ABSTRACT
El objetivo de este estudio es conocer el comportamiento biométrico de las estructuras oculares que participan en la acomodación. Para estudiar los cambios biométricos de las estructuras del segmento anterior del globo ocular, in vivo y durante la acomodación, hemos elegido el ultrasonido de alta frecuencia. Se estudiaron 75 pacientes divididos en 3 grupos, según su rango etario: grupo 1, de 30 a 45 años; grupo 2, de 46 a 60 años, y grupo 3, de 61 a 70 años. Los resultados obtenidos nos muestran cómo varían la forma y la dimensión de las estructuras del segmento anterior y las relaciones entre sí, permitiendo conocer sus comportamientos en la pérdida de la acomodación de los distintos grupos etarios estudiados. Esta técnica permite una evaluación biométrica, morfológica y funcional del segmento anterior, incluyendo la cápsula posterior del cristalino y los cambios del cuerpo ciliar (que no hemos logrado estudiar con otras técnicas). La ultrabiomicroscopía posibilita la visualización durante la acomodación de las cápsulas anterior y posterior del cristalino, la zónula con sus inserciones en la cápsula ecuatorial y el cuerpo ciliar, y la úvea anterior en relación con el cristalino. Las imágenes ultrasónicas obtenidas representan las estructuras del segmento anterior y sus modificaciones in vivo y en tiempo real durante la acomodación. El ultrasonido ha mostrado ser el método diagnóstico más adecuado para esta investigación.(AU)
The aim of this study is to understand the biometric behaviour of the ocular structures involved during accommodation. We chose high-frequency ultrasound to study ocular globe anterior segment structures biometric changes in vivo and during accommodation. This technique allows biometric screening, morphological and functional anterior segment, including the posterior lens capsule and changes of the ciliary body that we have failed to study with other techniques. The ultrabiomicroscopy allows visualization during accommodation of the anterior and posterior capsules of the lens, the zonules with insertions in the equatorial capsule and the ciliary body and anterior uvea relative to the lens. The ultrasound images obtained represent the anterior segment structures and their modifi cations in vivo and in real time during accommodation. We studied 75 patients divided into three groups according to age range: Group 1 from 30 to 45 years, Group 2 of 46-60 years, and Group 3 of 61-70 years. The results obtained show how they vary the shape and size of anterior segment structures and relationships with each other, allowing to know their behavior in the loss of accommodation of different age groups studied Ultrasound has proven to be the most appropriate diagnostic method for this research.(AU)
ABSTRACT
El objetivo de este estudio es conocer el comportamiento biométrico de las estructuras oculares que participan en la acomodación. Para estudiar los cambios biométricos de las estructuras del segmento anterior del globo ocular, in vivo y durante la acomodación, hemos elegido el ultrasonido de alta frecuencia. Se estudiaron 75 pacientes divididos en 3 grupos, según su rango etario: grupo 1, de 30 a 45 años; grupo 2, de 46 a 60 años, y grupo 3, de 61 a 70 años. Los resultados obtenidos nos muestran cómo varían la forma y la dimensión de las estructuras del segmento anterior y las relaciones entre sí, permitiendo conocer sus comportamientos en la pérdida de la acomodación de los distintos grupos etarios estudiados. Esta técnica permite una evaluación biométrica, morfológica y funcional del segmento anterior, incluyendo la cápsula posterior del cristalino y los cambios del cuerpo ciliar (que no hemos logrado estudiar con otras técnicas). La ultrabiomicroscopía posibilita la visualización durante la acomodación de las cápsulas anterior y posterior del cristalino, la zónula con sus inserciones en la cápsula ecuatorial y el cuerpo ciliar, y la úvea anterior en relación con el cristalino. Las imágenes ultrasónicas obtenidas representan las estructuras del segmento anterior y sus modificaciones in vivo y en tiempo real durante la acomodación. El ultrasonido ha mostrado ser el método diagnóstico más adecuado para esta investigación.
