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At least 19 recordsLinked to original sources

[Eye movements in schizophrenia--relationships among eye movements under three experimental conditions; closed-eye, pursuit, and exploratory].

In order to investigate the pathophysiology of schizophrenia using psychophysiological indicators of eye movements, this study was conducted to clarify relations among eye movements under three experimental conditions; closed-eye, pursuit, and exploratory eye movements. Thirty-five chronic schizophrenic patients diagnosed by DSM-III-R criteria and 32 normal controls were examined. Horizontal eye movements were recorded electrooculographically with the subjects under two experimental conditions; one with eyes closed ("Closed-eye Eye Movement," Closed-eye EM), and the other with visually tracking a moving pendulum ("Pursuit Eye Movement," Pursuit EM). The closed-eye condition was further divided into two sub-conditions; one with the subjects awake and at rest, and the other with the subjects in the presence of a repetitive sound. Exploratory eye movements were recorded with an eye-mark recording system while the subjects viewing "S"-shaped geometric figures ("Exploratory Eye Movement," Exploratory EM). Indicators of eye movements under the three experimental conditions described above were measured and the correlations among them were investigated. Clinical symptoms in schizophrenics were assessed by BPRS, SANS and SADS and studied with the Factor Analysis method. In the Closed-eye EM, rapid eye movements appeared significantly more frequently and slow ones were less frequent in schizophrenics than in normals under both sub-conditions. The results for schizophrenics did not change significantly with the addition of sound stimuli. In the Pursuit EM, both the number and amplitude ratio of saccades were significantly larger in schizophrenics than in normals, although these indicators gradually decreased in both groups when tasks requiring concentration were demanded. In the Exploratory EM, the number of eye fixations, the total eye scanning length, and the "Responsive Search Score (RSS)," which is the total number of sections on which the eyes fixed during the response to the confirmative question, were all significantly smaller in schizophrenics than in normals. In schizophrenics, there were significant negative correlations between the RSS of the Exploratory EM and the number of rapid eye movements of the Closed-eye EM, the RSS and the number, amplitude ratio of saccades of the Pursuit EM, respectively. On the contrary, in normals, significant positive correlations were found between the number of rapid eye movements and the number of saccades.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Functional analysis of an eye enhancer of the Drosophila eyes absent gene: differential regulation by eye specification genes.

Genes involved in eye development are highly conserved between vertebrates and Drosophila. Given the complex genetic network controlling early eye development, identification of regulatory sequences controlling gene expression will provide valuable insights toward understanding central events of early eye specification. We have focused on defining regulatory elements critical for Drosophila eyes absent (eya) expression. Although eya has a complex expression pattern during development, analysis of eye-specific mutations in the gene revealed a region selectively deleted in the eye-specific alleles. Here we have performed detailed analysis of the region deleted in the eye-specific eya(2) allele. This analysis shows that this region can direct early eya gene expression in a pattern consistent with that of normal eya in eye progenitor cells. Functional studies indicate that this element will restore appropriate eya transcript expression to rescue the eye-specific allele. We have examined regulation of this element during eye specification, both in normal eye development and in ectopic eye formation. These studies demonstrate that the element was activated upon ectopic expression of the eye specification genes eyeless and dachshund, but does not respond to ectopic expression of eya or sine oculis. The differential regulation of this element by genes involved during early retinal formation reveals new aspects of the genetic hierarchy of eye development.

Animals↗

Effect of eye position within the orbit on electrically elicited saccadic eye movements: a comparison of the macaque monkey's frontal and supplementary eye fields.

