11/17/2023 0 Comments Ectopic pupil definition![]() ![]() The point where the sclera and cornea are continuous is the sclerocorneal junction or the limbus. The cornea owes its transparent clarity to both the structural arrangement of the collagen and its constant, relatively dehydrated state 1. The sclera makes up the posterior 5/6 of the fibrous layer and provides structure and protection to the globe, as well as serving as a point of insertion to the extraocular muscles. The cornea makes up the protruding anterior 1/6 of the fibrous layer. The fibrous layer of the globe is made up of the opaque sclera and the transparent cornea. The fundus of the globe refers to the retina, optic disc, macula and fovea collectively, and hence funduscopy/fundoscopy (alternative spellings: both acceptable). Both of these substances allow diffusion of nutrients to adjacent structures and act to maintain the shape of the globe. This trilaminar structure brings about a further subdivision of the eye into two major segments the anterior segment, which contains aqueous humor, and the posterior segment, which contains the gel-like vitreous humor. ![]() ![]() The surface of the globe is made up of three layers, the outermost fibrous layer, the intermediate vascular layer, and the innermost neural layer. Importantly, both myopia and hypermetropia can change the axial diameter substantially: down to ~20 mm in hypermetropia and up to ~26 mm in myopia 10. Very similar measurements can be obtained with MRI or dedicated ophthalmic instruments 11. SizeĮach globe is an approximately spherical structure with relatively constant size in adults with normal eyesight, and does change with age nor does it vary with sex or boy size 2,10,11.Ī normal adult emmetropic eye measures (by CT, sclera to sclera) 10: The globe is suspended by the bulbar sheath in the anterior third of the bony orbit. ![]()
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