Teste com Cartões de Teller e avaliação da visão funcional em crianças com baixa visão Teller test with functional vision evaluation in children with low vision

Objective: To know the effectiveness of Teller card test along with the functional vision evaluation in low vision preschool children presenting normal or delayed development. Methods: Transversal study comprising patients from the children visual stimulation Ambulatory Service of the Faculty of Medical Sciences, University of Campinas Teaching Hospital, Campinas (SP)(FCM/HC/ Unicamp). The best corrected visual acuity was obtained using Teller cards and functional vision evaluation, independent from the child development. Results: From a total of 143 evaluated children, 65% did not respond to the Teller card test, only to, the functional vision evaluation. Among 143 children, 99 (70%) presented development delay and 44 (30%), normal development. Conclusion : The Teller card test was not enough to evaluate the children visual acuity with development delays, since more than half of them were not responsive to it, making it necessary that they were submitted to a complementary functional visual evaluation. avaliação visão conhecida acuidade mesmas. crianças, 99 (70%) apresentaram atraso no desenvolvimento e 44 (30%) desenvolvimento Conclusão: O Teste com Cartões de para se conhecer a acuidade visual de crianças com atraso em seu desenvolvimento não se apresentou suficiente, pois da metade das crianças avaliadas não foi responsiva ao mesmo, necessitando de complementação de avaliação da visão funcional para a medida da acuidade


INTRODUCTION
T eller card test -visual acuity test -is being applied in preschool children presenting committed development or not, for measuring their angular visual acuity (1) . Patterned for the evaluation of visual acuity in babies, starting from approximately 1 month old, it can be used until the age needed for children with development delays, with or without associated comorbidities or deficiencies (1,2) .
Children with development delays can present neuroperceptive and cognitive difficulties to respond to ophthalmological tests; therefore, psicophysical tests should be provided to them, with the children cooperation and colaboration for the establishment of assertive diagnoses and conducts.
The best functional vision is one of the main objectives of the ophthalmological service. This represents a big challenge in the ophthalmological area (3), once the comprehension of the visual infant behavior is necessary.
Functional vision is a relatively new concept (4), meaning visual capacity on its potentialities. Once vision is a learned function, with its possible qualities to be developed, mainly during the first months of life, when the plasticity of the nervous system is maximum (5), it is interesting for children to be offered situations with visual stimulation, so they can have the opportunity to develop themselves (6)(7)(8).
The functional vision evaluation, as a psychophysical test, is based on the observation of the child spontaneous behavior in ambulatory environments, where the observer presents and suggests evaluative activities. The observer/evaluator, with the knowledge of the infant visual development, interprets their visual behavior (9)(10)(11)(12).
Regarding vision evaluative conditions, the child cognitive capabilities should be considered, so specific incentives can be interpreted (13). Children with development delay may take longer to answer or make it difficult for the evaluator to observe their visual responses.
This study aimed to evaluate the effectiveness of the visual acuity measurement, using the Teller card test along with the functional vision evaluation in children with low vision, with a committed development or not.

METHODS
This is a transversal study developed during the period from december 2010 to june 2012, at the Children Visual Stimulation Ambulatory Service of the Unicamp Teaching Hospital, approved by the Research Ethics Committee under number 1025/2010.
The total sample comprised 143 children with low vision, of which 78 (55%) were male. There was an age variation between zero months old and 5 years and 11 months old, according to their scheduling in the ambulatory service, with no sampling or random selection of cases, having as inclusion criteria the age group mentioned above and the consent term signed by the responsible for the child. The exclusion criterion was total blindness.
The visual acuity was measured using the best optical correction, in a photopic environment, with natural light, separated eyes, by a pedagogue professional, specialized in visual disability and infant visual stimulation, using Teller cards with 38 centimeters of distance. In some cases, it was necessary for the cards to be nearer, according to what is established in the test manual. In the case of unsatisfactory responses, the test was repeated in another occasion.
In complementation to the Teller card test, the functional vision evaluation (table 1) was applied. The information about the children development was obtained from their hospital documentation. Patients with committed development were followed by the neurological pediatric team of the same hospital. Table 1 Data Gathering for the Children Functional Vision Evaluation  The visual functional evaluation was held as a complement to the Teller card test, creating a special score, in a graduation of score 0 to 5.0 for each topic from the vision functional evaluation.

RESULTS
It was considered score above or equal 18, high intensity punctuation, and the visual stimulation was not considered necessary. Score below 18, with low intensity, the visual stimulation was indicated, oriented and followed by an able pedagogue professional (table 3).

DISCUSSION
In this population, there was a significant prevalence of development delay cases, with comorbidities, cerebral damage   (14,15). After being submitted to the Teller card test and functional vision evaluation, 105 children, representing 74% from the total, have received indication for visual stimulation.
Considering these data, it was observed that the functional vision evaluation, as a complement of the Teller card test, can orientate visual therapeutic conducts, being understood that the earlier the visual stimulation intervention is, the better the possibilities of visual development are going to be for each age group researched in this study.
The cognitive, neurological and motor compromise, as well as the difficulty in comprehending the child visual behavior by the evaluator, restraining the communication and interpretation of visual responses, were also observed by other researchers (6,16) in their studies with children in the same age group received in similar environments.
Visual responses are individual processes and the visual improvement depends on the vision integrity (17). During the child development, vision promotes their social and environmental integration; while vision decrease or its non-existence reduces the child capacities to develop themselves in other sensorial aspects, which may affect their psychological, physical, emotional and social behavior (16,(18)(19)(20)(21)(22).
Some authors present the Teller card test as a good option to evaluate the visual acuity of children with development delay (1,6,(23)(24)(25)(26). However, it was observed in this study that using such a test alone was not enough, since more than half of the children were not responsive to it, making it necessary that they were submitted to a complementary psychophysical test.
According to other studies (6,16), there is a wide difficulty in defining the visual compromise or incapacity of these children for their cognitive, neurological or motor limitations, as well as for the difficulty they have in communicating their visual responses, making it difficult the understanding by the involved ophthalmologists and therapeutic professionals.
Sometimes, for a better diagnostic acumen, the follow-up of electrophysiological evaluation in children becomes necessary (27) Furthermore, considering the aspects of the infant development as a way of knowing the expected behaviors for each age group, ophthalmological services are suggested to infants, aiming to broaden the comprehension of the expressions in the evaluated child and their responses to psychophysical tests.
Another interesting aspect to be observed is that, when it comes to children, the ludic must be explored, so the child feels comfortable and collaborative during tests and evaluations, as well as in visual stimulation follow-ups.

AUTHOR CONTRIBUTIONS
Zimmermann, A; Silva SV; Zimmermann, S; Lira PCR and Carvalho MM designed the work, interpreted the data, drafted the manuscript, provided final approval of the version to be published and agreed to be accountable for all aspects of the work.