The aim of this study is to understand the biometric behaviour of the ocular structures involved during accommodation. We chose high-frequency ultrasound to study ocular globe anterior segment structures biometric changes in vivo and during accommodation.This technique allows biometric screening, morphological and functional anterior segment, including the posterior lens capsule and changes of the ciliary body that we have failed to study with other techniques. The ultrabiomicroscopy allows visualization during accommodation of the anterior and posterior capsules of the lens, the zonules with insertions in the equatorial capsule and the ciliary body and anterior uvea relative to the lens. The ultrasound images obtained represent the anterior segment structures and their modifi cations in vivo and in real time during accommodation.We studied 75 patients divided into three groups according to age range: Group 1 from 30 to 45 years, Group 2 of 46-60 years, and Group 3 of 61-70 years.The results obtained show how they vary the shape and size of anterior segment structures and relationships with each other, allowing to know their behavior in the loss of accommodation of different age groups studiedUltrasound has proven to be the most appropriate diagnostic method for this research.
Subject(s)
Male , Adult , Female , Accommodation, Ocular , Biometry , Diagnosis , Diagnostic Imaging , Eye , Vision, OcularABSTRACT
PURPOSE: To study the presence of hyaluronidase activity in the rabbit trabecular meshwork and its regulation by brimonidine. METHODS: A spectrophotometric assay that consists of the assessment of N-acetylhexosamine groups released from hyaluronic acid was used to examine hyaluronidase activity. Cyclic adenosine monophosphate (cAMP) levels were assessed by radioimmunoassay. RESULTS: Hyaluronidase activity was detected in the rabbit trabecular meshwork. Its optimal activity was in the acid range of pH 3.8. Brimonidine significantly increased trabecular hyaluronidase-specific activity and decreased cAMP accumulation. Yohimbine significantly inhibited the effect of brimonidine on both hyaluronidase activity and cAMP accumulation. CONCLUSIONS: The finding of endogenous hyaluronidase activity in rabbit trabecular meshwork supports the hypothesis that this tissue can metabolize its own glycosaminoglycan (GAG) products. The present results suggest, however, that the hypotensive effect of brimonidine could be mediated, at least in part, by its ability to increase GAG catabolism, probably through a cAMP-independent mechanism.
Subject(s)
Adrenergic alpha-Agonists/pharmacology , Hyaluronoglucosaminidase/metabolism , Quinoxalines/pharmacology , Trabecular Meshwork/drug effects , Adrenergic alpha-Antagonists/pharmacology , Animals , Brimonidine Tartrate , Cyclic AMP/metabolism , Hydrogen-Ion Concentration , Male , Quinoxalines/antagonists & inhibitors , Rabbits , Radioimmunoassay , Trabecular Meshwork/enzymology , Yohimbine/pharmacologyABSTRACT
In eyes treated with corticosteroids the thickness of the trabecula is increased, the width of the intertrabecular spaces reduced and the number of trabecula per surface unit greater. In eyes perfused with hyaluronidase the opposite is seen, i.e., the thickness of the trabecular is reduced, the width of the intertrabecular spaces increased and the number of trabecula per surface unit diminished. The number of glycoproteins in the ground substance increases after treatment with corticosteroids while perfusion with hyaluronidase has the opposite effect. We have treated 27 rabbits, of which 17 with local administration of Dexamethasone 0,1%, 5 with subconjunctival injections and 5 as controls.
Subject(s)
Adrenal Cortex Hormones/pharmacology , Cornea/drug effects , Hyaluronoglucosaminidase/pharmacology , Sclera/drug effects , Trabecular Meshwork/drug effects , Animals , Microscopy, Electron, Scanning , Rabbits , Trabecular Meshwork/ultrastructureABSTRACT
Following perfusion of the anterior chamber with hyaluronidase, a great reduction in the basic substance of the sclero corneal trabeculum as well as increased activity of the goniocytes were observed with the electron microscope. The opening of the trabecular meshes thus produced constitutes a kind of chemical trabeculectomy, attributable to the depolymerization of the hyaluronates of the basic substance by the hyaluronidase of the goniocytes.
