Ischemic optic neuropathy

Introduction to ischemic optic neuropathy Ischemic optic neuropathy (ischemicoptico-neuropathy) refers to an acute dystrophic disease of the vascular circulatory disorder of the optic nerve. In the past, this disease was often misdiagnosed as an intracranial tumor or optic discitis, usually with the central retinal artery behind the ball. 9 ~ 11mm into the optic nerve is the boundary, clinically divided into two types of anterior segment and posterior ischemic optic neuropathy. It is the most common cause of optic disc edema in people over 50 years of age. basic knowledge The proportion of illness: 0.005% Susceptible people: more common in the elderly Mode of infection: non-infectious Complications: optic nerve head edema and optic disc edema

Causes of ischemic optic neuropathy

More common in the elderly, over 60 years old, the age of domestic onset is earlier than that of foreign countries, women are more common than men, single or both eyes have been ill, any systemic disease or eye disease that can make the optic disc insufficient blood supply can cause this disease, systemic disease Such as hypertension, arteriosclerosis, temporal arteritis, carotid artery occlusion, diabetes, leukemia and polycythemia, etc., low or too high intraocular pressure can cause imbalance between the perfusion pressure of the small vessel of the optic disc and the intraocular pressure, due to blood The change of the middle component and the increase of the blood viscosity increase, so that the blood circulation is slow, and the oxygen carrying capacity is reduced, resulting in the lack of oxygen in the optic disc.

(1) Causes of the disease

Ischemic optic neuropathy is divided into arteritic anterior ischemic optic neuropathy (arteritic AION) and non-arteritic anterior ischemic optic neuropathy (nonarteritic AION): the former is composed of giant cell blood vessels. Caused by inflammation, the patient's age is too large, often accompanied by inflammation of large blood vessels such as temporal arteritis, mostly in the eyes of both eyes, visual impairment is more serious; non-arteritic patients are younger than the former, about half of the patients with With high blood pressure, 25% of patients have diabetes; about 25% of patients have bilateral eyes.

There are many causes of ischemic optic neuropathy, and the possible causes are:

1. Hemorrhagic shock caused by acute hemorrhage: the blood pressure is too low, so that the blood supply to the small blood vessels on the optic disc is insufficient, blood circulation disorder occurs, and infarction occurs, and local tissue is hypoxic.

2. Hypertension, arteriosclerosis, diabetes, iliac arteritis and other vascular diseases: changes in the blood vessel wall, stenosis or occlusion of the blood vessels, the small blood vessels of the optic disc also change, causing ischemia.

3. Severe anemia: Reduce blood oxygenation; increase blood viscosity, such as polycythemia, leukemia, etc. due to slow blood circulation, resulting in hypoxia of the optic disc.

4. Increased intraocular pressure in glaucoma: the small blood vessels of the optic disc are compressed, causing poor blood flow and insufficient blood supply.

5. Vasculitis: giant cell arteritis, nodular polyarteritis, systemic lupus erythematosus, Buergers disease, allergic vasculitis, post-viral vasculitis, vaccination, syphilis, radiation necrosis.

6. Systemic vascular disease: hypertension, atherosclerosis, diabetes, migraine, arteritis, carotid artery obstructive disease.

7. Blood diseases: polycythemia vera, sickle cell disease, acute hypotension (shock), G-6-PD deficiency.

In addition, there are some eyelids and local inflammation of the eyeball, which may also cause the disease.

(two) pathogenesis

According to recent studies, the pathogenesis of this disease is due to the ischemic lesions in the small blood vessels supplying the optic disc, resulting in infarction caused by insufficient local blood supply to the optic disc. According to the pathological anatomy and fluorescein angiography data, the front end of the optic disc is The blood source in the anterior region of the sieve plate and the sieve plate region is supplied by small branches of the posterior ciliary blood vessels, each of which supplies a small portion of the optic disc, and if one or several of the ischemic lesions are present, the branch supplies The optic nerve fibers produce a series of pathological changes such as infarction due to insufficient blood supply, resulting in ischemic optic neuropathy, which can eventually develop into optic atrophy. Some studies have found that the central retinal artery diameter in ischemic optic neuropathy with optic atrophy is higher than other The cause of optic atrophy is 17% to 24%.

