According to the degree of myopia, ametropia with myopia degree greater than 600 degrees (children > 400 degrees) is called high myopia. Because this kind of myopia has pathological changes in the eyes, high myopia is equated with pathological myopia or degenerative myopia. The cause of high myopia is still unknown. Pathological myopia occurs in a large genetic relationship. The acquired environment plays an important role in the onset of myopia. Recommended reading: High myopia? Be careful when exercising!In order to open the market, fashion eyeglasses Constantly improve the ability of business development and create an extraordinary brand image for it. https://dillydollaroptical.com/
1 pathophysiology
Longer axial length is the pathological and anatomical basis of myopia. The main lesion is at the back of the eyeball, which is pear-shaped or egg-shaped.
(1) The corneal posterior elastic layer may rupture in high myopia.
(2) Scleral thinning in scleral myopia is one of the pathological features. The longitudinal fibers become thinner and the transverse fibers separate or disappear. This is related to abnormal collagen in sclera.
(3) The ciliary body mainly shows atrophy, which can be confined to annular fibers.
(4) Due to degeneration and liquefaction of vitreous body, the normal grid structure is destroyed, and gray fibers and vacuoles increase. Adhesion can occur at the periphery.
High myopia is not suitable for long-term reading.
(5) The main changes of choroid are progressive atrophy and thinning of choroid, including degeneration, destruction of melanocytes and the appearance of new blood vessels. The elastic layer cracked, showing paint cracks.
(6) The optic disc is pulled back by the eyeball, and the choroid around the optic disc is detached from the optic disc. Bruch The membrane also ends here, and the sclera is exposed in the absence of the outer retina and pigment epithelium, thus forming a white arc spot.
(7) The main manifestation of retina is degeneration. Include atrophy and degeneration. The normal hexagonal arrangement of retinal pigment epithelial cells was replaced by irregular cell layers. There are many pigments outside the cell. Bruch Pigment proliferates and accumulates at the membrane split. Annular Fuchs spots can be formed in macular area. The absence of elastic layer makes retina-choroid fuse together, and finally scar and pigment appear. Choroidal neovascularization can penetrate Bruch membrane rupture and grow under retina, forming subretinal neovascularization membrane. Macular hemorrhage caused by rupture of new blood vessels. Vitreous body can attach and traction atrophic retina. Can cause retinal breaks and detachment.