Use of a prismatic microscope in a low vision patient: a case report and discussion

This is a case involving a 60-year-old retired male patient who formerly had excellent reading skills with corrective lenses but due to progression of his diabetic eye disease was unable to clearly read standard [10 - 12 point] print Arabic newspapers, magazines and books with his prescription reading glasses. With the use of high plus lenses and base - in prism this patient was once again able to read the standard print he encountered in his reading activities

Does physical fitness influence intraocular pressure?

The effects of physical fitness on intraocular pressure, was studied. The study was conducted in two parts. Part 1 consisted of three groups of physically fit subjects, each consisting of 50 subjects. In Part 2 subjects were categorized into control and experimental groups, each consisting of 16 subjects. The experimental group took a supervised exercise programme of three months. Intraocular pressure was measured with the Goldman applanation tonometer. As compared to sedentary subjects, intraocular pressures were lower in those who did moderate or severe exercises. In part one, the difference between group 1 consisting of sedentary and group 3 of physically fit subjects was 1.38 +/- 0.08 mmHg, [p < 0.001]. In part two of this study, after exercise training the experimental group showed a marked increase in their physical fitness. The first difference between control and experimental groups was 0.13 +/- 0.27 mmHg [p > 0.05]. After three months, this difference increased to 0.93 +/- 0.28 mmHg [p < 0.01]. This study concludes that physical fitness reduces intraocular pressure. It would seem reasonable at present not to discourage patients who have glaucoma from light exercise, perhaps, on the contrary, it should be encouraged

The primate frontal eye field and the generation of saccadic eye movements: comparison of lesion and acute inactivation/activation studies

The frontal eye field (FEF) of monkeys has been repeatedly implicated in the generation of saccadic eye movements by various experimental approaches. Electrical stimulation of most of the FEF produces saccadic eye movements, many cells have activities related to saccades, and it has anatomical connections with many other oculomotor ares. Surprisingly, complete lesions of the FEF have remarkably little effect on oculomotor behavior. Only when more cognitive aspects are tested is a deficit clearly detected. In contrast, acute inactivation of the FEF on monkeys with the GABA agonist muscimol produced much more severe oculomotor impairment. This difference is probably due to the acute nature of the muscimol effect, which does not allow time for reorganization of the control of eye movements before testing begins. In addition, acute activation of the FEF with the GABA antagonist bicuculline caused the monkey to make irrepressible saccades of the same dimensions as those electrically elicited at the site. These experiments further confirm the strong involvement of the FEF in the control of saccadic eye movements and fixation.

Significación del fenómeno del Bell en la clínica neurológica / Significant of the Bell`s phenomenon in the neurologic clinics

Con la finalidad de evaluar y definir la presencia del Fenómeno de Bell y sus variantes, además de su utilidad como signo semiológico, se evaluaron dos grupos de individuos; el primero constituido por 120 sujetos sin evidencia clínica o paraclínica de lesión orgánica del Sistema Nervioso Central (S.N.C.), sin limites de edad, pero divididos en decenios, incluyendo 15 sujetos en cada subgrupo; y el segundo constituido por 20 pacientes, que presentaban una sola lesión tumoral del S.N.C., intra o extraparenquimatosa, intracraneal supratentorial; comprobada clínica y paraclínicamente con Tomografía Computarizada (T.A.C.) y/o Resonancia Magnética (R.M.N.). Ambos grupos fueron evaluados según protocolo diseñado para el trabajo, con énfasis en la valoración del Fenómeno de Bell por dos médicos experimentados en el procedimiento. Encontramos que la sensibilidad del Fenómeno de Bell fue de 60 por ciento, la especificidad de 90.83 por ciento, el valor perceptivo positivo de 52.17 por ciento, el valor predictivo negativo de 93.16 por ciento, y la eficiencia del signo fue de 86.45 por ciento. La asociación de la variante en la respuesta del Fenómeno, en los pacientes con tumor y en los sujetos sin lesión del S.N.C., fue de alta significancia estadística (p<0.00001). El valor lateralizante de este signo, puede ser muy útil como signo semiológico en el examen clínico rutinario. La ausencia de variantes del Fenómeno de Bell en sujetos sanos pareciera ser más relevante que su anormalidad en pacientes con lesión tumoral del S.N.C.