Generally speaking, the anatomical structure and blood vessel arrangement of each eye are generally consistent. Therefore, the two eyes often have a history of disease, and the lesions are often very similar. Therefore, the visual field defects of both eyes are more symmetrical.

Ischemic optic neuropathy prevention

1. The disease occurs quickly, impairing visual acuity, and early treatment is important for preventing healthy eyes.

2. To treat this disease, you must have enough knowledge to integrate the systemic disease and adjust the treatment plan appropriately.

3. The visual field needs to be reviewed regularly.

Ischemic optic neuropathy complications Complications optic nerve head edema and optic disc edema

Often combined with systemic blood vascular disease, visible papilledema.

Symptoms of ischemic optic neuropathy Common symptoms Blind spot hemianopia Low blood pressure Hypertension Eye pain Changes in the cornea reflexes secondary optic atrophy Single eye suddenly appears... Visual impairment

The clinical features of ischemic optic neuropathy are:

1. Age of onset: generally more after middle age.

2. The incidence of both eyes: usually multiple eyes or simultaneous onset, the two eyes can be separated by weeks to years, even if there are more than 10 years apart, there is little recurrence.

3. Sudden onset: The general incidence is sudden, and the patient can often clearly indicate the date of onset.

4. Main symptoms: visual dysfunction that is sudden in one or both eyes, and gradually worsens in the next few days or weeks.

5. Rare symptoms: Patients rarely have eyeball pain or pain when the eyeball turns.

6. Fundus examination: The optic disc is mostly small, the physiological depression is not obvious, and the cup/disc is relatively small.

7. The macula area: usually not damaged, so the central visual impairment is sometimes not very heavy.

8. Fundus manifestations of mild optic disc edema: the border is more blurred, the optic disc can have localized color fade areas, there may be some localized flaming hemorrhage around the optic disc, retinal vascular changes are not very obvious, a few retinal arteries are slightly thin, in Some patients with monocular seizures can also observe that the contralateral eye has normal visual function, but it may also manifest as optic disc edema, which may worsen edema and visual function decline soon.

9. After the optic disc edema subsides: the boundary is still very clear, but a certain area of the optic disc may be slightly lighter or paler, sometimes manifested as optic disc edema, and the other optic nerve atrophy, which is often misdiagnosed as Foster-Kennedy syndrome .

10. Visual field defect: It is special. If you carefully examine the peripheral and central visual fields, you can often find its typical visual field changes.

11. Concomitant diseases: Many patients are associated with high blood pressure, diabetes, arteriosclerosis, migraine or sputum arteritis.

12. Measurement of ocular arterial blood pressure: no obvious abnormalities, indicating that the ophthalmic artery and central retinal artery are not ischemic.

13. Arteritic inflammatory AION often has inflammation of the aorta or middle arteries in other parts of the body, such as kidney, liver, mesenteric vessels, coronary arteries, etc.; the iliac artery is thickened under the skin of the ankle, and the iliac artery often has tenderness. The arterial pulsation weakens or disappears.

14. Arterial inflammatory AION patients have significantly increased erythrocyte sedimentation rate and decreased hematocrit, and may be associated with significant anemia.

Although the fundus changes of ischemic optic neuropathy have certain characteristics, such as the optic disc, although there is obvious edema, but not very congested, the retinal blood vessels have no obvious abnormalities and other characteristics, but it is difficult to clearly determine whether it is by the examination of ophthalmoscope alone. Optic discitis is also optic disc edema or ischemic optic neuropathy.

Examination of ischemic optic neuropathy

1. Blood test: erythrocyte sedimentation rate and blood routine examination, to exclude the necessary laboratory tests for other systemic diseases.

2. Radial artery biopsy: suspected arteritis AION, if necessary, should be performed for radial artery biopsy, typical histological changes for granulomatous inflammation of the vessel wall, the three layers of the arterial wall are involved, the intima and middle layer are more Obviously, epithelial-like macrophages, lymphocytes and multinucleated giant cells infiltrate.

