Maintaining the spherical shape of the eye, its tone, metabolism in tissues and correct microcirculation provides optimal intraocular pressure - the norm in adults of this indicator (ophthalmotonus) should always be at a fixed level. Its value is set in accordance with the volume of inflow and outflow of eye fluids.
What should the intraocular pressure be?
To begin with, it should be noted that there is a true and tonometric ophthalmotonus.
In the first case, the exact value of eye pressure can be determined only by one method: insert the needle of the manometer into the anterior chamber of the eye through the cornea, perform a direct measurement. This technique has not been used in clinical practice for a long time.
Tonometric ophthalmotonus is determined by various techniques and devices:
- Tonometry according to Maklakov;
- contactless tonometry;
- Goldmann's tonometers;
- ICare tonometers;
- Pascal tonometers.
Moreover, an experienced ophthalmologist can approximately estimate the amount of pressure palpatorically, pressing fingers on the eyeballs with closed eyelids.
It is believed that the normal values of the ophthalmotonus should be within 10-21 mm Hg. Art. Any deviation from the indicated boundaries is a pathology and negatively affects the homeostasis of the eyes.
Norms of intraocular pressure by age
The established limits of the considered size are relevant for women of any age. But changes in the eyeball and corneal tissues that occur with aging of the body affect the fixed indicators of the ophthalmotonus.
Thus, the upper limit of the norm of intraocular pressure after 50-60 years is slightly increased - a value of 23 mm Hg is allowed. Art.
Patients with the following pathologies tend to change ophthalmotonus:
- presence of foreign body in the eye;
- low blood pressure or hypotension;
- penetrating eye trauma;
- severe infections and other conditions accompanied by severe dehydration;
- inflammatory diseases of the eyes (irites, uveitis);
- diabetes mellitus with ketoacidosis, ketoacidotic coma;
- retinal detachment ;
- severe chronic liver disease;
- complications after surgical operations;
- kidney diseases;
- underdevelopment of the eyeball;
- overwork, stress;
- hypertonic disease.
The most likely fluctuations in eye pressure in the progression of glaucoma, especially in women over the age of 40 years. Therefore, ophthalmologists recommend to visit the doctor every year for routine preventive examination, which allows a comprehensive assessment of the functioning of the organs of vision and the magnitude of the ophthalmotonus.
What is the norm of intraocular pressure in glaucoma?
The described index depends on the shape and severity of glaucoma . In total there are 4 degrees of this eye disease, each of which has its own values of ophthalmotonus:
- The initial. Intraocular pressure is considered to be relatively normal and does not exceed 26 mm Hg. Art.
- Developed. Ophthalmotonus moderately elevated - 27-32 mm Hg. Art.
- Far behind. Intraocular pressure is greatly increased, exceeding 33 mm Hg. Art.
- Terminal. The values of the ophthalmotonus are much larger than 33 mm Hg. Art.
Intraocular pressure in glaucoma deviates from the norm not sharply, but gradually, as the disease progresses and the resistance to outflow of fluid from the eye chambers increases. For this reason, the patient does not immediately feel an increase in the ophthalmotonus, which makes early diagnosis of glaucoma difficult.