1. We quantitatively compared the effects of eye position within the orbit on saccadic eye movements electrically elicited from two oculomotor areas of the macaque monkey's frontal lobe cortex: the frontal eye field (FEF) and the supplementary eye field (SEF). 2. The effect of eye position on electrically elicited saccades was studied by delivering 70-ms trains of intracortical microstimulation while the monkeys fixated a spot of light. Tests of different fixation points located across a rectangular array were randomly intermixed. Complete experiments were carried out on 38 sites in three FEFs of two monkeys and 59 sites from three SEFs of the same two monkeys. Stimulation currents for the array experiments were usually 10-20 microA above the site threshold; the average current used was 36 microA for FEF and 49 microA for SEF. 3. The magnitude of effect of the initial eye position on the elicited saccade's dimensions was quantified at each site by computing the linear regression of saccadic eye movement displacement on the eye position within the orbit when stimulation was applied. This computation was done separately for the horizontal and vertical axes. We call the resulting pair of regression coefficients "orbital perturbation indexes." Indexes of 0.0 represent elicited saccades that do not change their trajectory with different initial eye positions (constant-vector saccades), whereas indexes of -1.0 represent elicited saccades that end at the same orbital position regardless of initial eye position (goal-directed saccades). 4. The effect of eye position varied across sites. In both FEF and SEF, the orbital perturbation indexes were distributed between approximately 0.0 and -0.5, with the horizontal and vertical indexes highly correlated across sites. 5. The average orbital perturbation indexes were small for both eye fields and were not significantly different. The mean horizontal indexes were -0.13 and -0.16 for SEF and FEF, respectively. The mean vertical indexes were -0.16 and -0.13. Neither SEF versus FEF difference was statistically significant. 6. In both SEF and FEF, sites yielding larger-amplitude saccades generally had larger orbital effects than sites yielding smaller saccades. This relationship accounted for the majority of the variability of the orbital perturbation indexes across sites in both SEF and FEF. 7. These results indicate that SEF and FEF are not distinguished from each other by the orbital dependence of their electrically elicited saccades. Thus they do not confirm the previously hypothesized dichotomy that FEF codes constant-vector saccades and SEF codes goal-directed saccades.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Sensitivities in older eyes with good acuity: eyes whose fellow eye has exudative AMD.

We compared several indices of foveal visual function between two groups of people aged 60 and older. One group was comprised of individuals who had good acuity in one eye, but had a history of exudative aging macular degeneration (AMD) in the other eye. We measured visual function in these individuals' good eyes only. The second group was a normative group; it was comprised of individuals who had good acuity in each eye. None of the eyes which we tested from either group had funduscopic evidence of macular pathology other than macular drusen and/or hypopigmentation. We found that eyes whose fellow eye had suffered from exudative AMD themselves suffered compromised foveal function, even when they retained 20/20 or better acuity. Losses of sensitivity mediated by blue-sensitive cones tended to be greater for 1 degree than for 3 degrees diameter test stimuli. Absolute sensitivity losses at long test wavelengths were probably due to several factors, including decreased effective cone photopigment density. Slow rates of recovery during dark adaptation were associated with the presence of many macular drusen and/or macular hypopigmentation. Eyes whose fellow eye had suffered from exudative AMD had more macular drusen and hypopigmentation than eyes whose fellow eye had not suffered from exudative AMD.

Aging↗

Eye stalks or no eye stalks: a structural comparison of pupal development in the stalk-eyed fly Cyrtodiopsis and in Drosophila.

After emergence from the puparium, stalk-eyed flies of the family Diopsidae rapidly expand their head capsule so that the eyes and optic lobes are displaced at the ends of stalks that extend from the central head. Because the expansion takes place in only 15 minutes, we are especially interested in ontogenetic modifications that may facilitate such a rapid and dramatic change. To examine the pupal development of the brain, we used Bodian staining in the stalk-eyed fly, Cyrtodiopsis whitei and compared it with development in the fruit fly, Drosophila melanogaster, which serves as a "typical" dipteran example without eye stalks. Early in pupal development, the neuropil organization of the two species is fairly similar. In both species, columns are present in the outer medulla and giant fibers are discernible in the lobula plate. In contrast to D. melanogaster, C. whitei shows a small, neck-like constriction between the optic lobes and the rest of the brain. By 20% of pupal development, the divergence is more apparent, and by 30%, the future eye stalk and optic nerve of C. whitei has started to form. During the remaining 70% of development, the initially thick optic nerve narrows, and becomes gradually elongated, eventually coiling and folding throughout the short eye stalk. Similarly, the cuticle of the surrounding region becomes constricted, slightly elongated, and gradually appears more and more densely corrugated, like an accordion bellows. However, except for the formation of the optic nerve, the dense aggregation of cuticle around it, and a shift in orientation of the neuropils, the developmental programs of the two species are remarkably similar. This suggests that only a few aspects of development have been modified during the course of evolution to generate the stalk-eyed phenotype. At eclosion, the imago of C. whitei goes through a pumping process to inflate the eye stalks to their full length. Measurements of the diameter of the optic nerve before and after the expansion reveal only a small decrease. We propose that the cuticular folding of the eye stalk as well as the coiling of the optic nerve prepare the pupa well for the rapid and dramatic eye-stalk inflation after eclosion.

Age Factors↗

Justification of the enucleated eye test with eyes of slaughterhouse animals as an alternative to the Draize eye irritation test with rabbits.