Farmacologia oftalmologica. Revision bibliografica / Opthalmologic pharmacology. A review of the literature

Se realiza una revision bibliografica de las caracteristicas farmacologicas mas relevantes de algunos medicamentos utilizados en Oftalmologia. De forma general se abarcan particularidades farmacocineticas y farmacodinamicas del ojo. Se hace referencia a quellas drogas que ejercen su accion por medio de las respuestas fisiologicas del ojo a los mecanismos de transmision en las uniones neuroefectoras del Sistema Nervioso Autonomo y que tienen un amplio uso en el diagnostico y tratamiento de afecciones propias de esta area de la Medicina

Red nucleus and eyeblink conditioned response in rabbits

The role of red nucleus [RN] in the acquisition of rabbit eyeblink conditioned response has been a controversial issue. In the present study the effect of an RN lesion and changes in RN electrical activity during eyeblink conditioning have been investigated. Eighteen male albino rabbits, 1.5 to 2 kg in weight, were used. Animals were divided into four groups: The RN lesioned group which received a contralateral RN electrical lesion [2mA, 15 sec], the sham operated group, the electrophysiological group in which recording electrodes were implanted in the contralateral RN, and the intact [control] group. Rabbits received training for classical conditioning of the eyeblink response. A tone was the conditioned stimulus and an airpuff was the unconditioned stimulus. Our data shows that in the RN lesioned group eyeblink conditioned and unconditioned response amplitudes were significantly lower than the control and sham operated groups. Also the percentage of conditioned response incidence was decreased in the lesioned group and the latency of unconditioned response was significantly greater than the other two groups. In the electrophysiological group, RN rhythm was increased during learning. In conclusion it seems that the output of RN is capable of modulating the pathways mediating both conditioned and unconditioned responses

Estudios electrofisiológicos en pacientes glaucomatosos / Electrophysiological studies as glucomatous patients

Se estudió un total de 21 pacientes (42 ojos) con glaucoma crónico simple, todos tonométricamente compensados. Fueron divididos en 2 grupos: el primero (GL-1) con discreta o sin afectación de campo visual y el segundo (GL-II)con severa afectación de éste. Se realizaron estudios clínicos y electrofisiológicos. Estos últimos mostraron diferencias significativas entre ambos grupos. Las variables electrofisiológicas (ERG, PEV) en los que se evidencia una mayor afectación para el segundo grupo fueron: el incremento de la latencia y disminución de la amplitud de las ondas a y b del electrorretinograma (ERG), así como un incremento de la latencia de la onda P2 (P100) del potencial evocado visual (PEV) a patrón. Los resultados fueron comparados con las normas de nuestro laboratorio para estas variables y procesados de acuerdo con el diseño estadístico

Studies on the eye of some nile teleosts III- a comparative study on the histology of the retina of two nile teleostean fishes

In this study, the retinae of two Nile teleostean fishes; a superficial living fish [Gambusia affinis]and a deep living one [Clarias lazera] were examined mainly by light microscopy and found to be duplex i.e. to contain both rods and cones. The different layers of the two retinae were described with particular regard to the visual cell layer. In the retina of Gambusia, the cones predominated over the rods and vice versa in the bottom fish, Clarias lazera. This form of structure formed an adaptation to the habitat of each fish, where Gambusia lived in nearly dark medium near the bottom of the river. Foveal regions were found only in Gambusia and in contrast to mammals, all the layers of the retina were well represented in the foveal regions. In Gambusia, there was only one blind spot because the optic nerve had one exit, while the optic nerve in retina of Clarias exited in about eight to ten points that constitutes eight or ten blind spots in this fish. Retinal blood vessels were more numerous in the inner surface of the retina of Clarias. It was concluded that the foregoing findings pointed to the great efficiency of the retina in Gambusia [which lives in a well illuminated habitat] compared with the retina of Clarias, the bottom living fish

