Eye Bar Research Articles

Effect of myopia management contact lens design on accommodative microfluctuations and eye movements during reading

BackgroundSoft contact lenses have been developed and licensed for reducing myopia progression. These lenses have different designs, such as extended depth of focus (EDOF) and dual focus (DF). In this prospective, double-masked, cross-over study, different lens designs were investigated to see whether these had impact on accommodative microfluctuations and eye movements during reading. MethodsParticipants were fitted with three lenses in a randomised order; a single vision (SV) design (Omafilcon A2; Proclear), a DF design (Omafilcon A2; MiSight), and an EDOF lens design (Etafilcon A; NaturalVue),. Accommodative microfluctuations were measured at 25 cm for at least 60s in each lens, using a Shin-Nippon SRW-5000 autorefractor adapted to continuously record accommodation at 22Hz. Eye movement data was collected with the Thomson Clinical Eye Tracker incorporating a Tobii Eye bar. Eye movements include fixations per row, fixations per minute, mean regressions per row, total number of regressions, and total rightward saccades. Accommodation data was analysed using power spectrum analysis. Differences between the lenses were compared using a related sample two-way Friedman test. ResultsTwenty-three participants (18–29 years) were recruited to take part. The average mean spherical error was −2.65D ± 1.42DS, with an average age of 23.4 ± 3.5 years. No significant difference for accommodative microfluctuations was found. Significant differences were found for fixations per row (P = 0.03), fixations per minute (P = 0.008), mean regressions per row (P = 0.002), and total number of regressions (P = 0.002), but not total rightward saccades (P = 0.10). Post-hoc analysis indicated the EDOF lens results were significantly different from the other lenses, with more regressive eye movements observed. ConclusionsRegressive saccades appear to increase when wearing EDOF lens designs, which may impact visual comfort. Further studies in children, over a longer period of adaptation are necessary to assess the potential impact of this finding on daily reading activities in children.

Eye Bars - Pins Connections

This type of connections was used from the beginning of the steel constructions and is very efficient in some typical cases. Connections with eye bars and pins were used initially in suspension bridges, cantilever truss girders and other structures. In modern steel structures this type of connection is often used in cases when simple solutions are necessary like scaffoldings, mobile structures, emergency bridges, etc, or cases in which a certain rotation (pin connection) is desired like structures on cables, chimney, cable stayed bridges and bowstring bridges. At the end of the 19th century and the beginning of the 20th century, when the technology of foundation was not yet developed, engineers preferred the cantilever arrangement (known also as the Gerber system) to the continuous bridge, because it has favourable moments along its length and is not subjected to settlement stresses. It is important to mention that the cantilever truss girder is easier to analyse. However a cantilever arrangement requires special hinge connections and is less rigid than a continuous one. Some famous bridges have been built in this system. One of these structures of the past is the Traians bridge over the Mures in Arad, erected in 1910. The main cantilever truss has the following spans: L = 50,05 + 85,30 + 50,05 = 185,40 m. After two World Wars and other damages the bridge is still in operation for usual traffic - cars and tramways (with restrictions for trucks). The bridge is a historical monument of the engineering science and has a remarkable aesthetic aspect and an emblematical importance for the city of Arad. One of the aspects of the rehabilitation project is the analysis of the Gerber hinge which consists of lug plates and bolts in order to assure the movement of the suspended central part of the structure. These elements have to support the reaction force from all the loads on the bridge and they have a complex stress distribution. Due to the different events, the increasing of the traffic and traffic loads, the existence of cracks in these plates is possible and probable. The paper includes also the evaluation of the technical state of the bridge, stress evaluation based on 3D analysis, assessment of the remaining fatigue life.

Orbital lymphoma: a simple treatment using electrons

Previous papers have discussed the successful treatment of orbital lymphoid tumors using a low-vacuum contact lens placed directly on the eye and the use of a lead bar suspended over the eye with a retort stand. In this paper, a novel approach using a cerrobend bar attached to an electron shield for the treatment of a conjunctival lymphoma is presented. With this approach, the entire eye, excluding the lens, may be treated with a single field. Isodose distributions measured in a water phantom are compared with those planned on a 3D radiotherapy treatment planning system, where the effects of an external eye bar can be shown. The clinical outcome of the treatment is also shown.

Evidence for glutamatergic mechanisms in the vagal sensory pathway initiating cardiorespiratory reflexes in the shorthorn sculpin Myoxocephalus scorpius.

