Biomedical Engineering Reference
In-Depth Information
The importance of the role played by vision must be understood by all operators. We
usually tend to interfere with the visual abilities of the patient, observing him in a non-
structured environment, during interviews or during functional assessments. In each of
these conditions, the response we expect from the visual system may vary consistently,
although there is no clear evidence of this happening. Observing the patient as he/she com-
fortably explores objects in a room should not lead us into believing that a similarly appro-
priate scanning pattern can reproduce the same situation as the patient is asked to explore
images on a piece of paper at a 30-cm distance from his/her face. This situation often proves
to be correct, but this is not always the case. If not, we run the risk of blaming a more central
limitation to create some constraints that could be avoided using a targeted approach.
The other point that deserves our attention is that we never have to rely on the functional
assessment of vision. Experience shows that even in the worst cases, except the blindness
cases, the visual residue can be used, no matter how big or small it is, to undertake all
activities and to use all of the instruments suggested. Sometimes it will be necessary use
very specific technical tools, such as twin prisms; other times it will be necessary to use
unorthodox solutions, which usually prove themselves to be effective.
As far as the skill of the optometrist is specifically concerned, we underline the impor-
tance of experiencing the environment of the assistive technologies. The professional role
of an optometrist needs to mix with the requests of the operators, who want the optom-
etrist to tell them which path to follow. Optometrists must be also able to recognize their
limits when it comes to suggesting certain solutions, as in clinical case 2. Although the
functioning of the vision and the limits of the patients are clear to the professional, only an
empirical assessment will permit determining the best solution.
In conclusion, the optometrist has various tools to assess each aspect of the vision.
However, in this sector we will usually find ourselves in the condition of literally having
to reinvent tools for very special cases. We always have to take into account the present
function and not just the quantification of the patient's deficiency.
Summary of the Chapter
Vision is a complex process that combines several subprocesses and involves various ana-
tomical structures. The analysis of visual abilities made by the optometrist should always
provide some basic information in a way that allows other ATA team specialists to adapt
their interventions. In the first of the five sections of the chapter, the anatomical structures
and physiology of the visual pathways are briefly described. The second section describes
the basic visual skills that contribute to efficient vision and the methods used to investigate
it. The third section examines the importance of the optometrist as an expert who is able to
select the information necessary for the implementation of the process of ATA. In the fourth
section, two clinical cases are described and the assessment procedures used in the cases
are explained. In the last section special techniques of visual training are briefly described.
Acknowledgments
The authors thank Loreti Alessandra for figure drawings.
 
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