Algunos factores de riesgo que predisponen a la disminucion de agudeza visual en escolares de segundo y tercero de primaria, Concentracion Matilde Anaray / Some risk factors that predispose to diminish of the visual acuty in children from second and third year of primary school, Concentracion Matilde Anaray

Estudio comparativo entre un grupo de 40 ninos con disminucion de la agudeza visual y otro similar en tamano, edad y escolaridad, sin disminucion de la agudeza visual, para identificar los factores de riesgo para alteraciones de la vision. La informacion se recolecto mediante una untrevista estructurada a los padres que permitio identificar signos y sintomas de antecedentes de infeccion ocular, estrabismo, e iluminacion habitual del lugar donde el nino ve television. Para registrar los datos, se empleo un formato previamente disenado que facilito el analisis. El riesgo, se estudio cualitativamente en forma separada y posteriormente se establecieron relaciones de asociacion por razon de disparidad y prueba de significancia. En referencia a infeccion ocular se encontro asociacion con disminucion de la agudeza visual, pero fue mayor entre esta y estrabismo. No se encontro significativo como factor de riesgo el ver television con la luz ambiental apagada. Estos hallazgos revelan la importancia de reforzar los habitos higienicos en la familia y en el nino, y de ensenar a los padres a detectar tempranamente infeccion ocular y estrabismo como estrategias para prevenir la disminucion de la agudeza visual en escolares

Eletrofisiologia ocular: 1 - princípio e objetivos / Ocular electrophysiology: 1 - principles and objectives

O Autor apresenta aspectos relevantes da história e dos princípios básicos da eletofisiologia ocular, define a terminologia usada e situa os objetivos da semiologia eletrofisiológica no conjunto dos exames funcionais da retina

Comportamiento mecanico de la esclerotica "in vivo" / Mechanical behavior of sclerotic coat \"in vivo\"

Se estudiaron una serie de treinta conejos, a los cuales se les indujo deformaciones semejantes a las ocurridas en el polo posterior en casos de miopía avanzada. Estas deformaciones fueron producidas mediante una "copa de succión" especialmente diseñada para tal efecto. Se hizo un análisis sobre la aplicación de las teorías de las "conchas", concluyendo que se pueden utilizar los conocimientos de las "conchas delgadas" en el estudio mecánico de los ojos. Los experimentos básicamente consistieron en la producción de deformaciones controladas a diferentes niveles de presión, estudiándose un amplio rango de incrementos de presión y de tiempos. La conclusión principal fue que la esclera es un tejido cuyo comportamiento es elástico y posee una rata de CREEP (fluencia) moderadamente alta. Estas propiedades del material indican que el ojo se puede reacomodar cuando se somete a presiones inducidas y por lo tanto el glaucoma y la miopía podrían presentarse sin que existan condiciones de alta presión en el ojo

action of glutamate on the spectral absorbance of retina's fish

Perfusion of the isolated retina of the bulti [tilapia nilotica] A with Ringer's solution containing 5 mM glutamate is shown to cause changes in the optical density of the retina. The absorbance spectrum of these changes were recorded every 15 minutes up to 90 minutes after start of perfusion. The results indicate that there were polyphases changes over the spectrum of wavelength ranging from 350 to 650 nm. The maximum increase in optical density was found to be 25 percent at about 420 nm, while the maximum drop was 60 percent at 440-450 nm

Eletrofisiologia ocular: contribuiçäo da eletrofisiologia em crianças com opacidades dos meios transparentes / Ocular electrophysiology: contributions of electrophysiology in children with transparence means opacity

O presente trabalho consta de breve mostra dos conceitos básicos de eletrofisiologia ocular, com referência específica ao ERG e PEV obtidos após fotoestimulaçäo monocromática e apresentaçäo de casos clínicos de crianças com opacidade dos meios transparentes, onde estes exames foram de alguma valia na avaliaçäo do prognóstico visual pré-cirúrgico