Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “EYES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMedDate not supplied

Histochemical localization of acetylcholinesterase in the lateral eye and brain of Limulus polyphemus: might acetylcholine be a neurotransmitter for lateral inhibition in the lateral eye?

The distribution of acetylcholinesterase (AChE) in the lateral eye and brain of the horseshoe crab was investigated with histochemical means using standard controls to eliminate butyrylcholinesterase and nonspecific staining. Intense staining was observed in the neural plexus of the lateral compound eye, in the lateral optic nerve, and in various neuropils of the brain. Nerve fibers with moderate to weak staining were widespread in the brain. No somata were stained in either the lateral eye or the brain. The distribution of acetylcholinesterase in the supraesophageal ganglia and nerves of the giant barnacle was also investigated for comparison. Although both the median optic nerve of the barnacle and the lateral optic nerve of the horseshoe crab appear to contain the fibers of histaminergic neurons, only the lateral optic nerve of the horseshoe crab shows AChE staining. Other parts of the barnacle nervous system, however, showed intense AChE staining. These results along with the histochemical controls eliminate the possibility that some molecule found in histaminergic neurons accounted for the AChE staining but support the possibility that acetylcholine might be involved as a neurotransmitter in lateral inhibition in the horseshoe crab retina. Two reasonable neurotransmitter candidates for lateral inhibition, histamine and acetylcholine, must now be investigated.

Acetylcholine↗
PubMed1999

Nedocromil sodium eye drops are more effective than sodium cromoglycate eye drops for the long-term management of vernal keratoconjunctivitis.

BACKGROUND: Vernal keratoconjunctivitis (VKC) is a severe though transient form of ocular allergy, predominant in young males, which requires careful management. Corticosteroids are effective but also cause serious topical side-effects in the eye, such as glaucoma and cataracts. The safer, mast cell stabilizing anti-inflammatories (commonly sodium cromoglycate) therefore have an important role. This parallel group study compared efficacy, tolerability and safety of sodium cromoglycate 2% with nedocromil sodium 2%, administered as one drop per eye four times daily for a period of 5 months. METHODS: Children aged 4-17 years, with a diagnosis of mostly limbal VKC in the last 12 months, entered a 2-week baseline during which they used only artificial tears, and were then randomized to treatment, in groups of 18, on an investigator single-masked basis. Daily symptom diary cards were kept by patients/guardians, and VKC was assessed by the clinician at approximately monthly intervals. Dexamethasone was provided for rescue control of severe symptoms, if needed. RESULTS: A total of 34 patients completed the study. Both trial treatments produced rapid improvements and many ocular signs and symptoms, including Trantas' dots, chemosis, itching, soreness and sticky discharge, were fully controlled by the end of the study. However, nedocromil sodium took effect more quickly, with a significant reduction compared to sodium cromoglycate for itching, grittiness, hyperaemia and keratitis within 6 weeks. In addition, nedocromil sodium was the more efficacious overall (significant vs sodium cromoglycate for hyperaemia, keratitis, papillae and pannus at 22 weeks). Both treatments were well tolerated and without serious adverse effects. Final opinions favoured nedocromil sodium, with full control of VKC recorded for 94% (patient opinion) and 100% (clinician opinion) of this treatment group, compared with 29% and 0%, respectively, in the sodium cromoglycate group. CONCLUSIONS: Nedocromil sodium 2% eye drops is significantly more effective than sodium cromoglycate for treatment of VKC.

Adolescent↗
PubMedDate not supplied

[Plastics on the eye - plastics in the eye. Human-optic materials].

