نتایج جستجو برای: optic lens
تعداد نتایج: 94610 فیلتر نتایج به سال:
A crucial step in eye organogenesis is the transition of the optic vesicle into the optic cup. Several transcription factors and extracellular signals mediate this transition, but whether a single factor links them into a common genetic network is unclear. Here, we provide evidence that the LIM homeobox gene Lhx2, which is expressed in the optic neuroepithelium, fulfils such a role. In Lhx2(-/-...
Aim: To design an accommodating intraocular lens with extended accommodative range that can be adapted to current standard phacoemulsification and endocapsular implantation technique. Method: Ray tracing analysis and lens design; cadaver eye implantation. Results: Ray tracing analysis indicated that axial movement of an exaggerated converging anterior optic linked by spring loaded haptics to a ...
Early studies on lens induction suggested that the optic vesicle, the precursor of the retina, was the primary inducer of the lens; however, more recent experiments with amphibians establish an important role for earlier inductive interactions between anterior neural plate and adjacent presumptive lens ectoderm in lens formation. We report here experiments assessing key inductive interactions i...
The physical contact of optic vesicle with head surface ectoderm is an initial event triggering eye morphogenesis. This interaction leads to lens specification followed by coordinated invagination of the lens placode and optic vesicle, resulting in formation of the lens, retina and retinal pigmented epithelium. Although the role of Pax6 in early lens development has been well documented, its ro...
PURPOSE Wnt2b is normally expressed at the optic cup lip and is implicated in ciliary body induction. The lens has often been considered an organizer for the anterior eye, but recent studies demonstrate that the anterior cell fates are correctly specified in the absence of the lens. This study uses Wnt2b as a marker to reveal the mechanism behind the specification of the anterior domain of the ...
PURPOSE To design and develop an accommodating intraocular lens (IOL) for endocapsular fixation with extended accommodative range that can be adapted to current standard extracapsular phacoemulsification technique. METHODS Ray tracing analysis and lens design; finite element modeling of biomechanical properties; cadaver eye implantation; initial clinical evaluation. RESULTS Ray tracing anal...
Vertebrate lens development is a classical model system for studying embryonic tissue interactions. Little is known, however, about the molecules mediating such inductive events. Here, we show that Bmp4, which is expressed strongly in the optic vesicle and weakly in the surrounding mesenchyme and surface ectoderm, has crucial roles during lens induction. In Bmp4(tm1) homozygous null mutant embr...
We used the teleost Astyanax mexicanus to examine the role of the lens in optic nerve and tectum development. This species is unusually suited for studies of nervous system development and evolution because of its two extant forms: an eyed surface dwelling (surface fi sh) and several blind cave dwelling (cavefi sh) forms. Cavefi sh embryos initially form eye primordia, but the lens eventually d...
this study was conducted to determine the use of three-dimensional ultrasonography (3du) in ocular imaging of the dog and measuring of its optical axis. 12 healthy mixed-breed dogs including 6 males and 6 females were studied. 3du of the eyes were done using a 5–12 mhz linear trapezoid transducer. 3du of the eyes were evaluated and the normal optical long axis through a line between the cornea ...
PURPOSE To describe the clinical and pathological features of a case of hydrogel intraocular lens (IOL) calcification. CASE REPORT A 48-year-old man underwent explantation of a single-piece hydrophilic acrylic intraocular lens in his left eye because of decreased visual acuity and milky white opalescence of the IOL. The opacified lens was exchanged uneventfully with a hydrophobic acrylic IOL....
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید