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At least 253 records · Page 14Linked to original sources
PubMed1997

Pattern reversal visual evoked potentials in eyes with macular holes and their fellow eyes.

PURPOSE: To investigate whether the pattern reversal visual evoked potential can be useful in the diagnosis and management of macular hole patients. METHODS: The pattern reversal visual evoked potential was measured in 66 patients with a macular hole and in 43 healthy control subjects. Check sizes of 34', 17' and 10' were applied. RESULTS: Results showed that, for the check sizes of 34', 17' and 10', eyes with a macular hole had significantly prolonged N80 and P100 latencies and a significantly reduced P100 amplitude as compared to their fellow eyes. Furthermore, for the 10' check size, the fellow eyes appeared to have a significantly reduced P100 amplitude in comparison with the control eyes, whereas N80 and P100 latencies of the fellow eyes of the macular hole patients were not prolonged. CONCLUSION: Significant pattern reversal visual evoked potential alterations were shown in eyes with macular holes and fellow eyes for small check sizes.

Aged↗
PubMed2002

Sodium hyaluronate eye drops of different osmolarity for the treatment of dry eye in Sjögren's syndrome patients.

AIM: To study the effect of the treatment of dry eye in Sjögren's syndrome patients with hypotonic or isotonic hyaluronate eye drops. METHODS: 40 Sjögren's syndrome patients were divided in two groups and treated as follows: group 1 with hypotonic (150 mOsm/l) 0.4% hyaluronate eye drops; group 2 with isotonic 0.4% hyaluronate eye drops. The eye drops were instilled six times a day for 90 days. Grading of subjective symptoms, break up time (BUT), corneal fluorescein staining, conjunctival rose bengal staining, Schirmer's I test, and conjunctival impression cytology were carried out at 0 and 15, 30, 90 days from the beginning of the study. Patients were examined in a blind fashion. For the statistical analysis the Student's t test, Mann-Whitney U test, and chi(2) test were performed. RESULTS: Symptoms were statistically significantly improved at day 15 in both groups but group 1 patients had a global score statistically significantly better group 2 (p=0.02). At day 15 group 1 patients had an improvement from baseline values of BUT (p=0.003), fluorescein, and rose bengal score (p=0.000001 and p=0.0004 respectively). Group 2 patients had, at day 15, an improvement of BUT and fluorescein score compared to baseline values (p=0.05 and p=0.0001 respectively). A comparison between the two groups showed better results for group 1 patients at day 15 for rose bengal stain (p=0.01) and for BUT (p=0.05) and fluorescein score (p=0.0003) at day 90. The conjunctival impression cytology showed that group 1 had a statistically significant better total score than group 2 starting from day 15 and lasting throughout the study (p<0.02). Also group 2 patients showed an improvement from baseline values starting from day 30 (p=0.000005). CONCLUSION: Hyaluronate eye drops are useful for treating severe dry eye in Sjögren's syndrome patients. The use of a formulation with pronounced hypotonicity showed better effects on corneoconjunctival epithelium than the isotonic solution.

Adult↗
PubMed1995

Real time binocular detection of horizontal vertical and torsional eye movements by an infra red video-eye tracker.

So far it has only been possible to detect horizontal and vertical eye movements during real time; torsional eye movements have to be calculated from video-tape that have been processed several times, and each investigation takes considerable time. We developed a real time binocular infra red video eye tracker for routine clinical examination which allows real time graphical visualization of horizontal, vertical and torsional eye movements with a bandwidth of 12 Hz (25 Hz refresh frequency). Eye movements in three dimensions can now be obtained as easy as has been done before with electronystagmography for the horizontal component. In contrast to previous systems described, we analyze only those parts of the video-frame that are essential for detection of all three eye movements. This results in a huge data-reduction accompanied by a speed-up of analysis. The black pupil centre is detected by an iterative process of analyzing several horizontal and vertical lines of the even video field. The algorithm searches for regions of minimal intensity. Horizontal and vertical eye rotation is then calculated and transformed into Fick's coordinates. Based upon the centre of the pupil four concentric segments are defined in the iris to detect torsion and to enable correction for false rotation. Torsion is detected by cross-correlation of each segment and estimated from the outcome of the correlation coefficients. All transformations are established by predefined stored transformation matrices thus making real time calculations for transformation unnecessary. After corrections for eccentricity and assuming that fixation of the subjects tested was perfect, accuracy appears to be within 0.3 degrees-1.0 degrees for all three dimensions. Linearity after all corrections is within 4-9% within a visual field of 60 x 40 degrees (horizontal x vertical).