BACKGROUND: Materials of identical or similiar chemical classes are used for contact optics as well as for implantable intraocular devices. All of them derive from the chemistry of industrial product developments. PATIENTS AND METHODS: Materials used in and on the eye should behave indifferent. They should not provoke any reaction in the eye and not themselves be altered by the biological surroundings. For materials used in the eye an especially high purity of the polymers utilized as well as a long term light stability is to be demanded. Optical properties like transparency have to be stable over extended time periods under normal light influence. The long time stability of UV-absorbing additives in the materials used has to be verified. RESULTS: All materials used for IOL's - with the exception of the homopolymer of methylmethacrylate - consist of polymer mixtures forming socalled interpenetrating networks which appear as an uniform material. For the manufacturing of intraocular lense materials standardized or unanimous producer prescriptions are not existing. Based on the different polymer formulations different aging and fatigue properties are the outcome. In addition only inadequate knowledge about the long term light stability of the incorporated UV blockers is submitted. CONCLUSIONS: Polymeric materials used for IOL's should be subjected in addition to the test methods listed in EN-ISO 11 979/5 to chemical, polymeranalytic and mechanical substance examinations. As a standard in such examinations a polymethylmethacrylate, free of methylacrylate is proposed. Examinations of each lot should be compulsory. Identification of all ingredients of the intraocular materials should be prescribed and labeled in line with the revelations of common medical drugs prescriptions. The relevations commit the medical doctor to inform his patient about possible side effects of the intraocular implants.

Biocompatible Materials↗
PubMed1989

[Eye diseases and control of labor. Studies of changes in the eye in labor exemplified by subconjunctival hemorrhage (hyposphagmas)].

The possible significance of subconjunctival bleedings (hyposphagmas) as a symptom for other pathological changes of the eye was studied in a group of 354 postpartum patients. They were found in 10.5% of the cases. A relatively higher frequency occurred in primiparas. No other maternal factors than parity were detected as of statistically significant influence. A slightly higher percentage in mothers with large newborn (above average cranial circumference) indicates a relationship to the necessary bearing-down effort. In a second study, 49 postpartum women with subconjunctival bleeding were examined by an ophthalmologist. Neither any intraocular or retrobulbar bleeding nor any other grievous damage to the eye were found. In accordance with the literature we recommend, that highly myopic pregnant women (even with a previous history of retinal detachment, but ophthalmologically sufficiently treated) should undergo induced delivery. However, the approach to pregnant women with retinal detachment occurring and treated during pregnancy, or to glaucoma-patients with risk to a small remaining visual field, should be more careful. In those cases, a vaginal operative delivery procedure (forceps, vacuum-extraction) is recommended. Nevertheless, one should consider individual wishes of the mother, when striving to diminish the risk to the foetus. The same applies to irrational fears related to previously damaged (and possibly only functional) eye.

Adult↗
PubMed1994

Eye-hand coordination: spatial localization after saccadic and pursuit eye movements.

Subjects produced speeded and unspeeded hand movements to a target location after either saccadic or pursuit eye movements to the target. Hand movements began either aligned with the initial position of gaze or from some other location. Subjects generally underestimated the extent of the pursuit eye movements relative to estimates made after saccades. With speeded hand movements, however, the underestimation was reduced considerably if the hand movements began aligned with a location other than the initial position of gaze. The results reveal details of the mechanisms underlying eye-hand coordination and show that important differences exist in the information used for localization for slow and rapid limb movements.

Journal Article↗
PubMed1997

Efficacy of oxymetazoline eye drops in non-infectious conjunctivitis, the most common cause of acute red eyes.

Oxymetazoline (OMZ) is an alpha-adrenergic agonist which causes potent vasoconstriction in various tissues. Thus, its effects on red eye conjunctivitis induced by histamine and arachidonic acid were tested in rabbit eyes. It was found that a brief conjunctivitis induced by 0.01% of histamine can be eliminated effectively by 0.001, 0.004, and 0.016% of OMZ. The long lasting conjunctivitis induced by 0.3% arachidonic acid can also be markedly reduced by 0.004, 0.008, and 0.016% of OMZ. These results indicate that OMZ is a potent, long acting decongestant for conjunctival red eye syndrome.

Adrenergic alpha-Agonists↗
PubMed1998

Development of a wide field height eye topographer: validation on models of the anterior eye surface.

