Optic disc tilt

Introduction Degenerative myopia has optic disc tilt and myopic arc performance. 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 disc (mostly the temporal side) is displaced backwards, causing the disc to lose its normal slightly elliptical shape under the ophthalmoscope, resulting in a pronounced vertical (or lateral, oblique) elliptical shape, even like a braid. There is a crescent spot at the junction with the rearward displaced side, called the conus, or the extensive conus. The near-axial arc is slightly brown, the boundary is blurred, and the upward traction arc (supertraction conus). The inner side of the stretch myopia arc is white, which is exposed to the sclera, and the outer side is light brown, which is caused by the disappearance of the pigment epithelial layer and the exposure of the choroid. The outer boundary of the myopic arc is clear, but it is often connected with the atrophy area of the posterior pole. The myopic arc is located on the temporal side of the optic disc in most cases, and is also located above or below the iliac crest. More rarely, it is located on the nasal side or the lower side. The former is called the inversive conus; the latter is called the Fuchsconus. When the temporal myopia arc extends outward, upward, and downward, it can surround the entire optic disc, which is the circum papillary chorioretinal atrophy around the optic disc.

Cause

(1) Causes of the disease

Genetics has been identified as a major factor. Its genetic pattern is autosomal recessive, also dominant and X-linked, and highly genetically heterogeneous. In addition to heredity, the acquired environment such as general health, living environment, personal habits, long-term use of close eye work, etc., can contribute to the deepening of myopia.

(two) pathogenesis

The pathogenesis of this disease is extremely complicated. Scleral extension, especially posterior scleral extension and thinning, is the key to the development of axial myopia to high myopia, and is also the pathological basis of degenerative myopia. The reason why the sclera is extended is that there are two different theories, mechanical and biological. In the recent research, some people think that it is caused by one or some genetic mutations, which leads to the abnormal synthesis of scleral collagen. The cause of degeneration of the fundus is also inconclusive. From the available data, it is likely that the early retinal senescence and choroidal dysfunction are caused by the excessive extension and thinning of the sclera.

an examination

Related inspection

Eye and sacral area CT examination of vision

Vision loss, can not be satisfied with correction. The cause of vision loss is extensive atrophy of the retinal neuroepithelial layer. Macular hemorrhage can cause further damage to vision. After the formation of Fuchs plaques and macular atrophy, the irreversibility of vision is deteriorated. The liquefaction of the vitreous turbidity produces a mosquito. When the vitreous body is incompletely detached, a flashing sensation may occur due to traction of the retina in the incomplete detachment.

1. Tigroid fundus: The entire fundus is slightly dark gray, and the choroid is diffusely atrophied. The blood vessels in the capillary layer and the middle vascular layer are reduced or disappeared. The blood vessels in the orange-red vascular layer are exposed, making the fundus a leopard. Skin sample.

2. Optic disc tilt and myopic arc: Since the posterior part of the high myopia wall protrudes backward, the optic nerve enters the ball obliquely. The side of the optic disc (mostly the temporal side) is displaced backwards, causing the disc to lose its normal slightly elliptical shape under the ophthalmoscope, resulting in a pronounced vertical (or lateral, oblique) elliptical shape, even like a braid. There is a crescent spot at the junction with the rearward displaced side, called the conus, or the extensive conus. The near-axial arc is slightly brown, the boundary is blurred, and the upward traction arc (supertraction conus). The inner side of the stretch myopia arc is white, which is exposed to the sclera, and the outer side is light brown, which is caused by the disappearance of the pigment epithelial layer and the exposure of the choroid. The outer boundary of the myopic arc is clear, but it is often connected with the atrophy area of the posterior pole. The myopic arc is located on the temporal side of the optic disc in most cases, and is also located above or below the iliac crest. More rarely, it is located on the nasal side or the lower side. The former is called the inversive conus; the latter is called the Fuchsconus. When the temporal myopia arc extends outward, upward, and downward, it can surround the entire optic disc, which is the circum papillary chorioretinal atrophy around the optic disc.