Computer Graphics↗
PubMed1996

An eye imaginal disc-specific transcriptional enhancer in the long terminal repeat of the tom retrotransposon is responsible for eye morphology mutations of Drosophila ananassae.

Optic morphology (Om) mutations of Drosophila ananassae are semidominant, neomorphic and nonpleiotropic, map to at least 22 loci scattered throughout the genome, and are associated with the insertion of the tom retrotransposon. Molecular and genetic analyses have revealed that eye morphology defects of Om mutants are caused by the ectopic or excessive expression of Om genes in the eye imaginal discs of third instar larvae. It is therefore assumed that the tom element carries tissue-specific gene regulatory sequences which enhance expression of the Om genes. In the present study, we examined whether or not the long terminal repeats (LTR) of the tom element contain such an eye imaginal disc-specific enhancer, using D. melanogaster transformants containing a lacZ gene ligated to the tom LTR. Analyses of lacZ gene expression in the eye imaginal discs of third instar larvae of 18 independently established transformant lines showed that the tom LTR was capable of enhancing lacZ expression in all the transformant lines, but the degree of enhancement varied between lines. In addition, the effect of the tom LTR lacZ gene evidently changed when the tom LTR construct was relocated to different chromosomal positions. On the basis of these findings, it is hypothesized that ectopic and excessive expression of the Om genes in the eye imaginal discs is induced by an eye imaginal disc-specific enhancer present in the tom LTR, the effect of which may be subject to chromosomal position effects.

Animals↗
PubMed2003

Eye movement baseline oscillation and variability of eye position during foveation in congenital nystagmus.

Despite the inability to maintain steady fixation, congenital nystagmus does not necessarily reduce visual acuity, that can be achieved during the foveation periods. The duration of the foveation period, but also the cycle-to-cycle variability of eye position and velocity during foveations play an important role. A quantitative relationship that relates visual acuity with foveation time and cycle-to-cycle variability of eye position during foveation has been previously proposed. In many infrared-oculographic and electro-oculographic eye position recordings of our database, a sinusoidal-like oscillation of the baseline was observed, on which the nystagmus waveforms lay. This oscillation may contribute to increase cycle-to-cycle variability during foveations. The aim of this work is to extract the baseline oscillation from the recordings and to verify its relationship with eye position variability during foveation. On the basis of the observations, the baseline oscillation was assumed to be sinusoidal, and was estimated (using a least mean square technique) from eye movement signals recorded during fixation intervals, at different gaze positions, from 20 patients affected by congenital nystagmus with low visual acuity. The average baseline oscillation amplitude was 1.31 degrees, while the average frequency was 0.34 Hz. Baseline oscillation amplitude was well correlated (with a coefficient of 0.66) to the standard deviations of eye-position during foveation, which in turn is connected to visual acuity.

Adolescent↗
PubMed1988

Positional variations in germinal cell growth in pigment-chimeric eyes of Xenopus: posterior half of the developing eye studied in genetic chimerae and in computer simulations.