PURPOSE: The aim of this research was to develop a corneal topographer that determines the shape of the entire anterior surface of an eye without assumptions, and with uniformly high accuracy in the center and periphery. METHODS: Based upon a double projection of two sine wave gratings and analysis of the distortion of the sine wave gratings due to the corneal-scleral shape, point-by-point measurements of surface elevation were obtained with a sample density equal to the pixel density of the CCD-detector. Using this principle, a prototype topographer, called the Maastricht Shape Topographer (MST), was developed. The accuracy and reproducibility of the instrument were evaluated using bispheric models of the anterior surface of the eye. RESULTS: The average accuracy of height measurements was +/- 0.55 micron in the 10-mm central area and +/- 22.50 microns in the periphery (14 to 19 mm). Reconstruction accuracy of the radius of curvature was +/- 0.0155 mm (+/- 0.88 D) in the center and +/- 0.0313 mm in the periphery (sclera). Average height reproducibility standard error was 0.0282 micron in the center and 2.6156 microns in the periphery. CONCLUSIONS: With the MST, unambiguous shape measurements of the entire anterior surface of the eye are possible, with accuracy up to clinically accepted standards. MST is able to measure height over a wide area of 20 mm, with a 6-mm depth of field. The tested prototype of the device can be further improved by the use of custom-made optics in order to increase signal to noise ratio in the periphery of the image. This height topographer could offer a reliable method in cases where shape is of paramount importance, e.g., in (scleral) contact lens fitting and refractive surgery.

Contact Lenses↗
PubMed1981

Is there a ubiquitous growth factor in the eye? Proliferation induced in different cell types by eye-derived growth factors.

In a previous work [1] we showed that a neutral extract of bovine adult retina RE can stimulate the growth and modify the morphology of bovine epithelial lens (BEL) cells in vitro. We were also able to demonstrate that the differences in cell shape are closely related to the cell growth properties induced by RE and are mediated by cytoskeletal protein organization as well as external proteins. In this study, we report the results of further investigations on this retinal extract. We show that it possesses all the characteristics of other growth factors such as promoting proliferation in low serum concentration or of enhancing the colony-forming efficiency of BEL cells considerably. By comparing the morphological response of BEL cells treated with RE with the response of other cells to other growth factors, we propose that the phenotypic modifications are cell specific, but not growth factor specific. We report also that RE has a broad spectrum of activity since it is able to stimulate cells from different origins and species (vascular and corneal endothelial cells, myoblasts, chondrocytes, neuroblastoma cells, and keratinocytes), but not all of them, since it can be toxic for fibroblasts. In this respect, it has an activity similar in many aspects to FGF and EGF, while it differs from them for some target cells. Its action has also been compared with the effects of retinoic acid derivatives and shown to be strikingly different. RE-like activity can be found in other ocular tissues from bovine and other species. The highest growth-promoting capacities were found in extracts of iris, pigmented epithelium with choroid, and vitreous body. The nature of all these extracts has not yet been determined. Since they are prepared in a similar way and since they have similar growth-promoting activity, we postulate that there is an ubiquitous growth factor in the eye called eye-derived growth factor (EDGF) which may play an important role in physiology and pathology of the eye.

Animals↗
PubMed2001

East and west see eye to eye--an elective report.

A summary of personal experiences encountered as a medical student on elective at an eye hospital in China. It bears witness to the possibility of seamless combination of western and traditional Chinese medical practices in the field of ophthalmology. Included are also the acupuncture points used in the treatment of optic atrophy at this particular eye hospital. Address of eye hospital: Zhongshan Ophthalmic Center 54 South Xianlie Road Guangzhou 510060 China Period of elective: 5th January 2001-11th March 2001.

Acupuncture Therapy↗
PubMed1991

Neuronal activity related to visually guided saccades in the frontal eye fields of rhesus monkeys: comparison with supplementary eye fields.

