Open angle glaucoma

Introduction to open angle glaucoma Open-angle glaucoma is also called chronic simple glaucoma (chronicsimpleglaucoma), such glaucoma is more common, more common in middle-aged people, young people can also occur, often bilateral, slow onset of intraocular pressure gradually increased, angle It is always open, and there are no obvious symptoms. It is often found when there is significant damage to the visual field of vision in the late stage. Therefore, early diagnosis is very important. There is no obvious discomfort at the beginning of the disease. When it develops to a certain extent, it feels mild headache, eye pain, blurred vision and rainbow vision. It disappears after rest, so it is easy to mistake the visual fatigue, and the central vision can be maintained. Long-term unchanged, but the visual field can appear early, and finally, due to the compression of long-term high intraocular pressure, the optic nerve gradually shrinks, the visual field shrinks, disappears and becomes blind. There is no obvious sign in the external eye during the whole course, only mild in the late pupil. Expanded, the iris shrinks. basic knowledge The proportion of sickness: 0.6% - 0.9% Susceptible people: more common in middle-aged people Mode of infection: non-infectious Complications: iridocyclitis, malignant glaucoma

Open angle glaucoma cause

Genetic factors (25%):

Some patients with this disease have genetic predisposition, such as TIGR gene, OPTN gene and so on. Some patients have a family history of glaucoma. Early cases are often accidentally discovered during routine eye examinations.

Increased intraocular pressure (45%):

The main risk factor for the disease is increased intraocular pressure. The reason for the increase in intraocular pressure is that the outflow of aqueous humor is blocked by the trabecular meshwork-Schlemm tube system. The disease is closely related to intraocular pressure, and the intraocular pressure can be elevated or normal.

Other factors (10%):

There are other risk factors for the occurrence of this disease, such as optic nerve ischemia, such as decreased tolerance to intraocular pressure, thin corneal thickness and so on.

Pathophysiology

The iris is in close contact with the front surface of the lens. When the aqueous humor passes over the pupil, the resistance increases. The pressure in the posterior chamber is relatively higher than that in the anterior chamber, and the iris is pushed forward to make the anterior chamber shallower, and the angle of the chamber is further narrowed. This is the opening angle. The pupillary block mechanism of glaucoma. With age, the thickness of the lens increases, the anterior chamber is shallower, the pupillary block is aggravated, and the incidence of open-angle glaucoma is increased. Once the peripheral iris is in contact with the trabecular meshwork, the corner of the room is closed, the intraocular pressure rises sharply, causing an acute attack, and an open-angle glaucoma occurs.

Changes in weather and seasonal changes have a great impact on the physiological function of the eye. If the temperature difference is large, it will affect the regulation of ocular nerves and cause glaucoma attacks. Therefore, the recurrence of glaucoma occurs mostly in winter.

Open angle glaucoma prevention

Early detection, early treatment, especially those with a family history of glaucoma, should do regular eye examinations, pay attention to rest and sleep, avoid overwork and emotional agitation, read or engage in close-range workers, and have sufficient light.

1, pay attention to supplement nutrition, eat more fresh vegetables and fruits, avoid drinking and spicy foods such as spicy;

2, in addition to maintain a regular life, to achieve a comfortable mood, work and rest, keep the eyes clean, to avoid infection;

3, diabetes, hypotension, retinal vascular disease and elevated intraocular pressure after glucocorticoid eye drops, etc., you should pay attention to the possibility of open angle glaucoma, should be regularly checked by an ophthalmologist to avoid missed diagnosis or misdiagnosis;

4, can be prevented by reasonable and careful use of hormonal eye drops.

Open angle glaucoma complications Complications, iridocyclitis, malignant glaucoma

Complications usually occur after glaucoma surgery, such as anterior chamber hemorrhage, delayed anterior chamber formation or no anterior chamber, secondary iridocyclitis, malignant glaucoma.

Open-angle glaucoma symptoms common symptoms eye pain high intraocular pressure rainbow vision fatigue iris segmental atrophy droplet cornea

There is no obvious discomfort at the beginning of the disease. When it develops to a certain extent, it feels mild headache, eye pain, blurred vision and rainbow vision. It disappears after rest, so it is easy to mistake the visual fatigue, and the central vision can be maintained. Long-term unchanged, but the visual field can appear early, and finally, due to the compression of long-term high intraocular pressure, the optic nerve gradually shrinks, the visual field shrinks, disappears and becomes blind. There is no obvious sign in the external eye during the whole course, only mild in the late pupil. Expanded, the iris shrinks.