Growth of germinal cells at different angular positions within the posterior portion of the embryonic frog eye has been examined by orthotopically transplanting small groups of germinal cells from pigmented (stage 30-38) donor embryos into albino (stage 28-36) hosts and then serially photographing the polyclonal-cell progeny domain (typically a black sector) in the pigmented retinal epithelium of the living, growing eye. Far-ventral (6 o'clock) germinal cells formed a narrow sector along the ventral fissure, but ventral germinal cells at a position just posterior to the fissure (7 o'clock on a right eye) were seen to expand rapidly their angular territory on the germinal zone and formed huge sectors that widened toward the front of the older larval eye. Posterior (8, 9, and 10 o'clock) germinal cells were seen to shift their angular positions gradually toward dorsal and formed sectors that appeared to veer dorsalward nearing the front of the older eye. Dorsal (11 o'clock) germinal cells showed attenuative growth, forming sectors that narrowed approaching the front of the older eye. A simulation model of the growth dynamic was used to examine how expansive growth ventrally drives the positional variations in growth. When far-ventral germinal cells were programmed to retain the 6 o'clock position and ventral (7 o'clock) germinal cells were programmed to divide symmetrically at a high probability to produce two daughter germinal cells, not only were the observed ventral chimeric patterns simulated, but also simulated were the attenuative growth of dorsal transplants and the dorsal displacement and veering seen in the growth of posterior transplants.

Animals↗
PubMed2002

The influence of eye muscle surgery on shape and relative orientation of displacement planes: Indirect evidence for neural control of 3D eye movements.

Is Listing's law a consequence of 2D control of eye positioning, where eye torsion is determined by the biomechanical properties of the orbit, or is it a reflection of full 3D neuronal control? This was investigated by observing the influence of a change in mechanical properties of the eye socket on 3D eye movements. The shape and relative orientation of displacement planes were measured using scleral search coils before and after operation of five patients with strabismus. The operation influenced the shape of displacement planes in both eyes of all patients. After the operation, most patients obeyed Listing's law more accurately: a monocular, surgically induced, orbital change caused binocular improvements of torsional control. The relative orientation of planes also changed, but no clear relationship was found between the type of operation and the direction of rotation. The results suggest that Listing's law is not just a result of the biomechanical properties of the eye socket, but has a neural basis.

Adult↗
PubMed1989

Effects of benzydamine eye drops on the rabbit's eye reaction to surgical, physical, and chemical stimuli.

The effects of benzydamine eye drops on the ocular reaction to different irritating stimuli in rabbits are reported. Benzydamine at the concentration of 0.1% reduces inflammatory tissue changes induced by AgNO3 burning of the cornea and inhibits the blood-aqueous barrier breakdown due to peripheral iridectomy or laser irradiation of the iris. Benzydamine reduces the aqueous PGE2 concentration to a similar extent as a 0.5% commercially available eye drop formulation of piroxicam. This result is in contrast with previous in vitro results demonstrating that benzydamine is devoid of any effects on PG synthesis. The possibility that PGE2 reduction is an indirect effect due to other biochemical activities of benzydamine is discussed. In the normal eye benzydamine manifests a local anaesthetic effect which is not accompanied by irritative changes in the anterior segment of the eye, changes in the intraocular pressure or pupillary size. It is suggested that in the clinical use of benzydamine eye drops the local anaesthetic activity may contribute to reducing both the neurogenic component of ocular inflammation and acute pain following injuries to the eye.

Anesthesia, Local↗
PubMed2002

Use of the dry eye questionnaire to measure symptoms of ocular irritation in patients with aqueous tear deficient dry eye.

PURPOSE: To demonstrate the ability of the Dry Eye Questionnaire (DEQ) to characterize the frequency of ocular surface symptoms and their diurnal intensity in patients with Sjögren's syndrome (SS), keratoconjunctivitis sicca (KCS), and age-matched controls. METHODS: One hundred patients with tear-deficient dry eye from Toronto Western Hospital were mailed the DEQ and the McMonnies' questionnaire (MQ). Age- and gender-matched controls were selected from an historical data set. The DEQ measured the habitual frequency, intensity, and impact of common ocular surface symptoms and asked questions about computer use, medications, and allergies. RESULTS: Sixty-two dry eye subjects responded; 30 with SS and 32 with KCS. Compared with controls, SS subjects consistently reported the highest frequency and intensity of symptoms, followed by non-KCS subjects. The intensity of symptoms was significantly greater in the evening than in the morning among SS subjects for all symptoms except dryness and light sensitivity (p < 0.05). Sixty percent of SS subjects reported the need to stop daily activities and close their eyes due to dryness, burning, and light sensitivity. CONCLUSIONS: Symptoms of ocular irritation were frequent and intense among SS and KCS subjects. These symptoms often increased in intensity over the day, suggesting that open-eye conditions affect the progression of symptoms. Measurement of symptom frequency and diurnal intensity by the DEQ provides a sensitive tool that may be useful in clinical treatment trials for dry eye.

