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The lens is located towards the front part of the vertebrate eye, called the anterior segment, which includes the cornea and iris positioned in front of the lens. The lens is held in place by the suspensory ligaments (Zonule of Zinn), [1] attaching the lens at its equator to the rest of the eye [2] [3] through the ciliary body.
The lens is suspended to the ciliary body by the suspensory ligament (zonule of Zinn), made up of hundreds of fine transparent fibers which transmit muscular forces to change the shape of the lens for accommodation (focusing). The vitreous body is a clear substance composed of water and proteins, which give it a jelly-like and sticky composition.
Sheep eye lens capsule with ligaments attached. The capsule is lifting off the lens showing cell fiber ends beneath. Microscope image of lens capsule in relation to lens cell types. The lens capsule is a component of the globe of the eye. [1] It is a clear elastic basement membrane similar in composition to other basement membranes in the body.
Phenotypic convergence of the geometry of cephalopod and most vertebrate eyes creates the impression that the vertebrate eye evolved from an imaging cephalopod eye, but this is not the case, as the reversed roles of their respective ciliary and rhabdomeric opsin classes [36] and different lens crystallins show.
Pages in category "Human eye anatomy" ... Lens (vertebrate anatomy) Levator palpebrae superioris muscle; M. Macula; Medial palpebral ligament; Medial rectus muscle;
What is less well understood is how the subtle, precise and very quick changes in lens shape are made. Direct experimental proof of any lens model is necessarily difficult as the vertebrate lens is transparent and only functions well in the living animals. When considering vertebrates, aspects of all models may play varying roles in lens focus.
Lens development is closely related to optic vesicle development. The interaction between the growing vesicle and the ectoderm causes the ectoderm to thicken at that point. This thickened portion of the ectoderm is called the lens placode. Next, the placode invaginates and forms a pouch referred to as the lens pit.
In children, early diagnosis and treatment of impaired visual system function is an important factor in ensuring that key social, academic and speech/language developmental milestones are met. Cataract is clouding of the lens, which in turn affects vision. Although it may be accompanied by yellowing, clouding and yellowing can occur separately.