Vergencias fusionales. Exploración e importancia en la práctica clínica / Fusion Vergences. Exploration and Importance in Clinical Practice

La vergencia fusional se define como la vergencia estimulada por la disparidad retiniana que genera un movimiento vergencial para mantener la visión binocular simple, son movimientos binoculares disyuntivos en los que ambos ojos se dirigen en la misma dirección para fijar un objeto y a la vez se desplazan en sentido opuesto. La amplitud de fusión desempeña un importante papel en mantener una visión binocular simple. Los valores fuera de la norma son significativos en el diagnóstico de posibles disfunciones binoculares no estrábicas. Con este artículo se pretende mostrar los diferentes criterios relacionados con la evaluación de la amplitud de las reservas fusionales, cual es la prueba más usada y los rangos considerados dentro de límites normales, para lo que se realizó una búsqueda en diferentes publicaciones y textos de la especialidad(AU)

Fusional vergence is defined as the vergence stimulated by retinal disparity that generates a vergence movement to maintain simple binocular vision, they are disjunctive binocular movements in which both eyes are directed in the same direction to fix an object and at the same time they move in opposite way. Fusion amplitude plays an important role in maintaining single binocular vision. Values outside the norm are significant in the diagnosis of possible non-strabismic binocular dysfunctions. This article aims to show the different criteria related to the evaluation of the amplitude of fusional reserves, which is the most used test and the ranges considered within normal limits, for which a search was carried out in different publications and texts of the specialty(AU)

Study on stereoacuity and associated factors in school children aged 7 to 14 years

Purpose: The study aimed to estimate the prevalence of subnormal stereoacuity in school children and to assess the factors associated with it. Methods: In this prospective cross?sectional study, a total of 2,376 school children without amblyopia and manifest squint were screened by the titmus fly test, Snellen chart, tests for heterophoria, anterior segment examination, and fundoscopy. Children with a manifest squint, amblyopia (best?corrected visual acuity [BCVA] <6/18), and history of ocular trauma or surgery, and one?eyed children were excluded. Cycloplegic refraction was done in children with uncorrected or undercorrected refractive errors, and stereoacuity was assessed again with spectacle correction. Results: The prevalence of normal stereoacuity by titmus fly test was 93.18% with correction of refractive errors. Girls had slightly better stereopsis compared with boys. The subnormal stereoacuity was significantly associated with refractive error (P < 0.00001, significant at P < 0.05), unilateral refractive error (P < 0.00001, significant at P < 0.05), bilateral refractive error (P < 0.00001, significant at P < 0.05), anisometropia (P < 0.00001, significant at P < 0.05), ametropia (P < 0.00001, significant at P < 0.05), lower BCVA (P < 0.00001, significant at P < 0.05), hyperopia (P < 0.05, significant at P < 0.05), and heterophoria (P = 0.014, significant at P < 0.05). The subnormal stereoacuity was positively correlated with the magnitude of refractive error of the eyes. Conclusion: This study underlines the significant impact of identification and correction of refractive errors and squints in school children. The measurement of stereoacuity will be of immense importance and must be included in the screening programs for children

Factores que generan variabilidaden la medida del A/CA / Factors that generate variability in the measurement of the a/ca

El A/CA es la sinergia existente entre la acomodación y la convergencia. Tiene una importante aplicación clínica, por lo que la medición lo más fiable posible de esta relación es de gran importancia. Los diferentesmétodos para medir la heteroforia (Cover Test, Von Graefe, Varilla de Maddox, Thorington) tienen diferentes grados de repetitividad, y los diferentes lentes estímulo generan unas respuestas acomodativasdiferentes, por lo que el empleo de una técnica lo más repetible para medir la foria y estímulos que generenmayor estabilidad de la acomodación son los recomendables para la evaluación del A/CA.

Relationship between Accommodative Convergenceand Convergence is namely AC/A ratio. It´s very important in clinic routine so it has to be measured pretty carefully. Different methods to get the heterophoriahave diverse repeatability, because that we should use a technique which most reliability and wear stimulus lens that yield more stability in the accommodative response.