1. The purpose of this study was to analyze the response properties of neurons in the frontal eye fields (FEF) of rhesus monkeys (Macaca mulatta) and to compare and contrast the various functional classes with those recorded in the supplementary eye fields (SEF) of the same animals performing the same go/no-go visual tracking task. Three hundred ten cells recorded in FEF provided the data for this investigation. 2. Visual cells in FEF responded to the stimuli that guided the eye movements. The visual cells in FEF responded with a slightly shorter latency and were more consistent and phasic in their activation than their counterparts in SEF. The receptive fields tended to emphasize the contralateral hemifield to the same extent as those observed in SEF visual cells. 3. Preparatory set cells began to discharge after the presentation of the target and ceased firing before the saccade, after the go/no-go cue was given. These neurons comprised a smaller proportion in FEF than in SEF. In contrast to their counterparts in SEF, the preparatory set cells in FEF did not respond preferentially in relation to contralateral movements, even though most responded preferentially for movements in one particular direction. The time course of the discharge of the FEF set cells was similar to that of their SEF counterparts, except that they reached their peak level of activation sooner. The few preparatory set cells in FEF tested with both auditory and visual stimuli tended to respond preferentially to the visual targets, whereas, in contrast, most set cells in SEF were bimodal. 4. Sensory-movement cells represented the largest population of cells recorded in FEF, responding in relation to both the presentation of the targets and the execution of the saccade. Although some of these sensory-movement cells resembled their counterparts in SEF by exhibiting a sustained elevation of activity, most of the FEF sensory-movement cells gave two discrete bursts, one after the presentation of the target and another before and during the saccade. Like their counterparts in SEF, the sensory-movement cells tended to be tuned for saccades into the contralateral hemifield, but this tendency was more pronounced in FEF than in SEF. The FEF sensory-movement cells discharged more briskly, with a shorter latency relative to the presentation of the target, than their counterparts in SEF. In addition, the FEF sensory-movement neurons reached their peak activation sooner than SEF sensory-movement neurons. Most FEF sensory-movement cells exhibited different patterns of activation in response to visual and auditory targets.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Primate frontal eye field activity during natural scanning eye movements.

1. As we scan an image, saccadic eye movements direct our vision to features that attract our attention. Although it is likely that the frontal eye field (FEF) cortex is an important component of the system generating those movements, most studies of FEF neuronal activity have relied upon visuomotor tasks where the experimental subjects are constrained to look from one spot of light to another. In this study, single-unit activity was recorded in the FEF while monkeys freely scanned a variety of projected images, and that activity was compared with activity evoked during conventional visuomotor tasks. 2. FEF neurons with visual activity in conventional tasks increased their activity during scanning when a portion of the image within their receptive field was targeted for the next saccade, but decreased their activity when a target was chosen outside of the receptive field. 3. FEF neurons with movement-related activity during conventional tasks were also active in association with saccades made during scanning. 4. Visual and movement activity were also studied by creating a task that approximated the conditions during the scanning paradigm (rescan task). This was done by superimposing a moveable spot of light onto the image that had been scanned, and rewarding the monkey for following the light as it recreated the original scan's spatial and temporal pattern of eye fixations. In contrast to the visual activity of neurons during the scanning paradigm, visual activity during the rescan task was unaffected by portions of the image within the cell's receptive field, but increased in response to the appearance of the target light.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Deficits in smooth-pursuit eye movements after muscimol inactivation within the primate's frontal eye field.

To evaluate smooth-pursuit (SP) function in the primate frontal eye field (FEF), microinjections of muscimol, a gamma-aminobutyric acid (GABA) agonist, were used to reversibly deactivate physiologically characterized sites in FEF. SP was severely impaired by deactivation at sites in the FEF's smooth eye movement region (FEFsem) located in the fundus and posterior bank of the macaque monkey's arcuate sulcus. These SP deficits were apparent immediately after the muscimol injection and persisted for several hours but recovered by the next day. SP was most drastically and consistently impaired for directions similar to the injected site's elicited smooth eye movement direction or to the optimal SP direction for its neuronal responses. Targets moving in these directions, usually ipsilateral to the injected hemisphere, were tracked primarily with saccades after the muscimol injection, the peak SP velocity being only 10-30% of preinjection velocity. SP in other directions, including contralateral, was less strongly affected. Initial SP acceleration in response to target motion onset was also significantly diminished, generally by approximately the same proportion as peak SP velocity. In contrast, saccades were largely unaffected by muscimol injections in FEFsem; nor was there an immediate effect on SP when control sites in the saccadic region of FEF (FEFsac) were deactivated, although a SP deficit often appeared 30-60 min after FEFsac injections, possibly reflecting diffusion of muscimol into neighboring FEFsem. These reversible SP deficits produced by muscimol inactivation within FEFsem are similar to permanent deficits caused by large aspiration lesions of FEF and indicate that inclusion of FEFsem is the critical factor determining whether FEF lesions impair SP. The severity of the reversible deficits found here indicates how extremely critical FEFsem is for normal highgain SP.

