Optic chiasm lesions

Introduction to chiasm The optic chiasm is composed of both the retina of the retina and the non-crossing fibers of the retina. The damage of the optic chiasm is clinically more common, but it is rarely caused by its own disease, most of which is caused by the invasion of nearby tissue diseases. Among them, tumor compression is the most common, and it occurs due to different damaged parts. The change in vision also changes frequently. Fundus examination normal value: the normal optic disc of the optic disc is slightly elliptical, reddish, with clear boundaries, the center is funnel-shaped depression, and the color is slightly light, called physiological depression. The central and venous arteries of the retina are bright red, the veins are dark red, and the ratio of arterial to venous diameter is 2:3. The macular part is located at the side of the eyeball 2 to 2.5 PD (the diameter of the optic disc), slightly below, about one disc or slightly larger, no blood vessels, and the center has a large point of reflective point called the central concave light reflection. . basic knowledge Sickness ratio: 0.0001% Susceptible people: no specific population Mode of infection: non-infectious Complications: painful ophthalmoplegia

Causes of chiasm

Adjacent tissue lesions (30%)

The damage of the optic chiasm is clinically more common, but it is rarely caused by its own disease, most of which is caused by the invasion of nearby tissue diseases. Among them, tumor compression is the most common, and it occurs due to different damaged parts. The change in vision also changes frequently.

Optic chiasm prevention

Mostly caused by other lesions, such as tumor compression, so pay attention to the prevention of primary disease. A reasonable diet can take more high-fiber and fresh vegetables and fruits, balanced nutrition, including essential nutrients such as protein, sugar, fat, vitamins, trace elements and dietary fiber, with a combination of vegetarian and vegetarian foods. The complementary role of nutrients in food is also helpful in preventing this disease.

Optic chiasm Complications, painful ophthalmoplegia

Defects in visual field, blind spots around the center or near the center, blind spots at the center, decreased visual acuity, and narrow vision. The defect of the field of view means that when looking at things, the field of view is incomplete, as if there is any shadow blocking the line of sight, sometimes a corner is completely dark, and nothing can be seen. Visual field defect is a condition of the disease, which may indicate that the patient has a certain disease, and the disease with visual field defect is a serious disease of the ophthalmology. Each person feels different from the visual field defect, some are slight, some are serious, and the degree is different. Very big.

Symptoms of chiasmosis common symptoms blunt blind visual field defect internal hemorrhage posterior optic neuritis optic atrophy symmetry

(1) Vision loss: It is an early symptom of optic chiasm, often coexisting with headache. This type of patient first visits ophthalmology. The general visual acuity is gradually decreased, but there are also rapid decline. The latter is more common in cystic tumors and intratumoral hemorrhage. It is often misdiagnosed as acute retrobulbar optic neuritis, so it should be combined with visual field and systemic conditions for differential diagnosis.

(B) visual field changes: the bilateral half-field defect of the bilateral eye, called bilateral hemianopia, is one of the important signs of damage in the middle of the optic chiasm, but because the optic nerve fibers are arranged in the optic chiasm The position above is not constant, and the opticized compression site often changes, so that the visual field defects appearing are not completely consistent. For example, the optic chiasm at the beginning of the optic tract can occur in the same direction, that is, the ipsilateral half field Defects, such as the involvement of the front of the optic chiasm, tend to be more than one side of the lesion, forming a blind all-eye, and the other side of the eye is hemianopia.

(C) ophthalmopathy: parasagittal lesions or saddle tumors to the saddle development, can involve eye movements, trochlear and abduction of cranial nerves, eye movement disorders.

(4) Pupil change: When there is a certain vision in both eyes, the pupil responds to the light normally or weakly. If one eye is completely blind, the pupil of the eye directly loses its light response.

Examination of chiasm

Fundus examination is an important method to examine the vitreous, retina, choroid, and optic nerve diseases.

Fundus examination normal value: the normal optic disc of the optic disc is slightly elliptical, reddish, with clear boundaries, the center is funnel-shaped depression, and the color is slightly light, called physiological depression. The central and venous arteries of the retina are bright red, the veins are dark red, and the ratio of arterial to venous diameter is 2:3. The macular part is located at the side of the eyeball 2 to 2.5 PD (the diameter of the optic disc), slightly below, about one disc or slightly larger, no blood vessels, and the center has a large point of reflective point called the central concave light reflection. .

Diagnostic diagnosis of chiasm

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

1. Visual field change: Optic nerve fibers from both eyes occupy a certain position in the optic tract, and are not completely mixed. Therefore, when one side of the visual beam is damaged, the optic nerve fiber is often more affected than the other eye. Complete (non-overlapping) co-directional hemianopia (ie, the nature, extent, size, and speed of the ipsilateral half-field defect in both eyes) and macular division are one of the characteristics of visual beam damage.

2. Fundus changes: early fundus is normal, usually three months later, the eyes of the two-eye optic disc can appear pale, such as the right eye bundle damage, there will be right eye optic disc and half of the left eye optic disc nasal half pale , is the second characteristic of the optical beam damage.

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