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Eye movements associated with eye closure were studied in 36 normal adults, and they were recorded by DC amplifiers of ENG. (1) Eyes moved 64 +/- 17 degrees upward and were adducted 15 +/- 7 degrees when eyes were closed. (2) The vertical eye position was held upwards in 33 persons and slightly turned down in 3 persons. (3) The superior rectus and inferior oblique muscles worked together during eye closure.
PURPOSE: The aim of this work was to evaluate the different grades of squamous metaplasia of the conjunctiva during the clinical course of dry eye syndrome, detecting the most characteristic morphological and morphometric changes by biopsy in order to provide a diagnostic classification. METHODS: The conjunctiva was studied under light microscopy by conventional histological methods and by morphometric analysis in 165 patients and in 33 controls. Patients were classified according to the Schirmer 1 test, break-up time, rose Bengal staining, osmolarity and impression cytology. The epithelium and connective tissue, with their different cells and other structures, were studied. RESULTS: The conjunctiva in dry eye patients showed progressive stratification, hyperplasia, hypertrophy and cellular flattening, with loss of goblet cell density and mucous layer. We found five pathological grades of squamous metaplasia and one normal grade. Clear nuclear alterations (indentation and binucleation) were found in the early grades of dry eye syndrome, but pyknotic nuclei and anucleated cells were only seen in the most severe grades. The smallest epithelial cells were found in the control group and their size increased with the severity of the dry eye syndrome. From the earliest stages to the most severe cases, increases in cellular separation were observed. There was also an increase in the number of inflammatory cells. Blood and lymphatic vessels showed alterations only in the most severe cases. CONCLUSIONS: This is the first grading system proposed for biopsy evaluation of the ocular surface in dry eye patients. These morphological and morphometric studies alone were able, even in the earliest phases of dry eye, to detect the squamous metaplasia that progresses from the surface of the epithelium to the connective tissue. This degenerative or adaptative cellular process was characterized mainly by marked increases in the stratification, epithelial cellular size and a general loss of goblet cells.
For accurate visual information about objects of interest moving slowly in three-dimensional (3D) space, primates with binocular fields use both frontal smooth-pursuit (frontal-pursuit) and vergence eye movements (i.e., depth pursuit) to maintain the images of the objects precisely on the foveae of left and right eyes. Moreover, during head or whole-body movement, both frontal- and depth-pursuit systems must interact with the vestibular system to minimize slip of the retinal images that degrades image quality considerably. The caudal part of the frontal eye fields (FEF) contains many frontal-pursuit neurons. Previous studies have shown that a majority of pursuit neurons there discharge for both frontal pursuit and vergence and carry pursuit-in-3D signals. To understand how vestibular inputs interact with pursuit-in-3D signals, three different experiments that examined the nature of vestibular signals in the caudal FEF are described in this review. A majority of caudal FEF pursuit neurons responded to whole-body rotation with preferred directions similar to frontal-pursuit directions and carried frontal gaze (eye-in-space) velocity signals. They were activated in association with adaptive pursuit eye movements induced by cross-axis pursuit-vestibular interactions. During fore/aft and right/left translation in complete darkness, they were also modulated with preferred directions of many neurons similar to pursuit-preferred directions. Previous studies showed that caudal FEF pursuit neurons also receive visual signals about target motion. Taken together, these results suggest that the caudal FEF coordinates its various inputs to provide signals for accurate eye-movement-in-space commands.
Signaling by the secreted hedgehog, decapentaplegic and wingless proteins organizes the pattern of photoreceptor differentiation within the Drosophila eye imaginal disc; hedgehog and decapentaplegic are required for differentiation to initiate at the posterior margin and progress across the disc, while wingless prevents it from initiating at the lateral margins. Our analysis of these interactions has shown that initiation requires both the presence of decapentaplegic and the absence of wingless, which inhibits photoreceptor differentiation downstream of the reception of the decapentaplegic signal. However, wingless is unable to inhibit differentiation driven by activation of the epidermal growth factor receptor pathway. The effect of wingless is subject to regional variations in control, as the anterior margin of the disc is insensitive to wingless inhibition. The eyes absent and eyegone genes encode members of a group of nuclear proteins required to specify the fate of the eye imaginal disc. We show that both eyes absent and eyegone are required for normal activation of decapentaplegic expression at the posterior and lateral margins of the disc, and repression of wingless expression in presumptive retinal tissue. The requirement for eyegone can be alleviated by inhibition of the wingless signaling pathway, suggesting that eyegone promotes eye development primarily by repressing wingless. These results provide a link between the early specification and later differentiation of the eye disc.
Basic experiments on safety evaluation of 0.3%, 1% and 3% solution of KW-1062 (DE-020 eye drops) were carried out. These eye drops applied topically to rabbits eyes had no undesirable local or systemic effects as follows: 1. Repeated instillations of DE-020 eye drops (One drop every 1 hr for 4 hrs) showed no significant irritation except only a temporary and slight congestion localized at the conjunctivae. 2. Daily instillation of DE-020 eye drops (3 times daily for 28 days) showed no abnormal findings in the eye mucosa, clinical signs, body weight, hematological examination, biochemical examination, autopsy, organ weight and histopathological examination.
The eye and head movements of nine children, ages 6 through 10, were measured in order to establish quantitative characteristics of eye movements and eye-head corrdination patterns of children with normal vision and reading levels. The relationship between saccade amplitude and duration was linear, but the slope of this relationship indicated that saccades in children may have higher velocities than they do in adults. One of three temporal patterns of head and saccadic eye movement occurred during shifts of gaze to visual targets, depending on the temporal and spatial predictability of the target. It is suggested that quantitative measurements such as these could be used to examine developmental characteristics of eye and eye-head movement control.
