Ophthalmic tonometry is a measurement of intraocular pressure, which is important in the diagnosis of glaucoma (see). The simplest is the so-called finger tonometry. In this method, the researcher puts the ends of the index fingers on the upper eyelid, first one, then the other eye. Investigated while looking down without squeezing the eyelids. The tips of the fingers alternately lightly press on the eyeball. The obtained impression of the density of the eye may be an approximate characteristic of the state of intraocular pressure.
More precisely, the measurement of intraocular pressure (see) is performed using Maklakov eye tonometers.
Measurement of intraocular pressure using a Maklakov tonometer.
The device is a small cylinder weighing 10 g, the ends of which end in milk glass pads with a diameter of 10 mm. Before the investigation, the areas are smeared with a thin layer of special paint (Bismarckbrown, Collargol, Methylene Blue). The study is carried out at the position of the patient lying after preliminary instillation into the conjunctival sac of the examined eye of a 0.5% solution of dikain. Using the holder, the tonometer is placed on the cornea (Fig.) And held in a vertical position for about 1 sec., Then quickly removed. On the site of the tonometer in the area of contact with the cornea, a bright spot is obtained, which is printed on paper slightly moistened with alcohol. This kind of print is called a tonogram, its area depends on the size of intraocular pressure: the higher the intraocular pressure, the less will be the area of the print and the resulting circle, and vice versa. There is a special ruler for converting the diameter of the print circle to the value of intraocular pressure (in millimeters of mercury).
Eye tonometers are produced in the form of a set of tonometers of different weights. Tonometry in the eye offices are usually carried out by average health workers.