Activities of Daily Living↗
PubMed1989

Therapy of corneal erosions and 'dry eye' with Solcoseryl and Vitasic eye drops.

A comparative study of Solcoseryl eye drops versus Vitasic eye drops has been carried out under controlled conditions (randomized and double-blind) on a total of 94 patients. 52 had corneal erosion, 30 had dry eye syndrome, 8 cases could not be evaluated. In addition, 2 eyes with photophthalmia were treated with Vitasic and 2 showing keratitis with Solcoseryl. There were no adverse reactions other than 2 instances of stinging with Solcoseryl and 1 case of severe irritation after Vitasic. The patients were examined on days 0, 1, 3 and 7. Results showed a consistent superiority of Solcoseryl eye drops in respect to speed of healing of corneal erosions and moistening of the cornea in the 'dry eye' syndrome which reached statistical significance in some parameters.

Actihaemyl↗
PubMed1999

Direct regulatory interaction of the eyeless protein with an eye-specific enhancer in the sine oculis gene during eye induction in Drosophila.

The Pax-6 gene encodes a transcription factor with two DNA-binding domains, a paired and a homeodomain, and is expressed during eye morphogenesis and development of the nervous system. Pax-6 homologs have been isolated from a wide variety of organisms ranging from flatworms to humans. Since loss-of-function mutants in insects and mammals lead to an eyeless phenotype and Pax-6 orthologs from distantly related species are capable of inducing ectopic eyes in Drosophila, we have proposed that Pax-6 is a universal master control gene for eye morphogenesis. To determine the extent of evolutionary conservation of the eye morphogenetic pathway, we have begun to identify subordinate target genes of Pax-6. Previously we have shown that expression of two genes, sine oculis (so) and eyes absent (eya), is induced by eyeless (ey), the Pax-6 homolog of Drosophila. Here we present evidence from ectopic expression studies in transgenic flies, from transcription activation studies in yeast, and from gel shift assays in vitro that the EY protein activates transcription of sine oculis by direct interaction with an eye-specific enhancer in the long intron of the so gene.

Animals↗
PubMed2005

Patient expectations regarding eye care: development and results of the Eye Care Expectations Survey (ECES).

OBJECTIVE: To develop an instrument (the Eye Care Expectations Survey [ECES]) that can identify and quantify the expectations of patients visiting eye care providers. METHODS: A total of 202 patients attending 4 ophthalmology practices affiliated with Duke University Eye Center enrolled in the study. All participants completed the pilot version of the ECES, which was developed through a review of the expectations literature and a multicondition focus group process. Factor analysis of patients' responses was used to identify the performance characteristics of the ECES. RESULTS: Factor analysis yielded factors that describe 4 distinct types of expectations: patient involvement in eye care, interpersonal manner, information about diagnosis and prognosis, and communication and clinical competence. These 4 factors explained 89% of the total variance. The factor analysis identified a subset of 27 questions (of the original 37) to represent the 4 factors. Estimates of internal consistency and test-retest reproducibility indicate that the ECES is reliable. In addition, tests of association with clinical variables support the construct validity of the survey. The psychometric properties of the ECES were influenced by the severity of the underlying eye condition as well as other demographic and clinical variables, including the patient's rating of his or her own vision, best corrected visual acuity, sex, education, race, and household income. CONCLUSIONS: Based on this cross-sectional study, the 27-item ECES appears to be a useful tool for better understanding patients' expectations regarding eye care.

