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Problemstellung: Diese Arbeit beschäftigt sich mit dem Fallbeispiel einer jungen Patientin, bei welcher vor mehr als zehn Jahren ein Verdacht auf einen Akkommodationsspasmus und Pseudomyopie gestellt wurde. Später zeigt sich, dass es sich um eine Exophorie, die über die akkommodative Konvergenz kompensiert wird, handelt. Es folgen eine Analyse sowie Diskussion der angewendeten Untersuchungs- und Behandlungsmethoden. Methoden: In diesem Kapitel erfolgt die genaue Beschreibung der Untersuchungsmethoden, die bei der Patientin zur Anwendung gekommen sind. Darunter fallen sowohl die orthoptischen, auch der ausschlaggebende 4-Prismen-Basis-Innen-Test, als auch ophthalmologischen Untersuchungen. Ergebnisse: In diesem Abschnitt werden die Ergebnisse der im Patientenfall erhobenen Untersuchungen beschrieben. Des Weiteren wird der Krankheitsverlauf bis zur passenden Therapie dargestellt. Nachdem der 4-Prismen-Basis-Innen-Test positiv ausfiel, wurde eine Prismenbrille verordnet. Diskussion/Schlussfolgerung: Es wird die Literatur mit dem Patientenfall verglichen und mithilfe dessen der Verdacht auf das Krankheitsbild Exophorie, die durch die akkommodative Konvergenz kompensiert wird, bestätigt. Im Rahmen dessen ist die Differentialdiagnose „Akkommodationsspasmus“ ebenfalls Thema dieses Kapitels. Introduction: This paper analyzes the case of a young patient who was suspected of having an accommodative spasm and pseudomyopia more than ten years ago. However, the patient seems to have exophoria which is compensated by accommodative convergence. An analysis and discussion of the performed examination and treatment methods follows. Methods: In this chapter, a detailed description of the methods used during the examination is given. This includes orthoptic as well as ophthalmological examinations. In addition to these, the decisive 4-prism base-inside test was done also. Results: This chapter describes the results of the examinations carried out in the patient's case. Furthermore, the course of the disease up to the appropriate therapy is presented. After the 4-prism base-inside test was positive, prism glasses were prescribed. Discussion/conclusion: The literature is compared with the patient's case and a suspicion of exophoria compensated by accommodative convergence is confirmed. The differential diagnosis “accommodation spasm” is also part of this chapter.

Einleitung: Die genaue Differenzierung zwischen zwei sehr ähnlichen Krankheitsbildern, stellt eine wichtige Aufgabe und Herausforderung für Orthoptist*innen im Alltag dar, wie auch der Strabismus divergens intermittens und die dekompensierende Exophorie. Das Erkennen und Diagnostizieren dieser beiden Krankheitsbilder ist in der Praxis für das therapeutische Vorgehen und die Prognose der Erkrankung wichtig. Methodik: Für die folgende Arbeit hat sich eine Literaturrecherche als geeignete Methode erwiesen. Die Suche nach Literatur fand sowohl in bekannten Datenbanken wie z.B. Medline und Pubmed, als auch in der elektronischen Zeitschriftenbibliothek bzw. Suchmaschine der Bibliothek und Mediathek der FH Campus Wien statt. Ergebnisse: In diesem Kapitel werden alle Ergebnisse aus der Literaturrecherche bzw. Interpretation aller Ergebnisse in Bezug auf die Fragestellungen erläutert. Außerdem werden hier alle Forschungsfragen beantwortet und die beiden Krankheitsbilder gegenübergestellt in Hinblick auf die Diagnostik und Therapie. Diskussion: Hier werden alle Ergebnisse von den Studien mit der Literatur verglichen und die Meinungen der Autor*innen kritisch hinterfragt. Zusätzlich erfolgt in diesem Kapitel eine kritische Reflexion hinsichtlich des Schreibprozesses. Zusammenfassung: In dem Kapitel erfolgt eine Zusammenfassung der wesentlichen Aspekte und Ergebnisse der gesamten Arbeit und die Beantwortung der Forschungsfragen. Introduction: Knowing the difference between two similar clinical picture is an important task and challenge for orthoptists in everyday life, as well as the intermittent Exotropia and the decompensating Exophoria. The recognition and diagnosis of these two clinical pictures appears to be important in practice for the therapeutic approach and for the prognosis of the disease. Methods: A literature search has proven to be a suitable method for the following chapter. The search for literature was performed in databases such as Medline and Pubmed as well as in the electronic journal library and the search engine of the library and media center of the FH Campus Wien. Results: In this chapter all the results from the literature research and the interpretation of all these results in relation to the questions are explained. In addition, all research questions are answered and the two clinical pictures are compared with regard to diagnostic and therapy. Discussion: Here, all the results of the studies are recorded with the literature and the opinions of the authors are critically questioned. This chapter also includes a critical reflection on the writing process. Summary: This chapter summarizes the main aspects and results of the entire work and answers the research questions.