The present study was designed (1) to clarify whether lateral eye movements appear when eyes are closed as well as when they are open and (2) to examine some possible factors which may affect the phenomenon. Horizontal eye movements of 8 males and 8 females during reflection were recorded by means of electro-oculography. All the subjects showed fewer lateral eye movements in eyes-closed condition than in eyes-open condition, and neither the consistency of direction nor the effect of question types was replicated. These facts cannot be explained by the hemispheric activation hypothesis.
In three monkeys, the right eye was moved from the primary position to a position of 30 degrees to 45 degrees exotropia by suturing the globe to the orbital wall. In two animals perfused immediately following suturing, histological examination showed the medial rectus and its sarcomeres to be lengthened and the lateral rectus and its sarcomeres to be shortened as compared to those of the unoperated control eye. In the third monkey, after exotropia was maintained for 2 months, the muscle lengths changed but the sarcomere lengths were similar to those of the control eye. We interpret this to indicate addition of sarcomeres to the lengthened medial rectus and removal of sarcomeres from the shortened lateral rectus. This adaptation to conform muscle length to eye position may explain the altered eye position which persists following periods of eye deviation due to muscle paralysis, prior surgery, injury, or botulinum toxin treatment.
Video-based eye-tracking systems are especially suited to studying eye movements during naturally occurring activities such as locomotion, but eye velocity records suffer from broad band noise that is not amenable to conventional filtering methods. We evaluated the effectiveness of combined median and moving-average filters by comparing prefiltered and postfiltered records made synchronously with a video eye-tracker and the magnetic search coil technique, which is relatively noise free. Root-mean-square noise was reduced by half, without distorting the eye velocity signal. To illustrate the practical use of this technique, we studied normal subjects and patients with deficient labyrinthine function and compared their ability to hold gaze on a visual target that moved with their heads (cancellation of the vestibulo-ocular reflex). Patients and normal subjects performed similarly during active head rotation but, during locomotion, patients held their eyes more steadily on the visual target than did subjects.
Occupational eye injuries are common and preventable. Between 1985 and 1991, there were 635 work-related penetrating eye injuries among the 2939 cases (22%) reported to the National Eye Trauma System Registry by 48 collaborating centers in 28 states and Washington, DC. The median age of the injured workers was 30 years; 75% were younger than 40 years; and 97% were male. The commonest causes of injuries were projectiles (457 cases), sharp objects (166 cases), blunt objects (60 cases), and blasts (22 cases); these terms are not mutually exclusive. Specific objects causing injuries included nails, wire, screwdrivers, and other hand tools. There was evidence of alcohol use by at least 2% of the injured workers. When they were injured, 6% of the workers were wearing safety glasses; 3% were wearing nonsafety eyewear. Posterior segment trauma, which occurred in 63% of the cases, included vitreous hemorrhage (42%), intraocular foreign bodies (35%), and retinal detachment (10%). Hyphema occurred in 35% and traumatic cataract in 32% of the cases. Initial visual acuity after injury was hand motion or worse in 43% of the cases. National Eye Trauma System Registry data are useful to identify strategies to prevent occupational eye injuries such as wider use of safety glasses and improvement in engineering controls.
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Microstimulation of oculomotor regions in primate cortex normally evokes saccadic eye movements of stereotypic directions and amplitudes. The fixed-vector nature of the evoked movements is compatible with the creation of either an artificial retinal or motor error signal. However, when microstimulation is applied during an ongoing natural saccade, the starting eye position of the evoked movement differs from the eye position at stimulation onset (due to the latency of the evoked saccade). An analysis of the effect of this eye position discrepancy on the trajectory of the eventual evoked saccade can clarify the oculomotor role of the structure stimulated. The colliding saccade paradigm of microstimulation was used in the present study to investigate the type of signals conveyed by visual, visuomovement, and movement unit activities in the primate frontal eye field. Colliding saccades elicited from all sites were found to compensate for the portion of the initial movement occurring between stimulation and evoked movement onset, plus a portion of the initial movement occurring before stimulation. This finding suggests that activity in the frontal eye field encodes a retinotopic goal that is converted by a downstream structure into the vector of the eventual saccade.
BACKGROUND: The Retinal Thickness Analyser (RTA) is intended to detect glaucomatous changes as well as macular pathologies at the posterior pole. We determined the diagnostic accuracy for eyes with manifest glaucoma or macular diseases. METHODS: We examined 71 eyes with long-term, established eye conditions. Included were 28 eyes with glaucoma, 21 with different macular diseases and 22 normal eyes. All examinations were evaluated in a blind-test by RTA experts without any clinical information on the patients. After comparison of the RTA interpretation with the clinical diagnosis, we determined sensitivity, specificity, positive and negative predictive values. RESULTS: Of 71 examinations, 15 (21%) were not interpretable. If these results are excluded, the following diagnostic accuracy values were calculated for glaucoma and macular disorders respectively: sensitivity 75 and 59%, specificity 55 and 97%, positive predictive value 48 and 90% and negative predictive value 80 and 84%. These values were not significantly different when both eyes of each patient were included in the final analysis (n=133). CONCLUSION: The diagnostic values of the RTA determined in this case control study were not satisfactory. However, no clinical information was used in the assessment. The extent to which additional clinical information increases the diagnostic value remains to be determined.