Effect of Acute Hypobaric Hypoxia on Binocular Fusionin Subjects Having Heterophorias / 항공우주의학회지

BACKGROUND: Heterophoria has been considered a disqualifying condition to flying performance because heterophoria, when exposed to high altitude hypoxia, becomes heterotropia causing double vision. However, there has been no actual evidence supporting this assumption. We investigated the binocular fusional ability and symptoms in the subjects having heterophorias upon exposure to acute hypobaric hypoxia. METHODS: 15 subjects having heterophorias and 7 normal controls were included. All the subjects had exophoria and 1 subject had exophoria and hyperphoria. High altitude hypobaric hypoxic condition was simulated in a decompression chamber. Using Worth 4 dot test we measured the binocular fusional ability. To analyze the quality of binocular vision, we measured the stereoscopic visual acuity. By comparing the data between subjects and controls, we evaluated the binocular vision and fusional ability of subjects having heterophorias. RESULTS: All the subjects and controls showed no disruption of binocular fusion on Worth 4 dot test upon exposure to hypoxia. On the whole, 7 of 15 subjects and 3 of 7 controls showed decreased level of stereopsis without significant differences between the two groups. There were no differences in binocular vision including fusional ability and stereopsis between the subjects and the controls in acute hypoxic condition. CONCLUSION: The subjects with heterophorias had stable binocular fusional ability resistant to acute hypobaric hypoxia, which showed no difference from the normal controls. Conclusively, we could not find any disadvantage in heterophoric persons with regard to flying performance. Visual standards for aviation personnel regarding heterophorias also need to be more lenient.

Cefaleas de localización y compromiso oculares / Headches with ocular localization and involvement

SE REVISAN las cefaleas primarias más frecuentes que comprometen las estructuras oculares y vecinas al globo ocular, las variantes de la migraña y las alteraciones propias del nervio óptico que alteran la función visual y que se acompañan no solamente de síntomas dolorosos sino también de trastornos vasomotores debidos a alteraciones del sistema nervioso autónomo que suelen ser comunes en algunos procesos neurálgicos llamados ahora cefaleas con compromiso disautonómico. En este artículo se comentan los elementos epidemiológicos de las diferentes enfermedades craneales, faciales y oculares que cursan con cefalea; las diferencias clínicas entre las mismas y su presentación semiológica, al igual que algunos elementos terapéuticos. Se discuten además algunos elementos fisiopatológicos de gran utilidad en el análisis de los procesos dolorosos craneofaciales y el perfil temporal de los mismos; también se comentan algunas cefaleas secundarias que comparten con las primarias elementos que se prestan a confusión en la clínica. Finalmente, se hace un análisis de las neuralgias faciales comunes.

The most frequent primary headaches, including migraine variants, and intrinsic optic nerve disorders that produce headache, are reviewed. The latter are often accompanied by autonomic nervous system alterations which lead to vasomotor changes, frequently present in neuralgic processes known as headaches with disautonomic involvement. Epidemiological, semiological, clinical, and therapeutical aspects of different cranial, facial and ocular diseases that produce headache are included. Some physiopathological elements that may help to analyze painful craniofacial processes are discussed. Secondary headaches and common facial neuralgias, on the other hand, are also considered because they may confuse the differential diagnosis.

A Study on the Heterophoria in Emmetropia and Ametropia

The purpose of this study was to examine the heterophoria in emmetropia and ametropia. The subjects were 337 healthy men and women between the age of 20-41 years. In 337 cases, Emmetropia were 135 cases, Ametropia were 202 cases. The entire group was tested for heterophoria with synoptophore. In the ametropia, this test was performed before and after correction of refractive error with glasses. The results were as follows: 1. The incidence of heterophoria was 84.4% in emmertropia, 89.2% in myopia and 91.4% in hyperopia. 2. Exophoria was most common in myopia. But in emmetropia and hyperopia, there was no significant difference between the incidence of exophoria and esophoria. The incidence of hyperphoria and cyclophoria was not significantly different between emmetropia and ametropia. 3. In the ametropia, the size of heterophoria was slightly decreased after correction, but the difference was not significant (p>0.05). 4. There was no correlation between the amount of refractive error and the size of heterophoria (p>0.05).