Animals↗
PubMed2000

Supplementary eye field: representation of saccades and relationship between neural response fields and elicited eye movements.

The functional organization of the low-threshold supplementary eye field (SEF) was studied by analyzing presaccadic activity, electrically elicited saccades, and the relationship between them. Response-field optimal vectors, defined as the visual field coordinates or saccadic eye-movement dimensions evoking the highest neural discharge, were quantitatively estimated for 160 SEF neurons by systematically varying peripheral target location relative to a central fixation point and then fitting the responses to Gaussian functions. Saccades were electrically elicited at 109 SEF sites by microstimulation (70 ms, 10-100 microA) during central fixation. The distribution of response fields and elicited saccades indicated a complete representation of all contralateral saccades in SEF. Elicited saccade polar directions ranged between 97 and 262 degrees (data from left hemispheres were transformed to a right-hemisphere convention), and amplitudes ranged between 1.8 and 26.9 degrees. Response-field optimal vectors (right hemisphere transformed) were nearly all contralateral as well; the directions of 115/119 visual response fields and 80/84 movement response fields ranged between 90 and 279 degrees, and response-field eccentricities ranged between 5 and 50 degrees. Response-field directions for the visual and movement activity of visuomovement neurons were strongly correlated (r = 0.95). When neural activity and elicited saccades obtained at exactly the same sites were compared, response fields were highly predictive of elicited saccade dimensions. Response-field direction was highly correlated with the direction of saccades elicited at the recording site (r = 0.92, n = 77). Similarly, response-field eccentricity predicted the size of subsequent electrically elicited saccades (r = 0.49, n = 60). However, elicited saccades were generally smaller than response-field eccentricities and consistently more horizontal when response fields were nearly vertical. The polar direction of response fields and elicited saccades remained constant perpendicular to the cortical surface, indicating a columnar organization of saccade direction. Saccade direction progressively shifted across SEF; however, these orderly shifts were more indicative of a hypercolumnar organization rather than a single global topography. No systematic organization for saccade amplitude was evident. We conclude that saccades are represented in SEF by congruent visual receptive fields, presaccadic movement fields, and efferent mappings. Thus SEF specifies saccade vectors as bursts of activity by local groups of neurons with appropriate projections to downstream oculomotor structures. In this respect, SEF is organized like the superior colliculus and the frontal eye field even though SEF lacks an overall global saccade topography. We contend that all specialized oculomotor functions of SEF must operate within the context of this fundamental organization.

Animals↗
PubMed1978

Tanderil/chloramphenicol eye ointment in the treatment of the "Red Eye" seen in general practice.

An open study is reported in which 35 general practitioners treated 128 patients suffering from 'Red Eye' with a new eye ointment containing 10% Tanderil(oxyphenbutazone) and 1% chloramphenicol. One hundred and seventeen patients completed the seven day treatment period, in which time 99 had completed resolution of the symptoms and were discharged, the remaining 18 patients needed a longer period of treatment. Eleven patients failed to complete the study period, of whom 5 patients were subsequently referred to a specialist and 6 had their treatment changed by the general practitioner. Six patients showed signs of allergy to the ointment, all of whom were being treated for allergic conjunctivitis. Seventeen per cent of patients had some difficulty in applying the eye ointment or complained of subsequent blurring of vision.

Adolescent↗
PubMed2002

Vax2 inactivation in mouse determines alteration of the eye dorsal-ventral axis, misrouting of the optic fibres and eye coloboma.

Vax2 is a homeobox gene whose expression is confined to the ventral region of the prospective neural retina. Overexpression of this gene at early stages of development in Xenopus and in chicken embryos determines a ventralisation of the retina, thus suggesting its role in the molecular pathway that underlies eye development. We describe the generation and characterisation of a mouse with a targeted null mutation of the Vax2 gene. Vax2 homozygous mutant mice display incomplete closure of the optic fissure that leads to eye coloboma. This phenotype is not fully penetrant, suggesting that additional factors contribute to its generation. Vax2 inactivation determines dorsalisation of the expression of mid-late (Ephb2 and Efnb2) but not early (Pax2 and Tbx5) markers of dorsal-ventral polarity in the developing retina. Finally, Vax2 mutant mice exhibit abnormal projections of ventral retinal ganglion cells. In particular, we observed the almost complete absence of ipsilaterally projecting retinal ganglion cells axons in the optic chiasm and alteration of the retinocollicular projections. All these findings indicate that Vax2 is required for the proper closure of the optic fissure, for the establishment of a physiological asymmetry on the dorsal-ventral axis of the eye and for the formation of appropriate retinocollicular connections.