Glutamate is a major neurotransmitter of chemoreceptor and baroreceptor afferent pathways in mammals and therefore plays a central role in the development of cardiorespiratory reflexes. In fish, the gills are the major sites of these receptors, and, consequently, the terminal field (sensory area) of their afferents (glossopharyngus and vagus) in the medulla must be an important site for the integration of chemoreceptor and baroreceptor signals. This investigation explored whether fish have glutamatergic mechanisms in the vagal sensory area (Xs) that could be involved in the generation of cardiorespiratory reflexes. The locations of the vagal sensory and motor (Xm) areas in the medulla were established by the orthograde and retrograde axonal transport of the neural tract tracer Fast Blue following its injection into the ganglion nodosum. Glutamate was then microinjected into identified sites within the Xs in an attempt to mimic chemoreceptor- and baroreceptor-induced reflexes commonly observed in fish. By necessity, the brain injections were performed on anaesthetised animals that were fixed by 'eye bars' in a recirculating water system. Blood pressure and heart rate were measured using an arterial cannula positioned in the afferent branchial artery of the 3rd gill arch, and ventilation was measured by impedance probes sutured onto the operculum. Unilateral injection of glutamate (40-100 nl, 10 mmol l(-1)) into the Xs caused marked cardiorespiratory changes. Injection (0.1-0.3 mm deep) in different rostrocaudal, medial-lateral positions induced a bradycardia, either increased or decreased blood pressure, ventilation frequency and amplitude and, sometimes, an initial apnea. Often these responses occurred simultaneously in various different combinations but, occasionally, they appeared singly, suggesting specific projections into the Xs for each cardiorespiratory variable and local determination of the modality of the response. Response patterns related to chemoreceptor reflex activation were predominantly located rostral of obex, whereas patterns related to baroreceptor reflex activation were more caudal, around obex. The glutamate-induced bradycardia was N-methyl-D-aspartate (NMDA) receptor dependent and atropine sensitive. Taken together, our data provide evidence that glutamate is a putative player in the central integration of chemoreceptor and baroreceptor information in fish.

Role of radiotherapy for primary orbital lymphoma.

To define the role of radiation therapy of primary orbital lymphoma, a retrospective analysis was undertaken for 18 patients with primary orbital lymphoma who were treated with curative radiotherapy between 1984 and 1995. The histology was found to be low grade lymphoma in 11 patients, intermediate grade in 7. All patients were of Ann Arbor stage IE, but bilateral involvement of the orbit was observed in 3 patients (16.6%). Anatomical subsites involved were the retrobulbar, eyelid, and conjunctiva in eight, five, and four patients, respectively. The median radiation dose was 30 Gy ranging from 20 Gy to 50 Gy. Twelve of 18 patients received a radiation dose of 30 Gy or less. To properly protect the lens during irradiation, the contact lens blocks were used for nine patients with conjunctival and eyelid tumor or the hanging eye bar blocks were applied for eight patients with retrobulbar tumor. Chemotherapy was given for seven patients with intermediate-grade malignant lymphoma. Two patients had been treated by surgery before referral.

Primary radiotherapy for localized orbital MALT lymphoma

Purpose : To define the natural history, prognosis, and radiocurability of localized orbital extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Methods and Materials : Clinical records and pathologic material of 40 patients treated with local radiotherapy for localized orbital lymphoma were reviewed. Treatment consisted of 30–40 Gy in 1.8–2-Gy fractions (mean 34 Gy) of irradiation using 9–20-MeV electrons for conjunctival lesions, or 6-MV photons with complex treatment planning for retrobulbar lesions. The lens was routinely shielded with the use of a suspended eye bar. Results : Upon pathologic review, 31 cases of orbital MALT lymphoma were identified. With the median follow-up of 5.9 years (range 9 months–20.3 years), the actuarial 10-year overall survival was 73%. Local control was 100%. Five distant failures resulted in a projected 10-year freedom from relapse of 71%. Most of the failures were extranodal in sites where MALT lymphoma has previously been shown to arise. No difference in outcome was observed among patients treated to less than or equal to 34 Gy vs. those treated to higher radiation doses. Two patients experienced clinically significant retinal damage after doses ≥ 34 Gy. Conclusion : In this study, localized orbital MALT lymphoma was well controlled with radiotherapy. Even following relapse, patients with orbital MALT lymphoma exhibited an indolent course. Relapse occurred predominantly in extranodal mucosal sites, implying a possible homing mechanism for MALT lymphoma cells. Given the excellent local control rates, our current treatment recommendation is to use a radiation dose of 30–30.6 Gy in 1.5–1.8-Gy fractions to minimize risk of late toxicity.