Problemstellung Diese Arbeit beschäftigt sich mit den Auswirkungen von Smartphones und Tablets auf die Augen von Schüler*innen und Student*innen. Des Weiteren werden Bildschirmzeitempfehlungen für Schüler*innen und Student*innen aufgezeigt, die in der orthoptischen Praxis Anwendung finden können. Methode Zur Beantwortung der Forschungsfragen wurde eine Literaturrecherche gewählt. Um relevante Studien zu finden, wurde eine ausführliche Literaturrecherche in verschiedenen Datenbanken durchgeführt. Ergebnisse In diesem Kapitel werden die Forschungsfragen der Arbeit beantwortet. Relevante Studien, die sich mit Auswirkungen von Smartphones und Tablets sowie mit Bildschirmzeitempfehlungen befassen, werden dargestellt. Diskussion Die Ergebnisse aus der Literaturrecherche werden verglichen sowie mit entsprechender Fachliteratur in Beziehung gesetzt und kritisch betrachtet. Des Weiteren erfolgt eine kritische Reflexion des methodischen Vorgehens. Objective This thesis deals with the effects of smartphones and tablets on the eyes of pupils and students. Furthermore, screen time recommendations for pupils and students are presented, which can be applied in orthoptic practice. Method A literature research was chosen to answer the research questions. In order to find relevant studies, an extensive literature research was carried out in various databases. Results In this chapter, the research questions of the thesis are answered. Relevant studies dealing with the effects of smartphones and tablets as well as screen time recommendations are presented. Discussion The results of the literature research are compared and critically examined in relation to the relevant literature. Furthermore, a critical reflection of the methodological procedure is performed.

From the 1860s onward, ‘eye experts’ increasingly fretted the alleged surge of myopia attributed to an increase of reading matter circulating in schools. In order to avert the inauspicious prospects, revised school desks designed to prevent children from becoming myopic were introduced. During the 1880s, said experts turned to printed matter, maintaining that books must become more reader friendly. Along with the turn to books, a peculiar shift within the hygiene discourse occurred: While the ill addressed by school desk-revisions was myopia, the goal of revising book design was to make reading less tiring. This paper explores both the shift from the hygiene of the eye to the hygiene of reading as well as the materialization of the stipulations and claims made by reading hygienists. In doing so, the paper demonstrates that optimizing the reading process was closely linked to a fear of overburdening and fatigue which expressed itself in the psychopathological discourse of the time.

Visual restrictions can lead to anxiety and possibly to social retirement. Therefore it makes sense to assess the patients' degree of handicap. The goal of the present study was to investigate if patients show changes in their personality or a reduced quality of life as a result of their visual field defect.15 patients with visual field defects were asked to fill out the revised version of the Freiburger Persönlichkeitsinventar (FPI-R) and the National Eye Institute Visual Function Questionnaire (NEI-VFQ). The FPI-R encompasses the standardised recording of many personality traits whereas the NEI-VFQ addresses the visual quality of life.In the total sample all FPI-R scales were appropriate for the study in the inconspicuous standard range. Slight shifts resulted toward increased willingness to make contacts (scale 4, ST 4.2), reduced physical strain (scale 7, ST 4.3) and lower physical discomfort (scale 8, ST 3.7). The size of the visual field defect does not correlate with the satisfaction with life, with the physical discomfort and with the state of health but with the dependency on others (p = 0.047) and with the exertion of their social roles (p = 0.043). The scale "satisfaction with life" of the FPI-R correlated with the scale "psychic condition" of the NEI-VFQ (p = 0.028) and the physical discomfort showed a significant correlation with the scale "eye strain" (p = 0.006) in the NEI-VFQ.Contrary to our presumptions, patients with visual field defects did not show any changes in their personality. It is supposed that they have learned to compensate for their reduced visual functions.

Irlen therapy, visual training, training of ocular motor control, and the correction method of H.-J. Haase represent a diversity of treatment methods that are mainly aimed at dyslexia, fatigue while reading, and general lack of concentration. We summarize the theoretical background of these methods, treatment approaches, and related clinical trials. None of these methods, because of incorrect theoretical concepts and an attempt to simplify the underlying causes, was found to have a specific influence on the patients' complaints. The absence of specific therapeutic effects and the high costs and time expenditure required should discourage practitioners from recommending these methods.

The present paper summarizes a series of ergonomic studies on the relation between asthenopic complaints and binocular vision at the computer workstation. In particular, the paper reports on measurements of the accuracy of ocular convergence during fixation of central fusion stimuli (i. e. fixation disparity) as a function of viewing distance.Different versions of subjective tests for fixation disparity (using dichoptic nonius lines) are presented, including a computer-controlled procedure (the eye-test PC).These new tests suggest that non-presbyopic subjects with normal binocular vision may suffer from asthenopic complaints if they have - in near vision - an exo fixation disparity larger than average.In these cases, the stress exercised on the convergence system can be reduced by using a longer viewing distance at the workplace.

Unlike heterotropia (= manifest strabismus), heterophoria (= latent strabismus) is not a primarily existing condition but is a reaction to an interruption of the sensory-motor feedback control system. The reaction consists of a deviation from the orthovergence position. Binocular vision causes a continuous calibration of the vergence position. This "orthophorisation" explains that in most persons, heterophoria differs only slightly from zero. Nevertheless, a small heterophoria is common (70-80% of the population). The need to compensate for heterophoria by sensory-motor fusion can cause asthenopic complaints, such as headaches with prolonged reading. Since a variety of other defects can lead to similar symptoms, a causal relationship with heterophoria can be assumed only after a thorough differential diagnosis. Prism spectacles or eye muscle surgery for heterophoria should be recommended only after prism trials in free space, which include yoked prisms as a placebo control. Heterophoria should be distinguished from "Winkelfehlsichtigkeit", which is a deviation from orthoposition that results from the "measuring and correcting methodology after H.-J. Haase" (MKH) and is based on the idea that fixation disparity, a minute deviation from orthovergence position, indicates an inability to overcome a larger "vergence angle at rest". Objective recordings have, however, revealed that the subjective tests with stereo cues applied in the MKH can mislead to the assumption of a fixation disparity although both eyes are aligned exactly to the fixation point. A trial conducted in the Netherlands concerning the therapy of asthenopic complaints showed no statistically significant advantage of prism spectacles determined with the MKH over conventional spectacles.

With the coming into force of the new Austrian Employee Protection Act the issue of the so called "computer glasses" will also gain added importance in our country. Such glasses have been defined as vision aids to be exclusively used for the work on computer monitors and include single-vision glasses solely intended for reading computer screen, glasses with bifocal lenses for reading computer screen and hard-copy documents as well as those with varifocal lenses featuring a thickened central section. There is still a considerable controversy among those concerned as to who will bear the costs for such glasses--most likely it will be the employer. Prescription of such vision aids will be exclusively restricted to ophthalmologists, based on a thorough ophthalmological examination under adequate consideration of the specific working environment and the workplace requirements of the individual employee concerned.

