Myopia arc

Introduction Since the posterior part of the wall of the high myopia is protruding backward, the optic nerve enters the ball obliquely. The side of the optic papilla (mostly the temporal side) is displaced backwards, so that the optic papilla loses its normal vertical elliptical shape under the ophthalmoscope and becomes significantly vertical (or lateral, oblique (oval, even like a braid) There is a crescent spot called the conus, or the extensive conus. It is the most common fundus change in myopia. The smallest is not easy to see. Out, the big can reach the size of the disc. Some surround the optic disc, and even reach the macular area.

Cause

1. The extension of the posterior pole of the eyeball, mainly on the temporal side of the nipple, allows the scleral and optic nerves of the optic nerve to extend to the temporal side as a skewed cylinder, so that part of the wall can be seen by the ophthalmoscope. Most notably, the pure white sclera is exposed, and choroidal vascular residuals and a small amount of pigmentation are sometimes seen at the junction with the retina.

2. In the eyeball extension of myopia, the pigment epithelial layer of the retina is pulled away from the edge of the nipple, exposing the choroidal blood vessels that are not covered by the pigment epithelial layer. The exposed choroid can leave the optic nerve head, expose the posterior sclera, or atrophy. The remnant tissue after atrophy covers the sclera, thus forming arcuate regions of different sizes, yellow and white phases and residual pigments.

an examination

Related inspection

Eye function examination ophthalmology examination ophthalmoscopy

Through the observation of the optic disc nearsightedness arc, it can be distinguished whether myopia is axial or refractive myopia, and can make a preliminary judgment and evaluation on the refractive power of axial myopia, which is used as an examination method before dilated optometry. Certain clinical significance can be regarded as an objective and simple examination method. Recently, the use of fundus stereo photography and computer image processing to study the changes in myopia arc, the width of myopia arc is significantly related to myopia. Therefore, further research on the changes of myopia arc with new technology may be helpful for evaluating the development and differential diagnosis of myopia.

Differential diagnosis

High myopia macular degeneration is based on a history of high myopia, typical leopard-like in the fundus, typical degenerative changes in optic disc myopia and macular, and diagnosis is not difficult. But sometimes it is different from ocular toxoplasmosis, especially in stationary or congenital. Although ocular toxoplasmosis is a uveitis, it often has no anterior inflammation, only the posterior uveal lesions, and the predilection site is also located in the posterior pole. In the quiescent phase or congenital, it can only show the atrophy of the macular area. Round lesions may be accompanied by hyperpigmentation, similar to atrophic lesions of high myopia. However, patients with toxoplasmosis have a history of contact with animals such as cats and dogs, and can be proved by skin experiments and serological tests. Finally, diagnostic treatment is also available. Ocular toxoplasmosis can be significantly effective in combination with sulfonamide, minocycline, and clindamycin in combination with hormone therapy.

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