Date. 1884.

Author. Alexei N. Maklakov (1837–1895) – ophthalmologist, Doctor of Medicine, Professor of Emperor Moscow University.

Aims. Exact measurement of intraocular pressure.

Tasks. Creation of an instrument for most accurate measurement of intraocular pressure.

Construction and principles of operation. Maklakov tonometer has a fixed force (a weight) and consists of a metal cylinder (4 centimeters high) with small numbs on ends in form of hemispheres, facing their bases outside with round “milk-glass” plates (1 cm in diameter) attached inside. A freely moving piece of lead inside the cylinder ensures the low centre of gravity.

When being used the instrument is hung on a special shaft in the form of still blade with a cut in the middle narrowing towards the end of it; the cylinder is put through the wide part of the cut and is moved towards the narrow part so that it can’t fall through, then it is secured with a special latch.

When the patient is looking straight ahead the cylinder is lowered onto the cornea so that the cylinder is pressing on the cornea with its whole weight, after the contact the instrument is removed. At the moment of full contact the cornea is being flattened and the flattened area is printed onto a painted surface in the form of a white round spot, because the paint (or ink) after contacting with the cornea dissolve and linger on it. In order to get the “print” of the spot – the “tonogram” – the plate of the tonometer is printed onto a piece of paper, wetted with a little alcohol; the white area in the centre of the inkblot matches the area of the flattened cornea. The diameter of the white spot is an objective demonstration of the intraocular pressure. For measuring it A. N. Maklakov suggested a special scale, based on the principle of a proportioned pair of compasses, which looks like a see-through blade with an isosceles triangle on it.


Maklakov tonometer is used all over the world since it has been created and until the present day.

Publication. Maklakov A. N. Ophthalmology. Journal “Surgical society chronical”, 1884; Journal “Medical review”, 1884, vol. 22; Journal “Doctor”, 1885; Journal «Archive d'Ophthalmologie», № 4, 1885.

Value. One of the advantages of the Maklakov tonometer is that it is simple in use.

Maklakov tonometer is classic and consummate in terms of simplicity and preciseness of measurements even today.


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