 50 crianças e em 35 adultos normais e os resultados foram comparados entre si através do teste t de Student. RESULTADOS: Os dados mostram diferença significativa entre os resultados obtidos nos testes de crianças e de adultos (significativo ao nível alfa = 0,05). DISCUSSÃO: Na literatura encontramos evidências de que a mielinização das vias vestibulares ocorre em torno das 16 semanas e que os tratos piramidais se mielinizam aos 24 meses de idade sendo a oculomotricidade perfeita nessa época. Outros estudos descrevem a importância destes testes na detecção de doenças neurológicas, de alterações visuais e até como preditores do risco de desenvolvimento de esquizofrenia no entanto não trazem os valores de normalidade para a criança. No nosso trabalho encontramos aumento da latência dos MOS, aumento no ganho do NO, diminuição do ganho e aumento do grau de distorção dos MORL em crianças quando comparadas aos adultos o que está de acordo com a literatura. Estas alterações poderiam ser explicadas pela desatenção e pela imaturidade do controle dos movimentos oculares na criança. CONCLUSÃO: Assim, torna-se necessário o estabelecimento de um parâmetro de normalidade para a oculomotricidade na infância para que a oculografia possa ser analisada corretamente, evitando que se interpretem como patológicos resultados esperados para a população infantil.

Correlation between Optokinetic Nystagmus Response and 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.

Fully automatic measurement of 3-dimensional eye movement with video-oculography / 中南大学学报(医学版)

OBJECTIVE@#To bring forward a new method for automatic measurement of the translation and rotation of the eye movement.@*METHODS@#A centroid method, edge filter, and ellipse fitting were used to get the accurate position of the eye center. The rotation angle of the eye was determined by Fourier-Translation arithmetic operators.@*RESULTS@#The simulation image test and initial clinical experiment obtained a good precision.@*CONCLUSION@#This method can eliminate the influence of eyelid overlapping and illumination, which can measure the 3-dimensional eye movement accurately.

A case of transient cortical blindness following coronary angiography / 대한내과학회지

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.

Neuro-Behcet's Disease Presenting with Foville Syndrome : A Case Report

A Foville syndrome is rare. A 46-year-old man with a 3-year history of Behcet's disease presented with a right facial palsy and a limitation in the rightward movements of the eyes. On neurologic examination, there was no movement of eyes in the right hemifield during all kinds of eye movements, including saccade, smooth pursuit, vestibulo-ocular reflex, and optokinetic nystagmus. However, all the eye movements were normal in the left hemifiled except for slowed saccades toward the right. Additional features were right infranuclear facial paresis and extensor plantar response on left side. Brain MRI revealed high signal intensity lesions in the right pons both in the dorsal tegmentum and in the basis. Neurological signs resolved gradually with steroid treatment. Different clinical features between abducens nucleus syndrome and paramedian pontine reticular formation syndrome are briefly discussed. To the authors' knowledge, this is the first case report of a Foville syndrome caused by neuro-Behcet's disease.

Ophthalmological findings in children with hypoxic-ischaemic insults

To evaluate ophthalmological abnormalities in children with brain injury due to prenatal hypoxic ischemic insult, and to correlate these abnormalities with the severity of brain affection. Thirty children below 3 years of age were include in the study. Full ophthalmological examination was done with interest to visual acuity measurement, ocular motility and ocular alignment examination. Neurological assessment was also done. Ophthalmological disorders including defective visual acuity, negative optokinetic nystagmus and strabismus were found in the studied children. An associated was detected between the incidence of these findings and the motor mental development of the children. Ophthalmological examination and follow up is mandatory for children who experienced perinatal hypoxic insults together with their medical and neurological car

The Developement of An Objective Test for Visual Acuity Assessment Using Optokinetic Nystagmus Stimuli Presented Head-Mounted Display: Seohan Objective Visual Acuity Test

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.