3. Plane perimetry: It is common to see that the physiological blind spot is connected to the defect of the surrounding visual field through an arc-shaped defect area. This is also different from the damage of the visual path, indicating that the disease is indeed a nerve fiber bundle starting from the optic disc. got damage.

4. Because the lesion rarely affects the macular bundle fiber of the nipple, the central dark spot is usually not found on the flat visual field meter, and the defect of the visual field mostly bypasses the central gaze area. The visual center of the disease center generally has no major obstacles. The general optic neuritis is different.

In addition, the diagnosis of ischemic optic neuropathy should also be combined with the history of hypertension, arteriosclerosis, diabetes, migraine and other related diseases and related symptoms and signs.

5. Fundus fluorescein angiography: It has certain diagnostic value for ischemic optic neuropathy. In the early stage of angiography, some parts of the optic disc show weak fluorescence, while other parts of the optic disc show normal fluorescence. In the late angiography, this weak fluorescence area has obvious fluorescence. It leaks and shows strong fluorescence. This area corresponds to the part of the visual field defect. A few patients may have local strong fluorescence even in the early stage of angiography, and the fluorescence in the late stage is stronger. However, the early performance is weak. Fluorescence or strong fluorescence, the fluorescence of the obstruction zone and the unobstructed zone of the optic disc is strong and weak, and there is still obvious asymmetry. This asymmetry combined with the defect of the visual field is still helpful for the diagnosis of this disease, advanced ischemia. In cases of sexual optic neuropathy, the optic disc appears atrophic area, which has been weakly fluorescent during the imaging process, indicating that the optic nerve has atrophy.

6. Systemic examination: CT scan of the head, blood test.

Diagnosis and diagnosis of ischemic optic neuropathy

diagnosis:

The most important means of diagnosing ischemic optic neuropathy is visual field examination. The visual field changes of this patient often have some common features, and the surrounding visual field and central plane visual field should be examined very carefully.

1. Peripheral visual field defect of ischemic optic neuropathy

Unlike the visual path damage, the extremely negligible hemianopia or quadrant blindness is bounded by the midline. The defect of the visual field is often large enough to occupy one quadrant or even more than half of the field of view, but horizontal hemianopia and vertical hemianopia. However, the defect area is never bounded by the midline.

2. Plane perimeter inspection

It is common to see that the physiological blind spot is connected to the defect of the surrounding visual field through an arc-shaped defect area, which is also different from the damage of the visual path, indicating that the disease is indeed damaged by the nerve fiber bundle from the optic disc.

Where the age is greater than 40 years old, the visual acuity suddenly drops, and the visual field defect is not tangent, the possibility of ischemic optic neuropathy should be considered, but the optic neuropathy, demyelinating disease and hereditary diseases must be excluded.

The diagnosis of anterior ischemic optic neuropathy can be based on: 1 sudden drop in visual acuity, typical visual field defect; 2 headache, eye marks, especially due to iliac arteritis; 3 optic disc edema; 4 fundus fluorescein angiography showing optic disc low fluorescence or fluorescence Filling slowly or not filling; 5 Raynaud phenomenon in the hands and feet; 6 eyeball compression test has a significant rate of intraocular pressure recovery.

The diagnosis of posterior ischemic optic neuropathy can be based on: 1 sudden decrease in visual acuity and visual field defect; 2 no headache, eye pain; 3 normal fundus or slight nasal side of the optic disc, clear border; 4 age greater than 40 years old, often with hypertension , hypotension, arteriosclerosis or changes in blood composition; Raynaud phenomenon is less than 40 years old, or history of trauma or panic.