Tired eyes even after a short period of strain are well known as asthenopia. This term derives from a Greek expression meaning 'weak eye'. The following reasons are to be taken into account: uncorrected refractional errors such as hyperopia and astigmatism, accommodative and fusional defects and heterophoria, or combinations there of. With many cases of asthenopia the clinical symptomatology may resemble an organic eye disease or an affection of the brain [dry eye, Graves' disease, myasthenia, special form of essential blepharospasm, neurogenic latent eye muscle palsies, narcolepsy]. It is the aim of a precise patient's history to differentiate between functional and organic causes. By means of case reports and diagnostic tools, the development of symptomatology and the therapy are discussed.

Based on their experiences several authors consider an alternating central scotoma as the main reason for reading difficulties due to dyslexia.Searching for a simple and reliable method for determination of an alternating central scotoma we used a pair of synoptophore fusion images, in the center of which we added the letter F respectively L as central control signs. A spontaneously perceived and persisting E means a perfect and stable orthophoria. A persisting F or L with fusion of the images means a one sided central scotoma. Alternation of F and L with fusion of the images means an alternating central scotoma.By examining normal readers, untreated asthenopic and untreated dyslexic patients, we found mostly rapid alternation of F and L in the latter two groups, whereas most of the normal readers saw F, L and E alternating at longer intervals.Thus undisturbed reading seems not to demand perfect orthophoria. On the other hand a rapidly alternating central scotoma may be considered as an important factor causing reading difficulties.

The 30-prism-test is a relatively quick and simple method for many-sided testing binocular behaviour in near distance in patients with reading difficulties and asthenopic symptoms, respecting well known and assumed causes of the disturbances. Therefore indications for treatment are given.

Visual evoked cortical potentials (VECP) elicited with checkerboard pattern reversal stimuli of high spatial frequency and low contrast were recorded. The changes in the VECP depending on the duration of task-oriented activity at video display units (VDU) and in the office were determined. The testing procedure can be used to decide on adequate recovery periods (breaks) for any visual workload and requires only a short time. We investigated 30 probands: 10 subjects tested before and after 4 h of VDU work under controlled standard conditions had statistically significant increases of latency (P0.001) and decreases of amplitude in VECP recordings (P0.05). Another 10 subjects tested at the same intervals but exposed to standard office working conditions also showed statistically significant increases of latency (P0.0001) and decrease of amplitude in VECP recordings (P0.01). The 10 control subjects tested at the same intervals spent the time between recording sessions on leisure activity (walking) and showed no significant VECP changes. Statistical evaluation was performed with Student's t-test for paired samples. Contrast sensitivity (Ginsburg test) decreased in both VDU and office groups after completion of their workload, but remained within normal limits. The maximal changes in refraction amounted to +/- 0.25 D after 4 h and +/- 0.5 D after 6 h and showed no bias. Extended periods of working at VDUs and conventional office work increase the latency and decrease the amplitude of the pattern-evoked VECP. This method can be used to determine optimal scheduling of breaks in for people working at VDUs and doing conventional office work.

Asthenopic complaints frequently occur when visual requirements are high in conjunction with illumination by gas discharge lamps. Four causes should be considered: level of the vision task, quality of light (spectral distribution, fluorescent flicker), quality of illumination, individual characteristics of the affected subject. Of 3000 patients, 58% had asthenopic complaints when exposed to gas discharge lamps. The number of females was twice that of males. The subjects affected were predominantly women, aged 20-30 years, who exhibited autonomic lability. Also, they showed reduced concentration power, diminished binocular and stereo vision, and more than normal photic driving findings in the EEG. Fluorescent flicker exerted no influence on elementary visual power, concentration power visuomotor performance, or optical reaction time. It did have an effect on dynamic visual acuity, flicker frequency, blinking rate, and the demands experienced. Fluorescent flicker should be reduced, e.g., by three-phase connection or electronic ballasts. Correcting the binocular vision and reducing the individual glare sensitivity are approaches indicated for individual therapy.

