张力测定法

定义

张力测定法 is a test to measure the pressure inside your eyes. 该测试用于筛选 青光眼. It is also used to measure how well 青光眼 treatment is working.

选择的名字

Intraocular pressure (IOP) measurement; 青光眼 test; Goldmann applanation tonometry (GAT)

如何执行测试

There are three main methods of measuring eye pressure.

The most accurate method measures the force needed to flatten an area of the cornea.

• The surface of the eye is numbed with eye drops. A fine strip of paper stained with orange dye is held to the side of the eye. The dye stains the front of the eye to help with the exam. Sometimes the dye is in the numbing drops.
• You will rest your chin and forehead on the support of a 裂隙灯 这样你的头才会稳定. You will be asked to keep your eyes open and to look straight ahead. The lamp is moved forward until the tip of the tonometer just touches the cornea.
• Blue light is used so that the orange dye will glow green. The health care provider looks through the eyepiece on the slit-lamp and adjusts a dial on the machine to give the pressure reading.
• There is no discomfort with the test.

A second method uses a handheld device shaped like a pen. You are given numbing eye drops to prevent any discomfort. The device touches the surface of the cornea and instantly records eye pressure.

The last method is the noncontact method (air puff). In this method, your chin rests on a device similar to a 裂隙灯.

• You stare straight into the examining device. When you are at the correct distance from the device, a tiny beam of light reflects off of your cornea onto a detector.
• 执行测试的时间, a puff of air will slightly flatten the cornea; how much it flattens depends on the eye pressure.
• This causes the tiny beam of light to move to a different spot on the detector. The instrument calculates eye pressure by looking at how far the beam of light moved.

如何准备考试

Remove contact lenses before the exam. The dye can permanently stain contact lenses.

Tell your provider if you have a history of 角膜溃疡或眼部感染, or a history of 青光眼 in your family. Always tell your provider what medicines you are taking.

考试的感觉如何

If numbing eye drops were used, you should not have any pain. 在非接触法中, you may feel mild pressure on your eye for a brief moment from the air puff.

为什么要进行测试

张力测定法 is a test to measure the pressure inside your eyes. 该测试用于筛选 青光眼 and to measure how well 青光眼 treatment is working.

40岁以上的人, 尤其是非裔美国人, have the highest risk for developing 青光眼. Regular eye exams can help detect 青光眼 early. If it is detected early, 青光眼 can be treated before too much damage is done.

The test may also be done before and after eye surgery.

正常的结果

A normal result means your eye pressure is within the normal range. The normal eye pressure range is 10 to 21 mm Hg.

The thickness of your cornea can affect measurements. Normal eyes with thick corneas have higher readings, and normal eyes with thin corneas have lower readings. A thin cornea with a high reading may be very abnormal (the actual eye pressure will be higher than shown on the tonometer).

A corneal thickness measurement (pachymetry) is needed to get a correct pressure measurement.

Talk to your provider about the meaning of your specific test results.

异常结果意味着什么

异常结果可能是由于:

• 青光眼
• 眼前房出血 (blood in the front chamber of the eye)
• 眼睛发炎
• 眼睛或头部受伤

风险

If the applanation method is used, there is a small chance the cornea may be scratched (角膜擦伤). The scratch will normally heal within a few days.

参考文献

陈S，李BD, Al-Aswad LA. 青光眼的临床检查. 见:Yanoff M, Duker JS编. 眼科学. 6日艾德. Philadelphia, PA: Elsevier; 2023:chap 10.4.

努普KJ，丹尼斯WR. 眼科手术. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7日艾德. Philadelphia, PA: Elsevier; 2019:chap 62.

鲑鱼摩根富林明. 青光眼. 在:鲑鱼JF, ed. 坎斯基临床眼科学. 9日艾德. Philadelphia, PA: Elsevier; 2020:chap 11.