It should be pointed out that clinical diagnosis of posterior ischemic optic neuropathy is often difficult, and most of them are presumed to be difficult to distinguish from posterior optic neuritis. There are operational references such as abnormal ocular flow patterns or confirmed cerebral infarction in head CT. Generally, the visual acuity is not heavy. For example, those caused by iliac arteritis are heavier or even have no light sensation. The incidence is sudden. The early optic disc is slightly reddened by light, which is caused by the expansion of the capillaries on the surface of the disc. Limited to a certain quadrant of the optic disc, consistent with visual field defects, rare on both sides, a small amount of nerve fiber layer bleeding around the optic disc, self-resolved within 1 to 2 weeks, flocculous exudate is also visible, 1 to 2 months After optic atrophy, it may be cup-shaped, such as glaucoma optic atrophy, secondary to giant cell arteritis or arteriosclerosis, retinal blood vessels are generally normal, and those with hypertension or arteriosclerosis may have retinal arteriosclerosis changes, if both eyes The disease occurred successively, that is, the optic nerve atrophy caused by optic disc edema, and the optic disc edema occurred in the other eye. The whole Föster-Kennedy comprehensive film was obtained by immunization. Due to the internal tumor, because the posterior ciliary artery branch supplies the optic disc in a zonal manner, the visual field defect of the disease often has a short bundle of dark spots connected with the physiological blind spot, which means that the damaged optic nerve starts from the optic disc, and the general visual path The lesion is blind or blunt, and it is not connected with the physiological blind spot. The above dark spots can be stretched to appear alongside a large piece of God's defect, mostly occurring below or below the visual field of the nose, generally occupying a "quadrant", or sequentially or simultaneously. It occurs in several quadrants, horizontal and vertical, semi-blind, and quadrant blind, but its change is not bounded by horizontal and vertical. Therefore, it is different from the upper quadrant of the visual field. The quadrant is blind or hemian blind, and the visual field defect of this disease Generally, the macular gaze area is bypassed, so there is no central dark spot. Fundus fluorescein angiography has the common characteristics in the early stage, that is, the asymmetry of the fluorescence intensity of the obstruction area and the small unobstructed area on the same optic disc, see fluorescent filling delaying defect, this The asymmetry is roughly equivalent to the defect of the visual field. The vicinity of the optic disc with visual field defect has localized low fluorescence, and the choroid at this site also exhibits fluorescent charging. Slow.

Differential diagnosis:

Ischemic optic neuropathy, often confused with acute optic discitis, optic disc edema of intracranial space-occupying lesions, and Foster-Kennedy syndrome, should be well identified.

Acute optic discitis

The incidence is very urgent, the visual impairment is serious. Many patients can only see manual or even no light perception. The visual field examination has a huge central dark spot and the surrounding visual field is narrowed. The degree of optic disc edema is not high, but at the same time there is obvious congestion. The late optic nerve showed a secondary atrophy change.

Ischemic optic neuropathy, visual acuity is not serious, although the optic disc has edema, but congestion is not obvious, there is a typical visual field change, the late optic nerve is a primary atrophy.

2. Ocular edema of intracranial space-occupying lesions

Multiple eyes and eyes occur at the same time, the degree of optic disc edema is high, the optic disc is congested obviously, the vein is thick, the curvature is more, the bleeding is more, the visual acuity is normal, the visual field only expands the physiological blind spot, there is obvious headache, vomiting history, and other signs of nervous system damage.

3. Foster-Kennedy syndrome

It is characterized by a primary optic nerve atrophy and another optic disc edema. The clinical significance is that there is a lesion under the frontal lobe near the cranial fossa on the optic atrophy side, which directly oppresses the lateral optic nerve and atrophy. At the same time, due to intracranial The increase in pressure causes optic disc edema on the contralateral side. The difference between it and ischemic optic neuropathy is that the former has many symptoms and signs of increased intracranial pressure, such as headache, vomiting and other signs of nervous system damage, and the degree of optic disc edema is heavier. Clearly congested, retinal varices, visual field examination, edema side physiological blind spot enlargement, atrophic side with central dark spot, and ischemic optic neuropathy visual field changes are different, and there is no increase in intracranial pressure and nervous system signs, careful analysis still It is not difficult to distinguish.

4. Optic nerve papillitis

5. Optic disc vasculitis

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