Primary orbital amyloidosis localised to an extraocular muscle.

Primary, localised orbital amyloidosis has been reported previously in only 15 patients. A case with amyloidosis strictly localised to an extraocular muscle is presented.

Work with video display terminals among office employees. IV. Refraction, accommodation, convergence and binocular vision.

The present study is the fourth of a major epidemiologic health investigation on work with a video display terminal (VDT). The other studies showed that VDT operators replying to questionnaires have more eye discomfort than a reference group of office employees not employed in VDT work and that women have more eye discomfort, musculoskeletal complaints, headache, and skin disorders than men. Routine ophthalmologic examinations failed to establish any appreciable differences between the groups; for example, the prevalence of myopia was the same. In the present study, the VDT operators and referents were examined before and at the end of work sessions for changes in refraction, accommodation, convergence capacity, and binocular vision such as heterophoria and fusion range. No differences could be established between the VDT operators and the referents.

Work with video display terminals among office employees. III. Ophthalmologic factors.

The present ophthalmologic study is the third part of a major epidemiologic health investigation on work with a video display terminal (VDT). An initial study showed that VDT operators replying to a questionnaire reported more eye discomfort than a reference group not employed in VDT work and that women reported more eye discomfort, musculoskeletal discomfort, headache, and skin disorders than men, irrespective of whether or not they were employed in VDT work. In the present study the ophthalmologic history of eye diseases and eye discomfort yielded a much lower percentage response for symptoms and discomfort than the questionnaire, and, just as with visual acuity and refraction, there was no difference between the exposed and reference groups or between the men and women. The exposed subjects were found to be overcorrected in terms of presbyopia addition in relation to work distance. As regards ocular examination findings, low frequency rates were noted for pathological lens opacities. Opacities of this kind were slightly more frequent among the VDT operators than among the referents, but the difference was not statistically significant. There were no other differences in the ocular findings of the exposed and reference groups.

A modified letter matching chart for testing young children's visual acuity.

A new chart for testing children's visual acuity was designed. It was based on the matching principle and showed rows of the four letters H, O, T, and V at a distance of 3 m. A geometric progression of leter size was used. In order to disclose the crowding phenomenon, the distance between letters was equal to the letter width in each line. Fifty children's testability and visual acuity was studied with this chart and an E chart. It was found that the children performed better when the letter matching chart was used and that the letter matching visual acuity values were higher in about 2/3 of the eyes. The more interesting matching game and the closer viewing distance are possible causes of these differences.

Investigation of visual strain experienced by microscope operators at an electronics plant.

This investigation was concerned with the examination of 75 microscope operators at an electronics plant, with reference to eye function and visual strain. It consisted of three separate parts: (1) standardised interviews dealing with symptoms of visual strain, (2) examinations of the refractive state as well as possible diseases of the eye, and (3) examination of binocular vision. It emerged that 80% of the microscope operators engaged in full time microscope operation experienced various symptoms of visual strain. A statistically verified relationship was found to exist between these manifestations of visual strain on the one hand and uncorrected astigmatism, fusion insufficiency (poorer eye co-ordination) and the length of time spent at the microscope during the working day on the other.

Working with cathode-ray tube based visual display units.

Eye strain when working with visual display units might be due to bad ergonomics but also to eye functions not meeting the demands. If the symbol on the screen has a 4 mm height and the working distance is 60 cm, a visual acuity of 0.4 is required. However to read with ease in the long run a visual acuity of 0.7 is needed. Therefore the employee's visual acuity and refraction must be examined when newly employed, at the age of forty, then every fifth year and when having problems. Other eye dysfunctions could be revealed from questionnaires.