Attitude to Health↗
PubMed1981

Vitrectomy in penetrating eye injury. Results of a controlled trial of vitrectomy in an experimental posterior penetrating eye injury in the rhesus monkey.

A controlled trial of pars plana vitrectomy for posterior penetrating eye injury was done in rhesus monkeys. After standard injury, each eye was allocated randomly into a treatment or control group. Treatment groups (ten eyes each) had vitrectomy at 1, 14, or 70 days after injury. The control group had 15 eyes. The same techniques were employed as in human eyes. Surgical objectives were lensectomy, then complete posterior vitrectomy and excision of the anterior vitreous to within 1 or 2 mm of the surface of the peripheral retina and pars plana. Results from this controlled trial provide strong support for the effectiveness of vitrectomy techniques in managing selected posterior penetrating injuries in human eyes and in preventing the complication of traction retinal detachment.

Animals↗
PubMed1978

Development of the compound eyes of dragonflies (Odonata). III. Adult compound eyes.

The distribution of ommatidial diameters and interommatidial angles, as determined by measuring the angles between the optic axes of adjacent ommatidia, are mapped across the surface of the compound eyes of a variety of species selected for different adult behaviors, developmental histories, and taxonomic positions. The size of the visual fields, prey capture foveas, foveas composed of large dorsal ommatidia, and other specializations in the numbers of ommatidia that view various directions in the visual field are discussed in relation to adult behavior. Advanced species have less resemblance between their larval and adult eyes than primitive species. In contrast to their larvae, adults increase the monocular resolution of each eye at the expense of binocular vision. Most species have foveas which view in approximately the anterior direction, instead of in a region of binocular overlap, and many species have foveal bands which view along the horizon. Some advanced perching species, which approach their prey and other odonates from below, have an additional vertical foveal band that views along a vertical plane from the anterior direction to a more dorsal direction. The most unusual foveal band is seen in active flying species. The large dorsal ommatidia of the migratory Anax junius, which cover approximately one third of the eye surface, view a narrow region of the visual field that extends along a plane from the most lateral direction of one eye to a dorsal direction, and continues without interruption to the most lateral direction of the other eye.

Animals↗
PubMed1989

Saccadic reaction times, eye-arm coordination and spontaneous eye movements in normal and MPTP-treated monkeys.

The oculomotor performance of monkeys was investigated before and after destruction of nigrostriatal dopamine neurons by MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). Stimulus-triggered saccades and their relationships to arm movements were measured in a reaction time task. Spontaneous eye movements were recorded while monkeys sat in a primate chair and looked around the laboratory without performing any task. In the reaction time task, saccades and arm movements were commonly triggered by the rapid, visible and audible opening of a small food-containing box which was located at a constant position in front of the animal at eye level. Median saccadic latencies ranged from 68 to 118 ms in intact animals. Saccades were followed by onset of electromyographic (EMG) activity in the extensor digitorum communis and the biceps brachii, the prime mover muscles for the following arm reaching movement. Latencies of stimulus-triggered saccades showed an absence of linear relationship to EMG or arm movement reaction time in intact animals (correlation coefficients of 0.15-0.56). This suggests that eye and arm movements were initiated independently from each other in this experimental situation. Treatment with MPTP resulted in 98-99.5% loss of striatal dopamine in both monkeys. This induced a 29-93% increase in saccadic latency in the reaction time task. The sequential occurrence of saccade, EMG activity and arm movement in each trial was preserved, although intervals between onset of saccades and onsets of EMGs and arm movements were prolonged by 53-173% and 33-679% respectively. Onsets of individual saccades remained uncorrelated with onsets of EMG activity or arm movement. Spontaneous eye movements were strongly reduced in frequency and amplitude after MPTP. Administration of the dopamine precursor L-Dopa increased spontaneous eye movements for less than two hours. The severe deficits in stimulus-triggered and spontaneous saccadic eye movements are oculomotor components of hypokinesia arising after MPTP-induced lesions of the nigrostriatal dopamine system in primates. The data are further evidence for a role of midbrain dopamine neurons in behavioral responsiveness and spontaneous activity.