Open angle glaucoma examination

Early diagnosis of chronic simple glaucoma is extremely important for protecting visual function.

1. Intraocular pressure: In the early stage, the intraocular pressure is unstable, and the intraocular pressure rises only a few hours in a day. Therefore, measuring the 24-hour intraocular pressure curve is helpful for diagnosis. As the disease progresses, the base pressure gradually increases, when the base pressure When the difference between the peak pressure and the peak pressure is very small or close to zero, it means that the disease has reached the final stage.

2, fundus changes: optic disc sag enlargement is one of the common signs, early optic disc no significant changes, with the development of the disease, the physiological depression of the optic disc gradually enlarged and deepened, and finally can reach the edge, forming a typical glaucoma cup-shaped depression, optic disc Adjacent retinal nerve fiber layer damage is the basis of visual field defects. It appears before the optic disc or visual field changes. Therefore, it can be used as one of the early diagnostic indicators of open-angle glaucoma. When examining, it should be fully dilated and use sufficient brightness without redness. Direct optical ophthalmoscope.

3, visual field: open-angle glaucoma in the optic disc when pathological changes, there will be visual field defects.

4, anterior chamber angle: open angle glaucoma is mostly wide angle, even if the intraocular pressure is elevated is still open.

5. Excitation test: The following test can be performed when the early diagnosis of open angle glaucoma is difficult.

(1) Drinking water test: Stop eating after 10 o'clock in the evening before the test. Drink water 1000 ml in the morning on the next morning, and measure the intraocular pressure before drinking water. The eye pressure is measured every 15 minutes after drinking water, for a total of 4 times, such as drinking water. The posterior intraocular pressure is higher than 8 mm Hg above drinking water. The anti-glaucoma drug should be stopped for at least 48 hours before the examination. Those suffering from cardiovascular disease, kidney disease and severe ulcer disease are hanged.

(2) Tolazoline test: After measuring intraocular pressure, 10 mg of tolazoline was injected under the conjunctiva, and then the intraocular pressure was measured every 15 minutes for 4-6 times. The intraocular pressure increased by 1.97 kPa after the injection. (9 mm Hg) is positive, and tolasilin can increase intraocular pressure because it has the effect of dilating blood vessels, which can increase the production of aqueous humor.

(3) Eye compression test: one of the more reliable tests for the diagnosis of open angle glaucoma.

6, special inspection:

(1) Farnsworth Panel D15 and Farnsworth 100-Hue color vision examination: early patients often have blue-yellow dysfunction.

(2) contrast sensitivity test: In patients with open-angle glaucoma, the sensitivity threshold is increased and the sensitivity is reduced.

(3) Pattern e-lectroretinogram: The amplitude of the early patients is reduced.

(4) Pattern visual evoked potentials: The pattern visual evoked potential amplitude of patients with open-angle glaucoma is reduced and the latency is prolonged.

The positive results of the above tests must be considered in conjunction with changes in intraocular pressure, optic disc and visual field.

Open angle glaucoma diagnosis

Diagnostic points:

(1) Abnormal intraocular pressure: The 24-hour intraocular pressure curve fluctuates greatly, which is greater than 10 mmHg (1.3 kPa).

(2) Intraocular pressure tracing: C value is reduced, less than 0.12.

(3) Fundus examination: the nipple depression is large, the vertical diameter transverse diameter, the cup/disk ratio 0.6, or the difference between the two sides is 0.2, the area along the disk is narrowed, and the line is bleeding.

(4) Visual field change: from the side center dark point, the stepped or arched field of view defect, the peripheral field of view is reduced.

The onset characteristics of open angle glaucoma:

(1) The disease is concealed and most of them have no symptoms. The intraocular pressure is mostly around 35-50mmHg.

(2) The course of the disease is progressive, and many patients are blinded unconsciously.

(3) Due to the inability to treat in time, the condition is often late or absolute.

Differential diagnosis

To be differentiated from angle-closure glaucoma, in addition to acute iritis, conjunctivitis and so on.

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