3. Macular hemorrhage and Fuchs plaque: Macular hemorrhage is bleeding of the choroid (new blood vessels or no neovascularization). Dark red, generally round, size and quantity are uncertain. More common in the macula or near the retinal blood vessels. Repeated bleeding at the same location can cause hyperpigmentation and lead to the formation of Fuchs plaques.

Typical Fuchs are round or oval in shape, with a clear boundary and a slight uplift. The size is 0.3 to 1 PD, black, and sometimes bleeding is visible at the edge of the dark spot. During the course of the lesion, the dark spots can be enlarged or reduced, the shape and color can be changed, and even decomposed into scattered pigment spots, but will not completely disappear.

Fuchs are seen in one or both eyes, and occasionally two dark spots are seen in the fundus.

4. Posterior pole atrophy and lacquer crack-like damage: Choroidal retinal atrophy is white or yellowish white. Round or map shape. Size and quantity vary, isolated or merged into large pieces. Large patches of atrophy can be atrophied around the optic disc and become a large atrophy zone including the optic disc and the macula. Pigmentation often occurs in the atrophic plaque or at its edges, and residual choroidal vessels are sometimes seen. Macular atrophy and its vicinity, often seen branch or reticular white or yellow-white lines, lines similar to angioid streaks in the fundus, wide and narrow, uneven edges or jagged, similar to the old Lacquer cracks, so called lacquer crack lesions.

The lacquer crack-like damage occurs between the macula and the optic disc to the macula, which is caused by the atrophy of the pigment epithelium at the Bruch membrane, and the FFA is transparent.

5. Macular cystic degeneration and macular hole: Under the ophthalmoscope, the macula can be seen with a clear circular erythema with a diameter of 1/3 to 1/2 PD. The retina adjacent to the erythema is slightly grayish, and if there is a limitation, there is a reflective circle around it. Under the slit lamp microscope, if it is cystic degeneration, the light cut surface has a thin front wall tangential line; if it is a split hole, the line is interrupted. The tangential line of the outer wall of the hole is misaligned with the tangential line of the surrounding retina.

6. Posterior scleral staphyloma: The sclera is overextended in the posterior segment of the eyeball, and localized expansion can occur in the posterior pole to form posterior staphyloma. After the ophthalmoscope, the grape swollen like a dish or a crater-like depression, the edge may be slope-shaped, or steeply steep, and the retinal blood vessels are bent and crawled at the edges. The diopter at the bottom of the posterior grape edema is quite different from that at the edge. This difference in diopter is an important basis for the diagnosis of staphyloma.

7. Peripheral retinal cystic degeneration and lattice-like degeneration: common in the vicinity of the serrated edge, fully expanded after binocular indirect ophthalmoscope or three-sided mirror examination is easier to find. The cystic degeneration is round or round red. Under the background of the retinal gray-white atrophy lesion, the realm is clear. Around the atrophic lesion, there is also a white line formed by the whitening of the small blood vessels of the retinal tip, which is called a lattice degeneration. The cystic degeneration ruptures and forms a retinal tear.

8. Vitreous liquefaction turbidity: The vitreous gel is depolymerized and liquefied, and some parts are concentrated into an off-white membrane or a cord-like turbidity. Under the slit light microscope section inspection, the turbidity floated in the vitreous cavity. Liquefaction of the vitreous can cause the vitreous to detach before and after, and it is more common to detach later.

According to the development process of myopia and the degree of myopia, it is not difficult to diagnose according to the typical changes of the fundus.

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.

In the elderly, high myopia macular degeneration is associated with choroidal neovascularization of the body scar, to identify with age-related macular degeneration. In general, the choroidal neovascular membrane is small and nearly central, while the latter is often accompanied by fundus arteriosclerosis or hypertensive changes. In addition to discoid scars, there may be changes in early senile discoid lesions, such as single or fused drusen, pigmented epithelial serous or hemorrhagic detachment.

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