States and Restoration of Railway Truss Bridge of 114 years in age

The paper deals with the pin-connected railway truss bridges, which were used for as longas 114 years across Daiyagawa River. The authors present their brief history, structuralfeatures, and deterioration of structural parts which was caused by such a long service, especially wearing of pins and holes in eye bars. Also the restoration works for preservationis described.

Changes in female colour across the ovulatory cycle in the brook stickleback, Culaea inconstans (Kirtland)

The colour signal of the female brook stickleback (Culaea inconstans) is a mosaic of five components: intensity (1) and distribution (2) of black colouration on the body, presence or absence of gold colouration on the body (3), degree of development of the black eye bar (4), and colour intensity of the black dorsal spines (5). These components interact to produce three mosaics corresponding to the stage reached by a female in her ovulatory cycle. Nonbreeding individuals display a silver ventral surface, grey–green dorsal and lateral surfaces bearing dark grey, reticulate variegations, no eye bars, and noncoloured fins and spines. Interspawning-interval females develop a silvery gold ventral surface, light grey, spotted dorsal and lateral surfaces, narrow eye bars, noncoloured fins, and dark spines. The intensity of a female's body and spine colour is positively correlated with her aggressive response to an intruding male. Spine colour intensity is also positively correlated with her aggressive response to an intruding female. Courting females project a distinct signal comprising a pink–gold body, medium grey dorsal and lateral swirls, no eye bars, and noncoloured fins and spines. The golden courting female contrasts with the velvety black courting male, enhancing the exchange of information about species, sex, and sexual motivation via the two nuptial signals.

Temporal changes in the structure of the male nuptial signal in the brook stickleback, Culaea inconstans (Kirtland)

Within the Gasterosteidae, only members of the clade Culaea + Pungitius + Gasterosteus contain nuptially coloured males. Of these males, the nuptial signal has been subjected to detailed experimental examination in one species, the three-spined stickleback, Gasterosteus aculeatus. Since most components of the signal did not originate in G. aculeatus, descriptions of signal structure and variability for other members of the Gasterosteidae are a critical prerequisite to discussions of the processes underlying the evolution of male nuptial colouration in these fish. In this paper I investigated the changes in the male nuptial signal for another member of the clade, the brook stickleback, Culaea inconstans. The results of this investigation revealed that as in G. aculeatus, the signal is a complex mosaic, in this case representing the interaction between changes in the intensity of black pigmentation in the ventral – lateral body surface, the dorsal – lateral body surface, the eye bar, the fins, and the spines. These variables interacted to produce four distinct male colour mosaics corresponding to the stage a male had reached in the breeding cycle and the sex of an intruding conspecific.

Field study of Haplochromis burtoni: Quantitative behavioural observations

Haplochromis burtoni observed in their natural habitat behave differently from those observed in aquaria in several respects. The majority of the territorial males observed in Lake Tanganyika living in a colony did not have the characteristic black eye bar as a part of their bright coloration, although otherwise the colour markings were identical. Those animals with eye bars appeared to be at a disadvantage in competition with barless fish for territories. The non-territorial males, females and juveniles are uniformly cryptically coloured and remained together in two or three large schools on the edge of the colony. These schools drifted slowly through the colony area, attempting to feed in the territories. Territorial males solicited females and chased non-territorial males. Sequences of behavioural events performed during courtship varied, depending on the local population density. Sound recordings showed no purposeful sounds associated with any behavioural acts.

Quantitative behavioural observations of Haplochromis burtoni under semi-natural conditions

Adult males of the cichlid fish Haplochromis burtoni were observed under semi-natural conditions. Nineteen behaviour patterns were recorded simultaneously with the coloration of the fish. Territorial males spend about one per cent of their time maintaining territories. Their interactions with females follow a fairly regular pattern. The bright body coloration and black head markings are rarely turned off, and then only in specific behavioural situations. Surprisingly, there were no differences observed between the males with and the one without the black eye bar, although this has been shown to be a recognized signal in experiments using dummies. In general, the coloration is closely correlated with the status of the animal and less closely with the immediate behavioural situation.

The Results Obtained from Tests of Full-Sized Steel Eye Bars

About two years ago the writer had occasion to note some rather large differences in ultimate strength in tests of full-sized steel eye-bars, as compared with the small specimen tests of the same material. Full sized bars of moderate sections showed losses in ultimate strength of from 5000 to 10000 pounds per square inch, and quite notable decreases in elastic limit also. After investigating these results carefully until satisfied of the facts, the comparison was extended to quite a series of other tests, and the conclusion was reached that these losses were the rule and not the exception, and that they were frequently large.