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Very often, patients encounter such a problem as intraocular pressure, which in turn causes a number of pathological conditions. In order to detect and prevent this in time, doctors prescribe a special test called tonometry.
The main purpose of eye tonometry is to diagnose glaucoma in a timely manner. This is a serious disease that can result in a complete loss of visual functions, that is, blindness. This can happen because intraocular pressure damages the optic nerve.
During eye tonometry, doctors use a special device called a tonometer. It measures intraocular pressure. The device shows the reaction of the cornea.
Before the procedure, local anesthesia is performed by instillation of drops with an analgesic effect.
What is the essence of eye tonometry?
Tonometry of the eyeball is the most popular technique that allows you to accurately measure intraocular pressure. Also, specialists can track how the pressure level in the right and left eyes changes over time, i.e. follow the progress of the disease. The device affects the cornea, and if the patient is doing well, then the deformation of the sphere of the eye does not go beyond the permissible limits.
With increased or decreased intraocular pressure, we can safely say that the patient has serious pathological processes. This procedure should be carried out periodically even for healthy people in order to timely identify any deviations.
Indications and contraindications for eye tonometry
Definitely, manipulation is not carried out for patients who have an allergic reaction to anesthetic drops. It is impossible to carry out the procedure without them. The exception is a non-contact tonometer.
Also, people with eye diseases of a viral or bacterial nature should refrain from tonometry of the eyeballs; trauma or violation of the integrity of the retina; myopia of a high degree; diseases of the transparent outer shell of the eyes.
Also, doctors forbid such a procedure for patients who are under the influence of alcohol, drugs or in an unbalanced state (disturbed mental system).
Tonometry of the eyeball is performed in patients with:
- chronic increased intraocular pressure;
- detachment of the inner shell of the eyeball, which is responsible for the perception of the color palette;
- pathological processes affecting the cardiovascular system;
- neurological diseases;
- diseases of the endocrine system;
- violations of the development of the eyeball;
- complications after the operation.
Ophthalmologists advise patients over 40 years of age to undergo this diagnostic event once a year.
Types of eye tonometry
To date, there are four types of tonometry. The principle of the procedure is almost the same, different devices are used.
Applanation tonometer
This type of tonometer allows you to influence the cornea as little as possible. In addition to the tonometer, the ophthalmologist additionally uses a microscope and a slit lamp to fully examine your eye. The applanation tonometer is considered the most accurate and is used after the patient has passed a standard vision test.
Electronic blood pressure monitor
To measure intraocular pressure in the eyeball, this type of tonometer is more often used. It also stands out for its accuracy, but at the same time, its readings can differ significantly from the applanation one. A special sensor of an electronic tonometer is applied to the outer mucous membrane of your eye, which slowly begins to read pressure readings. All readings are recorded on a small computer panel.
Non-contact tonometer
It is also called a pneumotonometer. Nothing is attached to your eye during the procedure. How then is the pressure measured? The fact is that the measurement is carried out by supplying air. Unfortunately, the contactless procedure cannot be called accurate. But it is still used in ophthalmic practice, namely, when measuring intraocular pressure in children. Doctors can also prescribe the procedure to patients who have just had eye surgery, and any contact can cause serious complications. During the manipulation, the patient does not need anesthesia drops.
Schiotz Impression Tonometer
To measure pressure, doctors use a special rod that gently acts on the outer shell of the eye, pressing it. The ophthalmologist then places small weights on the second part of the apparatus. Conclusions are obtained as a result of calculating the weight, which is necessary in order to return the mucous membrane to its previous position. It is used very rarely, as many scientific studies have not proven the reliability of its results. It can still be found with doctors who come on call to the house.
What is the norm of intracranial pressure for a person?
For each tonometer, the norm is different. It is also impossible to say exactly what pressure a healthy person should have. Like blood pressure, eye pressure can change over the years. It should be noted that intraocular pressure is always higher in men than in women. Therefore, it is impossible to accurately establish the boundaries of normal indicators.
If a person does not have serious abnormalities, then the pressure can fluctuate within 10-21 millimeters of mercury. If the intraocular pressure indicators exceed at least a few values, then the patient can be sent for additional diagnostics.
An ophthalmologist has the right to diagnose a patient with glaucoma if his intraocular pressure is 26 or more millimeters of mercury. At the same time, we can safely say that glaucoma is at an advanced stage.
There are frequent cases when a patient was diagnosed with intraocular pressure with indicators of 19-22 millimeters of mercury, but pathological processes affecting the optic nerves were not diagnosed. Then the diagnosis of ocular hypertension is made. This is not a sign of glaucoma, but requires therapy, since there is a risk of transformation into this disease.
Tonometry is one of the simplest procedures that does not cause serious consequences and does not injure the organs of vision.
Ophthalmologists recommend going through it once a year, even if there are no serious reasons for worry. But the doctor will be able to diagnose the prerequisites for the development of glaucoma in time. This is especially true for people over 40 years of age.