The enucleated eye test (EET) with the isolated eye of rabbits has been recognized as a valuable alternative to the Draize test, because it represents a test system nearest to the in vivo test, without the need to use live animals. In this ex vivo bioassay, three parameters are measured to detect possible adverse eye effects, namely corneal swelling, corneal opacity and fluorescein retention. The measurement of corneal swelling in this assay guarantees a highly objective and discriminative parameter. In combination with the detailed observation of corneal opacity and fluorescein retention, a reliable evaluation of the eye irritation potential of test materials is achieved. However, laboratory animals are still necessary as eye donors. The use of slaughter animals, such as the cow, the pig and the chicken, as possible as eye donors for the EET was therefore examined. From these candidates, the chicken appeared to be the most practicable. 21 reference compounds, ranging from non-irritant to severe irritant, which had been tested previously in a validation study on alternative test methods for eye irritation testing, sponsored by the Commission of the European Communities, were examined in the Chicken Enucleated Eye Test (CEET). When compared with the in vivo EC classification, the CEET correctly classified each of the compounds that must be labelled in the EC as irritant (R36) or severely irritant (R41). In addition, since the CEET recognizes three levels of irritancy rather than two (as in the case of the EC classification) a small number of the compounds were recognized as slightly irritant, which according to the EC classification need not be labelled. It was concluded that this ex vivo test system is highly accurate in the assessment of eye irritation potential without the use of laboratory animals.

Animal Testing Alternatives↗

Who should see eye casualties?: a comparison of eye care in an accident and emergency department with a dedicated eye casualty.

Emergency care for eye complaints is provided both by accident and emergency (A&E) departments as well as by dedicated eye casualty departments. This study examines the role of each type of department and the quality of eye care provided. Significant differences were found between the accident and emergency department and the eye casualty department in the history, examination and management of eye patients. Most notably, there were significant differences in the quality of the assessment in the two institutions. Overall 19% (19/100) of A&E records had an inadequate history, compared with 2% (1/50) for eye casualty records. Fifty-nine per cent (59/100) of A&E records contained a significant examination omission, compared with only 8% (4/50) of eye casualty records. Most of the omissions related to a failure to perform an adequate, yet simple, ocular examination including failure to record visual acuity. In 44% (44-100) of A&E cases visual acuity was not recorded or recorded incorrectly. In comparison acuity omissions in eye casualty were present in only 4% (2/50) of cases.

Adult↗

Sport-related eye trauma: a survey of the presentation of eye injuries to a casualty clinic and the use of protective eye-wear.

The study investigated the workload offered by sport-related trauma to a busy casualty clinic and was carried out in two parts. The first part concerned compiling information about sport-related injuries presenting in 1 year to the outpatient eye clinic at Bradford Royal Infirmary. The second part attempted to investigate the awareness and the use of eye-protectors for squash by the student community of Bradford University, using a questionnaire. The sport-related injuries presenting to the casualty department were classified according to the sport involved. Analysis of the data shows that racquet sports, namely tennis, badminton and squash, jointly formed the highest percentage of presentations. In the case of squash and tennis injuries, follow-up treatment and/or admission to hospital was required in 100% of cases. These injuries could be reduced by wearing adequate eye-protectors. The questionnaire survey showed that only 9% of the squash players wore eye protection whilst playing, of whom 3.37% of the total had suffered lacerating injuries previously. Comparison with previous studies indicates that the pattern of eye injuries presenting to casualty departments, and the awareness of the general public concerning the use of eye-protectors, has not altered in recent years. Unless steps are taken, in terms either of mandatory use of eye-protectors and/or of educating the general public on the possible devastating effects of injury, these preventable injuries will continue to burden already overworked hospital casualty departments, draining both resources and expertise.

Athletic Injuries↗

Perceptions of eye diseases and eye care needs of children among parents in rural south India: the Kariapatti Pediatric Eye Evaluation Project (KEEP).

We conducted 24 focus group discussions for parents and grandparents as part of a population-based survey of ocular morbidity to determine awareness and perceptions of eye diseases in children among parents and guardians of children in a rural south Indian population. Focus group discussions were conducted separately for mothers, fathers and grandparents. They were audiotaped and subsequently transcribed to the local language and English. Content analysis of the focus group discussions was done to identify key concepts, and this yielded five broad areas of interest relating to awareness and attitudes towards: 1) eye problems in children, 2) specific eye diseases in children, 3) vision problems in children, 4) existing health practices, and 5) utilization of services. Vision impairment did not figure in the top ten eye problems cited for children. There was a predominant belief that children below 4 years should not wear spectacles. Strabismus was considered as untreatable and was seen as a sign of good luck. Differing advice provided by the medical community for the same condition was an issue. The discussions also brought out that eye doctors were approached last for eye care, after traditional healers and general physicians. The discussions raise several issues of relevance that eye care programs need to address for better community involvement with programs. This will require a far greater focus than the current curative focus adopted by most programs.