Animals↗
PubMed1995

Imaginary gaze effects on eye movements induced by linear acceleration: involvement of vestibular induced smooth pursuit eye movement.

We investigated smooth eye movements elicited i) by linear acceleration in a space-fixed imaginary gaze condition (smooth component of eye movement induced by linear motion: LSEM) and ii) during acoustic pursuit of a moving sound source (smooth component of eye movement induced by acoustic pursuit of a sound source: SSPEM). The two conditions were examined using the same test subjects. LSEM and SSPEM performance was found to be positively correlated across the subject population. From the comparison of LSEM and SSPEM we propose the following hypothesis: LSEM consists not only of a pure translational vestibular-ocular reflex (tVOR) component but also of a component based on the perception of otolithic information. Accordingly, this second component is instrumental in the pursuit of an imaginary visual target during linear self-motion.

Acceleration↗
PubMed1996

Visual sensitivity and age-related eye diseases. The Beaver Dam Eye Study.

OBJECTIVE: To evaluate the relationships between visual sensitivity and age-related ocular disorders. DESIGN: Prevalence survey of age-related eye diseases. SETTING: Beaver Dam, Wisconsin. PARTICIPANTS: A total community sample of persons 43-84 at the time of the census (1987-1988) was invited to participate (n = 5.926). MAIN OUTCOME MEASURE: Visual sensitivity was measured by a perimeter. Sensitivities were evaluated with regard to age, sex and age-related eye diseases. RESULTS: Sensitivity was inversely associated with age and was lower in women in each age stratum. Central cataract, cataract surgery, and late age-related maculopathy were significantly related to decreased sensitivity in multivariate analyses. CONCLUSIONS: Visual sensitivity, an indication of the ability of the eye to detect a light stimulus, was diminished in those with central cataract, cataract surgery, and late age-related maculopathy. This may be related to diminished vision in environmental conditions of low illumination. Since visual sensitivity is relative easy to determine, this test may have use as a surrogate to assess functional vision loss. Also, although cataract surgery often leads to improved high contrast acuity, there may be a loss in low contrast settings.

Adult↗
PubMed1999

Assessment of corneal decompensation in eyes having undergone molteno shunt procedures compared to eyes having undergone trabeculectomy.

PURPOSE: To compare the incidence of corneal decompensation after Molteno shunt to trabeculectomy. METHODS: We conducted a retrospective analysis of the corneal status of 55 patients with primary open angle glaucoma. We compared 24 eyes of 24 patients who underwent Molteno tube shunt placement (Group 1) to fifteen eyes of 14 patients with multiple surgical procedures, including a trabeculectomy (Group 2). We also compared Group 1 to 28 eyes of 17 patients who underwent only one trabeculectomy (Group 3). RESULTS: The three groups were similar with respect to age, sex, and intraocular pressure (IOP). The average follow-up time from the last surgery in Group 1 was 17.9 months (1-90 months), 22.4 months (2-63 months) in Group 2, and 19.6 months (1-37 months) in Group 3. The average number of surgeries was 3.0 (1-4) in Group 1 and 2.53 (1-4) in Group 2. The surgeries included trabeculectomy, cataract extraction, combined procedures, penetrating keratoplasty, pars plana vitrectomy, and scleral buckle. The incidence of corneal edema was 50% (12/24)in Group 1, 6.7% (1/15) in Group 2, and 0% in Group 3 (0/28). The average time to corneal decompensation was 21 months in Group 1 (1-120 months) and 15 months in Group 2. CONCLUSION: Patients undergoing Molteno shunt placement have a higher rate of corneal decompensation compared to patients undergoing trabeculectomy.

Adult↗