Eye, or more precisely, intraocular pressure (IOP) is the pressure of the vitreous and eye fluid on the capsule of the eye from the inside, which ensures its maintenance in tone. It can be elevated and in rare cases reduced, which is caused by different ophthalmologic diseases or congenital anatomical features of the structure of the eye. We will talk about the norm of eye pressure, which is typical for a healthy person.
What is the norm of eye pressure?
It is impossible to judge the indicators of healthy pressure inside the eye unambiguously, since there are several different methods of measuring it and the corresponding instruments at once. Their testimony is incorrect to compare, and this should be remembered by asking the common question "What is the norm of eye pressure?". In fact, the answer to this question will be the counter-question: "What method of pressure was measured?".
How is eye pressure checked?
To clarify the "true" intraocular pressure can be a manometric method, which involves the introduction of a special measuring needle into the anterior chamber of the cornea. Do not be afraid - this method is purely theoretical, doctors in clinical practice do not resort to it.
In the office of an ophthalmologist, you can suggest indirect ways of measuring the pressure of the fundus (the norm, as we have already noted, will differ in each case):
- Tonometry according to Maklakov;
- contactless tonometry;
- ICare tonometers;
- Goldman's tonometers;
- Pascal tonometers.
For all instruments, the measurements are the same: the device measures the eye's response to the force applied to it. Ophthalmologists with experience can detect symptoms of deviation of the eye pressure norm even without measurement, simply by pressing fingers on the patient's eyes. However, in the treatment of serious diseases ( glaucoma , for example), measure this figure to within a millimeter of mercury.
Measurement features
So, answering the question, which eye pressure is considered the norm, we note that all the listed methods except the first show the true IOP, and its value fluctuates within the limits of 10 - 21 mm Hg. Art. (for the Goldman method and ICare: 9 - 21 mm Hg). At the same time, tonometry according to Maklakov, which in the CIS countries is the most common method of measuring IOP, involves the displacement of a greater volume of fluid from the eye chambers during the procedure, and therefore the values of the norm of eye pressure in women and men are higher than in previous methods. In a healthy person, the Maklakov device shows an IOP within the range of 12 to 25 mm Hg. and this pressure is called tonometric.
The method of pneumotonometry has almost outlived itself, although in some medical institutions it is still used. Often pneumotonometry is confused with contactless tonometry, which also implies flattening of the cornea by the flow of air.
Is it painful to measure IOP?
The procedure for measuring eye pressure using the Maklakov method involves placing a special weight on the patient's open eye. Beforehand, an anesthetic is injected into the eyes, but the risk of infection with the subsequent development of conjunctivitis and discomfort still accompanies this not very modern but still popular method of investigation.
Contactless tonometry is offered by most private clinics and does not involve direct contact with the mucous eye. Metering
Tonometers ICare, Goldman and Pascal also cause a minimum of unpleasant sensations, however, because of the complexity of these devices and their considerable cost, not every medical institution can afford such studies.
It is worth noting that in the treatment of any ophthalmic disease it is best to resort to the same method every time - for example, the eye pressure in glaucoma does not tolerate inaccuracies, and therefore it is wrong to carry out measurements on fundamentally different instruments and even dangerous.