Adolescent↗

Clinical evaluation of twice-daily emedastine 0.05% eye drops (Emadine eye drops) versus levocabastine 0.05% eye drops in patients with allergic conjunctivitis.

PURPOSE: The efficacy and safety of emedastine 0.05% eye drops (Emadine; Alcon Laboratories, Inc, Fort Worth, Texas), a new H(1) antagonist, were studied in comparison to levocabastine 0.05% eye drops (Livostin; Janssen-Cilag N V, Berchem, Belgium) during a twice-daily treatment schedule for 6 weeks in adult and pediatric patients with seasonal allergic conjunctivitis. METHODS: In a prospective, multicenter, randomized, double-masked, parallel group study, 222 patients with allergic conjunctivitis were randomized (221 received treatment) to either emedastine or levocabastine, instilled twice daily for 6 weeks. Patient diaries were completed four times daily (before the morning and evening instillations, at noon, and in the afternoon), and clinical examinations were conducted at regular intervals. Primary efficacy variables of ocular redness and itching and secondary efficacy variables of chemosis, eyelid swelling, patient diary data, and physician's global assessment were analyzed. RESULTS: Both emedastine and levocabastine produced a statistically significant (P =.0001) reduction in itching and redness within 5 minutes of the first instillation. All signs and symptoms improved progressively over the 6-week treatment period. After 7 days of use, and throughout the remainder of the study, emedastine was statistically superior to levocabastine (P <.006) in preventing and alleviating the signs and symptoms (itching, redness, chemosis, and eyelid swelling) of allergic conjunctivitis. CONCLUSIONS: Emedastine 0.05% eye drops administered twice daily are more efficacious than levocabastine 0.05% eye drops in the prevention and treatment of the signs and symptoms of allergic conjunctivitis in adults and children of 4 years and above. Both emedastine 0.05% eye drops and levocabastine 0.05% eye drops were well tolerated.

Adolescent↗

Histopathologic study of changes occurring in eyes with intraocular lens implantation: autopsy eyes, enucleated eyes and corneal buttons.

The clinicopathologic findings in 17 eyes which were surgically enucleated or removed at autopsy as well as the histopathology of 72 corneal buttons removed from eyes with intraocular lenses are described. In four of five autopsy eyes the intraocular lens was well tolerated; however, in all cases, changes related to the pseudophakos were found. In seven of 12 surgically enucleated eyes, postsurgical bacterial or fungal endophthalmitis had developed. On histopathological examination, one eye revealed clinically unsuspected endophthalmitis phacoanaphylactica after extracapsular cataract extraction and intraocular lens implantation. In two cases, choroidal melanoma became evident after cataract extraction and insertion of a pseudophakos. In both cases preoperative ultrasonography was limited to A-scan axial measurements. The 72 corneal buttons were removed from patients with pseudophakic bullous keratopathy; histologically the most striking findings were guttata-like changes in 50% of the specimens and retrocorneal membranes in 13.9% of the specimens.

Aged↗

The circular eye-tracking test. I. Simultaneous recording of the horizontal and vertical component of eye movement in the eye-tracking test.

Almost all of the conventional clinical reports on the eye-tracking test are made on the horizontal component of the smooth pursuit function of oculomotor system; few are made on the vertical component. One reason is that during the conventional vertical eye-tracking test the artifacts caused by movement of the upper eyelids often make it difficult to analyze the data. To overcome this problem the authors have developed a method to record simultaneously the horizontal and vertical components of eye movement in the eye-tracking test, and moreover, to reduce artifacts as much as possible. Our method, the circular eye-tracking test, is performed by means of an apparatus that provides a visual stimulus drawing a circle clockwise, at a rate of 120 degrees/sec, with a radius of 25.5 cm, and viewed at a distance of 70 cm.

Brain Diseases↗

Eye movements associated with eye closure. II. Down turning of eye ball elevation.