Animals↗
PubMed1986

The effect of attentive fixation on eye movements evoked by electrical stimulation of the frontal eye fields.

Electrical stimulation of the frontal eye fields of the rhesus monkey evokes saccadic eye movements. Both the amplitude of electrically elicited saccades and the threshold current for eliciting them are primarily determined by the location of the stimulating electrode within the frontal eye fields; however, threshold and amplitude also are systematically affected by the monkey's behavioral state when the stimulation is applied. If the monkey is alert, but not performing a task, saccade amplitudes are largest and thresholds are lowest. Conversely, if the monkey actively fixates a visual target, elicited saccades are smaller and threshold currents are higher. Saccades evoked during fixation have slower velocities appropriate for their reduced amplitude. Phase plane plots of eye velocity versus eye position indicate that these saccades are originally programmed to be smaller and slower, and hence are not large saccades voluntarily braked in mid-flight. As opposed to their amplitude and threshold, the direction of electrically evoked saccades is unaffected by the state of fixation. The state of attentive fixation, but not the visual fixation target itself, is the responsible factor for these effects. These results suggest that there is a difference between the state of active fixation and the state of having the eye still in the orbit without active fixation. The oculomotor system in the latter case is relatively more susceptible to signals from the cerebral cortex.

Animals↗
PubMed2003

[Dry eye disease as a complex dysregulation of the functional anatomy of the ocular surface. New concepts for understanding dry eye disease].

INTRODUCTION: Dry eye disease is a disorder of the tear film that results in epithelial damage and in a disruption of the normal homeostasis at the ocular surface. It is widespread and causes symptoms ranging from discomfort to blindness. METHODS: A review of the existing literature was used to compare different past and recent concepts for the understanding of dry eye disease with a focus on aspects of the integrating functional anatomy of the ocular surface. RESULTS: The understanding of the pathogenesis of dry eye disease has proceeded from the mere recognition of a lack of tears to a consideration of their quality and to the concept of wetting of the ocular surface. However, several other aspects as epithelial differentiation, innervation, hormonal status or immune protection contribute to the intact functional anatomy of the ocular surface. Recently it has been recognized that immunologically regulated mechanisms of inflammation represent a primary or secondary pathogenetic factor for dry eye disease. This is conceivably regulated by the cells of the physiological mucosal immune defence system, the eye-associated lymphoid tissue (EALT). Androgens represent an important trophic factor for the ocular surface and their deficiency predisposes to inflammation. CONCLUSION: Dry eye disease represents a complex dysregulation of the functional anatomy of the ocular surface that can start from different alterations (e.g. insufficient secretion, defects in wetting or innervation). Immune-based inflammation is able to interconnect and negatively reinforce these different pathomechanisms, resulting in a vicious circle.

Conjunctiva↗
PubMed1995

Eye movement desensitization and reprocessing in the treatment of test anxiety: a study of the effects of expectancy and eye movement.

Eye Movement Desensitization and Reprocessing (EMDR) is a recently invented technique acclaimed as a major breakthrough for a range of anxiety-related symptoms. To determine the importance of the eye movement and expectancy variables, we conducted a one-hour session with 41 undergraduate subjects (11 males and 30 females) with test anxiety. A 2 (eye movement vs no eye movement) x 2 (high expectancy vs low expectancy) analysis of variance was performed on three dependent measures: (1) Subjective Units of Disturbance Scale (SUDs). (Wolpe, The Practice of Behavior Therapy, 1982); (2) Validity of Cognition Scale (VOC) (Shapiro, 1992); and (3) the Test Anxiety Inventory (TAI) (Spielberger, TestAnxiety Inventory Preliminary Professional Manual, 1977). The data indicate that all subjects, regardless of treatment condition, showed a significant decrease in anxiety on the TAI. Subjects in the eye-movement condition reported feeling less anxious (SUDs) than those in the no-eye-movement condition. We found no significant main effect or interactions for any of the dependent measures for expectancy.

Adult↗