About 30% of our patients suffering from purely binocular asthenopia showed lower binocular than monocular visual acuity. Cover test examination revealed exophoria at near fixation, which could be regarded to be physiological. Furthermore, the Pola test as well as Graefe's prism diplopia test showed no pathological findings. When given 4 prism base-in, a better binocular acuity was achieved and exophoria at for distance fixation was revealed. Often the prisms base-in had to be increased slowly and an operative treatment was indicated in 80%. The test is described in detail and examples from typical case studies are demonstrated. The importance of the test for understanding asthenopia in cases with heterophoria is discussed.

Subjects with different characteristics of the vergence system resting state (close or distant resting vergence, large and small increase upon depression of the eyes) worked with a VDU in a relatively high and a relatively low position for 1 1/2 hours. The directions of gaze were about -5 degrees and -35 degrees below the horizontal. A shorter observation distance was chosen with the lower VDU position than with the higher one, and it increased during the course of the work. In the high VDU position the increase was particularly strong for subjects with a distant resting vergence. The discrepancy between the angle of convergence during visual work and the resting vergence was larger in subjects with a distant resting vergence than in subjects with close one, and it was larger with the higher than with the lower VDU position (except in subjects with a minimal effect of eye depression on resting vergence). However, corresponding differences in visual fatigue as assessed by means of a questionnaire could not be found. Nevertheless the majority of subjects preferred the low VDU position. A number of additional consequences of a low VDU position support the conclusion that it would be advantageous for many users to tilt the display backward and to sink it below the level of the table surface.

Monocular and binocular reading curves of 20 patients (4 with cataract, 5 with glaucoma, 11 with maculopathy) were recorded by infrared oculography. Reading speed was found to be directly proportional to the visual acuity of the eye tested. However, the same visual acuity in both eyes does not always mean that the subject reads at the same speed with both eyes. For example, paracentral visual field defects impair reading ability and eyes which appear to have good vision may easily become tired. Twelve of 16 examined eyes with maculopathy showed a significant decrease in reading speed during a reading test lasting no more than 2 minutes. In tests of the same duration cataract patients did not tire; their reading speed increased. Binocular vision helps improve reading speed in cases of maculopathy, and even more so in cases of glaucoma with visual field defects. Attention is drawn to Mackensen's suggestion that measurement of reading speed is a valuable function test, and to the fact that in certain cases fatigue of an eye during reading is a new and measurable criterion of the degree of visual impairment.

The accommodation-convergence bar was developed as a simple measuring and exercise instrument. For the ophthalmologist, it is a convenient means of measuring accommodation and convergence in the office, while patients can use it for home convergence and fixation exercises which they can monitor themselves. The A = C bar has also been used experimentally to eliminate the functional central scotoma in dyslexic children.

Visual requirements, in the case of modern technologies, are concerned in particular with control and regulation mechanisms of the visual system. For this reason differentiated analyses of visual requirements are necessary along with comprehensive optometrical care. In the latest official sight capacity criteria D 77, account is taken of these points. Measurements of the strain experienced, the routine of breaks during working hours and the extension of optometrical methods are therefore subjects of current research. Attention needs to be paid to raising the qualification levels and to finding new partners for cooperation.

Ophthalmological examinations of patients with asthenopic complaints should include measurement of fusion in addition to retinoscopy under cycloplegia and testing for heterophoria. If fusion is poor in the absence of heterophoria it is advisable to correct even small refractive errors up to 0.5 D; 63% of such patients are cured of complaints as a result and there is an improvement in almost all the others. On the other hand, only 22% of heterophoric patients are cured of their asthenopia by "weak" glasses, although 64% show an improvement.

Sunlight or light from other sources can be scattered and refracted by the smears left on windshields by wipers. Under certain circumstances the resulting light phenomena can disturb binocular vision and distract the driver's attention.

A new syndrome is described, observed in patients with lachrymal hyposecretion without rheumatoid manifestations. It consists in the association of ocular hypotony, decrease of convergence, and in some cases vitreous retraction, to lachrymal hyposecretion. There is a predominance of this syndrome in females.