DC recordings of horizontal and vertical eye movements of various neurological patients were made in an attempt to specify the mechanism underlying sustained eye ball elevation associated with eye closure. Sudden or gradual down turning of vertical eye ball elevation was seen in the following groups: (1) acute stage of inner ear hypo- or afunction; (2) lateral lesions of the cerebellum; (3) acute stage of cerebellar inflammation, and (4) some cases of cerebral lesions. The following pathway seems to be the simplest which would account for these findings: anterior semicircular canal leads to superior vestibular nucleus leads to brachium conjunctivum leads to oculomotor nucleus leads to superior rectus muscle (ipsilateral) and inferior oblique muscle (contralateral).

Adult↗

Neural responses related to smooth-pursuit eye movements and their correspondence with electrically elicited smooth eye movements in the primate frontal eye field.

1. Intracortical microstimulation of a portion of the monkey frontal eye field (FEF) lying in the floor and posterior bank of the arcuate sulcus evokes smooth, rather than saccadic eye movements. To further explore this region's involvement in pursuit, we recorded from FEF neurons in the vicinity of sites from which smooth eye movements (SEMs) were elicited electrically and studied their responses during smooth-pursuit and saccadic tasks. In this report, we describe the neurons' responses during visually guided smooth pursuit and compare their locations and response properties with those of elicited SEMs. 2. One hundred and ninety-three neurons, recorded from the FEF region in six hemispheres of three rhesus monkeys, were classified as "pursuit neurons". These neurons responded during smooth-pursuit tracking of moving visual stimuli but had no, or only minimal, responses in conjunction with visually guided saccades. Pursuit neurons were located in a small region of the arcuate fundus and posterior bank that overlapped, and extended slightly beyond, the region from which SEMs were elicited with microstimulation. 3. All pursuit neurons had a preferred pursuit direction, and all directions were represented with no strong bias toward ipsilateral, contralateral, up, or down. The directional tuning of 80 pursuit cells was measured quantitatively by testing pursuit in several directions and fitting the responses to a Gaussian function. Tuning indices (the sigma parameter of the Gaussian fit) varied between 13 degrees and 136 degrees. The median tuning index, 44.5 degrees, corresponds to a full width at half maximum of 105 degrees. The ubiquity of selectivity for pursuit direction and the wide distribution of preferred directions indicates that pursuit direction uses a place-code type of representation in FEF; however, the broad directional tuning of most neurons suggests that pursuit direction is given by a weighted average of optimal directions across the population of pursuit neurons active at any given time. 4. In general, the responses of pursuit neurons increased with pursuit velocity. Of 13 neurons formally tested with 2 s of constant-velocity tracking in their preferred direction across a range of target speeds, pursuit velocity sensitivity ranged from 0.24 to 1.42 spikes.s-1.deg-1.s-1, with an average sensitivity of 0.70. This relationship suggests that pursuit neurons represent pursuit magnitude using a rate code; this parallels our previous observation that at most SEM sites, the velocity and acceleration of the electrically elicited eye movements increased as a function of the stimulation current.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

[Epidemiology of severe eye injuries. United States Eye Injury Registry (USEIR) and Hungarian Eye Injury Registry (HEIR)].

BACKGROUND: Both in industrialized and in developing nations, the devastating impact of ocular trauma on society is increasingly recognized. Lacking standardized surveillance systems, however, comparable epidemiological information has not been available previously. METHODS: For several years, the United States Eye Injury Registry (USEIR) and the Hungarian Eye Injury Registry (HEIR) have been collecting data on all types of serious ocular trauma, based on identical operating criteria and using standardized reporting forms. We performed a retrospective analysis comparing the two datasets, containing over 8,400 injuries from the U.S. and over 1,200 injuries from Hungary. RESULTS: Sixty percent of patients in the U.S. and 52% of patients in Hungary were less than 30 years of age, with an at least 80% male preponderance in both registries. The home was the most frequent place of injury in both countries (USEIR: 41%, HEIR: 35%); industrial premises represented no more than 14%. Guns were responsible for 12% of cases in the USEIR (HEIR, 1%). Champagne corks were identified as a unique and relatively common source of eye injury in Hungary (1.4%, as opposed to 0.07% in the U.S.). In the USEIR, 16% of injuries were caused by assault (HEIR, 24%; chi-square value = 36.7, p < 0.0000001). The enucleation rate was 12% in the U.S. and 1% in Hungary. CONCLUSIONS: The different findings in the two countries identify certain areas for the implementation of preventive measures (supplying champagne bottles with warning labels and a coordinated fight against violence in Hungary, stricter fireworks legislation in the U.S., public awareness for home injuries in both countries, etc.). Based on the encouraging results from this study, we plan to continue our efforts using modified reporting forms and an upgraded software. We invite additional countries to adopt the USEIR model.

Adolescent↗