Efeitos da anisometropia induzida experimentalmente na binocularidade de crianças portadoras de leve ambliopia

Ribeiro, Geraldo de Barros; Almeida, Henderson Celestino de; Brooks, Steven Elliot

doi:10.5935/0004-2749.19990018

RESUMO

Objetivo:

O objetivo desse estudo foi analisar os efeitos da anisometropia na visão binocular em crianças normais e portadoras de discreta ambliopia.

Métodos:

20 pacientes com idade entre 6 e 12 anos, que não possuíam estrabismo foram estudados. Todos tinham pelo menos 40 segundos de arco de estereopsia. 10 pacientes tinham acuidade visual normal (controle), e 10 tinham leve ambliopia monocular. A interação binocular foi medida pelo estereoteste de Titmus e o teste de Worth 4 pontos de luz -W4D. Miopia, hipermetropia e astigmatismo a 90° e 45° (variando de 1 a 4 graus) foram induzidos unilateralmente em cada indivíduo usando armação de prova.

Resultados:

Todos os indivíduos, independente do grupo, demonstraram uma diminuição na função binocular com o aumento dos níveis de anisometropia. Isto foi detectado pelo aumento da área de supressão no teste de W4D e no decréscimo da estereoacuidade no teste de Titmus. Não houve diferença dos valores medianos da estereopsia entre os grupos em nenhum nível de anisometropia.

Conclusão:

Pequenos graus de anisometropia podem causar significantes alterações na função binocular em crianças. Leve ambliopia monocular parece não afetar significativamente essa relação.

Palavras-chave:
Binocularidade; Anisometropia; Ambliopia

SUMMARY

Purpose:

To determine the effect of experimentally-induced anisometropia on binocular function in normal and mildly amblyopic children.

Methods:

A total of 20 nonstrabismic patients ranging in age from 6 to 12 years were studied. All had at least 40 arc seconds of stereopsis. Ten subjects had normal visual acuity (controls), and 10 had mild unilateral amblyopia. Binocular interaction was assessed by measurement of stereoacuity (Titmus circles) and Worth four-dot fusion test. Unilateral myopia, hyperopia or astigmatism (at 90 and 45 deg) were induced in each subject using trial lenses, ranging from 1 to 4 diopters.

Results:

All subjects, regardless of group, showed a decline in binocularfunction with increasing levels of anisometropia, as evidenced by increased suppression on Worth 4-dot and decreased stereoacuity on Titmus testing. There was no difference in median stereoacuity between groups for any type or level of anisometropia.

Conclusion:

Even low degrees of induced anisometropia may cause significant abnormalites in binocular function in children. Preexisting mild amblyopia does not seem to significantly affect this relationship.

Keywords:
Binocularity; Anisometropia; Amblyopia

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REFERÊNCIAS BIBLIOGRÁFICAS

¹
Townshend AM, Homes JM, Evans LS. Deth of Anisometropic Ambliopia and Difference in Refraction. Am J Ophthalmol 1993; 116:431-6.
²
Brooks SE, Johnson D, Fissche, Johnson D, Fischer N. Anisometropia and Binocularity. Ophthalmol 1996; 103:1139-43.
³
Abrahamsson M, Sjõstrand J. Natural History of Infantile Anisometropia. Br J Ophthalmol 1996;80:860-3.
⁴
Ingram RM, Traynar MJ, Walker C, Wilson JM. Screening for refractive errors at age 1 year: a pilot study. Br J Ophthalmol 1979;63:243-50.
⁵
Daw NW. The Friendald Lecture. Mechanisms of Plasticity in the Visual Cortex. Invest Ophthal Visual Sci 1994;35:4168-79.
⁶
Ikeda H, Tremain KE. Amblyopia resulting from penalisation: neurophy-siological studies of Kittens reared with atropinisation of one or both eyes. Br J Ophthalmol 1978;62:21-8.
⁷
Wiesel TN, Hubel DH. Single-cell Responses in Striate Cortex of Kittens Deprived of Vision in One Eye. J Neurophysiol 1963;26:1003-17.
⁸
Scott WE, Mash J. Stereoacuity in Normal Individuals. Ann Ophthalmol 1974;6:99-101.
⁹
Levy NS, Glick EB. Stereoscopic Perception and Snellen Visual Acuity. Am J Ophthalmol 1974;78:722-4.
¹⁰
Simons K. Stereoacuity in Young Children. Arch Ophthalmol 1981;99:439-45.
¹¹
Lam AKC, Chau ASY, Leung GYO, Man BSH. Effect of Naturally Occurring Visual Acuity Differences Between two eyes in Stereacuity. Ophthal Physiol Opt 1996; 16: 189-95.
¹²
Vries JD. Anisometropia in Children: analysis of a hospital population. Br J Ophthalmol 1985;69:504-7.
¹³
Stigmar G. Blurred visual stimuli II. The effect of blurred visual stimuli on vernier and stereo acuity. Acta Ophthalmol 1971;49:364-79.
¹⁴
Ogle KN. Spatial localization through binocular vision, in Davson H (ed): The Eye IV. Visual Optics and Optical space Sense. New York. Academic Press Inc, 1962;289-90.
¹⁵
Colenbrander MC. The Limitts of Stereopsis Vision. Ophthalmologica 1948; 115:363.
¹⁶
Burian HM. Stereopsis. Doc Ophthalmol 1951 ;V-Vl: 169.
¹⁷
Donzis B, Rappazzo A, Burde RM, Gordon M. Effect of binocular variations of Snellen's Visual Acuity on Titmus Stereoacuity. Arch Ophthalmol 1983; 101:930-2.
¹⁸
Parks MM. Stereoacuity as an indicator of bifixation. In Strabismus Symposium, Giesse, August 1966. Arruga A editor. NY/ Switzzerland, Basel S Karger 1968; pp.258-60.
¹⁹
Katz M. The Human Eye as an Optical System. In Tasman W., Jaeger EA, eds. Duane's Clinical Ophthalmology. Philadelphia; J.B. Lippicott Company 1985;69:504-7.
²⁰
Parks MM. The monofixation syndrome. In Symposium on Strabismus. Transaction of The New Orleans Academy of Ohthalmology. St. Louis, C.V. Mosby 1971; p.141.