Unclear asthenopic complaints are often due to intermittant loss of binocularity. Simple tests are described, based on the characteristic features of physiological binocularity. They can be used to demonstrate an intermittant alternating or unilateral central scotoma which may be the result of the interaction of primarily sensory or primarily motor dysfunctions. Hence particular importance must be attached to using these methods with varying distances and directions of vision. The findings obtained from these tests should be the starting point of therapy.

8,032 workers were ophthalmologically examined. In 10.7% there were asthenopic complaints. In 4.6% the symptoms were caused by environmental factors, in 6.13% by organic factors.

The contribution of ophthalmology in the diagnostic evaluation of a patient with headache is outlined. When asthenopia or an organic eye disease is cause of the headache, the ophthalmologist cannot only diagnose the etiology but can also cure the patient by adequate therapy. When the headache is sign of CNS-disease, the ophthalmologist can provide the neurologist with valuable information regarding nature and localization of the process.

A study was carried out by seven ophthalmologists practising in the Berne region on 473 patients complaining of eye strain. Medical histories were taken by questionnaire, refraction was done and phoria measured, followed by therapy in accordance with the physician's opinion. In 380 cases, glasses were prescribed, including prismatic glasses for 14 patients. In 123 cases, local medical therapy was instituted. The statistica evaluation of pre-treatment findings and results of therapy, was carried out using a computer. The principial complaints before treatment were eyestrain and visual disturbances, followed by conjunctival irritation and headache. Women complained more about headaches, men more about visual disturbances. A majority of the patients with visual disturbances needed minus lenses, while for the treatment of headaches mostly plus lenses were needed. In patients with conjunctival irritation local medical treatment resulted in additional relief of symptoms. Cylindric correction had only a minor influence on the result of therapy. Heterophoric patients did not have more complaints than orthophoric ones, and results with spectacles without prisms were the same as in orthophoric patients.

A deviation between the angle of convergence during visual work and the resting level of the vergence system (vergence discrepancy) should be associated with costs; subjects should tend to reduce these costs by increasing the observation distance. The remaining costs should contribute to visual fatigue. Both hypotheses were tested using a sample of 40 subjects, mainly students. In agreement with the first hypothesis, subjects with large initial vergence discrepancy increased their observation distance more in the course of 1 1/2 hours of visual work than subjects with smaller initial vergence discrepancy. Visual fatigue was assessed using a set of questions developed in two pilot studies. Contrary to the second hypothesis, visual fatigue did not depend on effective vergence discrepancy, that is, the deviation between the resting level of the vergence system and the actual angle of convergence. In addition, such a relationship was not found for further dependent variables (performance, BMS questionnaire, critical flicker frequency, evaluation of conditions of work, postural complaints). The results are discussed with respect to the role of tonic and dynamic components of the vergence system for visual fatigue.

Seventy-three patients with asthenopia and 43 control subjects were examined with the Pola-Test. The two populations showed a significantly different frequency of pathologic results on the four test patterns. The so-called "stereo test" seems to be the most important test pattern. Patients with a pathologic stereo pattern reported asthenopic symptoms significantly more frequently than the control subjects who were questioned for similar symptoms. However, since 30% of the asthenopic patients showed normal results on the four Pola-Test patterns, the indication for treatment can be based only on a combined evaluation of binocular tests and asthenopic symptoms. In asthenopia visual and conjunctival symptoms are more prominent than headache. At times they may be masked by psychogenic factors. In a double-blind study on 12 asthenopic patients symptoms improved significantly during treatment with prisms.

With the introduction of VDU work the frequency of various health problems increased proportionally to an increase in work hours on VDU's. Today the frequency of health problems is still greater, than it is for traditional office work. The observed symptoms are mostly stress reactions of multifunctional cause. Only with a close collaboration of workphysiology oriented physicians and VDU users, using the principles of workphysiology and ergonomics, can a satisfactory solution be reached.