Ocular accomodation. Studies of amplitude, insufficiency, and facility training in young school children
Sammanfattning: Aims: The purpose of this thesis was to establish the sufficiency of the ocular accommodation and to characterize accommodative problems and related symptoms among otherwise healthy young school children. The purpose was also to evaluate an accommodative facility training technique by studying the effect of the training on relative accommodation.Materials & Methods: Children from a junior level school were invited to participate in an examination of the accommodative function which was then compared to expected age levels. Children aged 9 13 years, referred by School Health Care for near work-related problems and complaining of headaches, blurred vision, asthenopia, loss of concentration, and avoidance of near activity, were also studied. Only children with reduced negative relative accommodation (NRA) and positive relative accommodation (PRA) and/or very slow accommodative facility were included. The subjects used an accommodative facility training technique until they reported that the symptoms had disappeared.Results: The results showed lower amplitudes than expected in a large group of children and not equivalent to the expected age values. More than one third of the children reported subjective symptoms at near. The incidence of subjective symptoms emerged at the age of 7.5 years and there was significant discrimination ability between low amplitude and subjective symptoms.In all of the trained children the symptoms gradually decreased and finally disappeared during the training period. The data showed a significant increase, despite some individual variations, in both mean NRA and mean PRA among all children characterized with accommodative infacility due to an impaired relative accommodation.Conclusions: Accommodation is not as sufficient in young children as expected. Subjective symptoms emerge at the age of 7.5 years and there is a clear relation between accommodative parameters and these subjective symptoms. Clear standards for diagnosing an accommodative dysfunction need to be further refined. The results also indicate that accommodative facility training is an effective method resulting in loss of symptoms and that it also has a real effect on the relative accommodation in patients with impaired relative accommodation. Because accommodative dysfunctions may result in subjective symptoms, it is of great importance to identify this dysfunction to prevent unnecessary near vision problems.
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