Datas de Publicação

Publicação nesta coleção
Jun 1999

Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que o trabalho original seja corretamente citado.

[1] ¹
Townshend AM, Homes JM, Evans LS. Deth of Anisometropic Ambliopia and Difference in Refraction. Am J Ophthalmol 1993; 116:431-6.

[2] ²
Brooks SE, Johnson D, Fissche, Johnson D, Fischer N. Anisometropia and Binocularity. Ophthalmol 1996; 103:1139-43.

[3] ³
Abrahamsson M, Sjõstrand J. Natural History of Infantile Anisometropia. Br J Ophthalmol 1996;80:860-3.

[4] ⁴
Ingram RM, Traynar MJ, Walker C, Wilson JM. Screening for refractive errors at age 1 year: a pilot study. Br J Ophthalmol 1979;63:243-50.

[5] ⁵
Daw NW. The Friendald Lecture. Mechanisms of Plasticity in the Visual Cortex. Invest Ophthal Visual Sci 1994;35:4168-79.

[6] ⁶
Ikeda H, Tremain KE. Amblyopia resulting from penalisation: neurophy-siological studies of Kittens reared with atropinisation of one or both eyes. Br J Ophthalmol 1978;62:21-8.

[7] ⁷
Wiesel TN, Hubel DH. Single-cell Responses in Striate Cortex of Kittens Deprived of Vision in One Eye. J Neurophysiol 1963;26:1003-17.

[8] ⁸
Scott WE, Mash J. Stereoacuity in Normal Individuals. Ann Ophthalmol 1974;6:99-101.

[9] ⁹
Levy NS, Glick EB. Stereoscopic Perception and Snellen Visual Acuity. Am J Ophthalmol 1974;78:722-4.

[10] ¹⁰
Simons K. Stereoacuity in Young Children. Arch Ophthalmol 1981;99:439-45.

[11] ¹¹
Lam AKC, Chau ASY, Leung GYO, Man BSH. Effect of Naturally Occurring Visual Acuity Differences Between two eyes in Stereacuity. Ophthal Physiol Opt 1996; 16: 189-95.

[12] ¹²
Vries JD. Anisometropia in Children: analysis of a hospital population. Br J Ophthalmol 1985;69:504-7.

[13] ¹³
Stigmar G. Blurred visual stimuli II. The effect of blurred visual stimuli on vernier and stereo acuity. Acta Ophthalmol 1971;49:364-79.

[14] ¹⁴
Ogle KN. Spatial localization through binocular vision, in Davson H (ed): The Eye IV. Visual Optics and Optical space Sense. New York. Academic Press Inc, 1962;289-90.

[15] ¹⁵
Colenbrander MC. The Limitts of Stereopsis Vision. Ophthalmologica 1948; 115:363.

[16] ¹⁶
Burian HM. Stereopsis. Doc Ophthalmol 1951 ;V-Vl: 169.

[17] ¹⁷
Donzis B, Rappazzo A, Burde RM, Gordon M. Effect of binocular variations of Snellen's Visual Acuity on Titmus Stereoacuity. Arch Ophthalmol 1983; 101:930-2.

[18] ¹⁸
Parks MM. Stereoacuity as an indicator of bifixation. In Strabismus Symposium, Giesse, August 1966. Arruga A editor. NY/ Switzzerland, Basel S Karger 1968; pp.258-60.

[19] ¹⁹
Katz M. The Human Eye as an Optical System. In Tasman W., Jaeger EA, eds. Duane's Clinical Ophthalmology. Philadelphia; J.B. Lippicott Company 1985;69:504-7.

[20] ²⁰
Parks MM. The monofixation syndrome. In Symposium on Strabismus. Transaction of The New Orleans Academy of Ohthalmology. St. Louis, C.V. Mosby 1971; p.141.

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