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These diverticula make their appearance before the closure of the anterior end of the neural tube; [1] [2] after the closure of the tube around the 4th week of development, they are known as the optic vesicles. Previous studies of optic vesicles suggest that the surrounding extraocular tissues – the surface ectoderm and extraocular mesenchyme ...
Failure of the cells of the posterior portion of the optic vesicles to express growth hormone affects the differentiation of other cells of the eye. The choroid, especially lateral to the optic disc, is hypoplastic (underdeveloped). A coloboma, or hole, may form in or near the optic disc due to a failed closure of embryonic tissue.
The optic vesicles project toward the sides of the head, and the peripheral part of each expands to form a hollow bulb, while the proximal part remains narrow and constitutes the optic stalk. [1] [2] Closure of the choroidal fissure in the optic stalk occurs during the seventh week of development. The former optic stalk is then called the optic ...
The optic vesicles then develop into the optic cup with the inner layer forming the retina and the outer portion forming the retinal pigment epithelium. The middle portion of the optic cup develops into the ciliary body and iris. [7] During the invagination of the optic cup, the ectoderm begins to thicken and form the lens placode, which ...
General health G(M)P: General (medical) practitioner HA: Headaches HARC: Harmonious abnormal retinal correspondence HM: Hand motion vision – state distance Hx: History IOL: Intra-ocular lens IOP: Intra-ocular pressure ISNT: Inferior, Superior, Nasal, Temporal rule used to assess optic disc appearance K: Keratometry OS oculus sinister (left ...
Animal-assisted therapy is an alternative or complementary type of therapy that includes the use of animals in a treatment. [4] [5] It falls under the realm of animal-assisted intervention, which encompasses any intervention in the studio that includes an animal in a therapeutic context such as emotional support animals, service animals trained to assist with daily activities, and animal ...
During embryonic development of the eye, the outer wall of the bulb of the optic vesicles becomes thickened and invaginated, and the bulb is thus converted into a cup, the optic cup (or ophthalmic cup), consisting of two strata of cells.
It is crucial in determining the health of the retina, optic disc, and vitreous humor. [citation needed] The pupil is a hole through which the eye's interior can be viewed. For better viewing, the pupil can be opened wider (dilated; mydriasis) before ophthalmoscopy using medicated eye drops (dilated fundus examination).