Von Graefe's Tonometer 1863

This instrument rested on the forehead and cheek bone by means of two brass feet. The pressure on the central plunger could be varied by the position of the weight on the scale indicator.

Donder's Tonometer 1865

The pressure on the plunger was varied by a spring and the indentation read by a pointer on a circular scale.

Snellen's Tonometer 1872

The indentation was measured by the position of the central pin relative to the other two. The pressure on the central pin was varied by means of a spring. The instrument was stored in a brass cylinder.

Early Descriptions of Intraocular Pressure

10th Century AD: Arabian Surgeon, At-Tabari mentioned the raised tension of the eye in a condition we now know as acute glaucoma.

1348 AD: Sams-ad-Din of Cairo also mentioned the raised tension of the eye.

1622 AD:  Richard Bannister of England described the raised intraocular pressure as determined by palpation of the globe as a distinct sign of eye disease.

1738 AD:  Johann Platner of Leipzig recognised a condition in which the eye became hard.

1818:  Antoine-Pierre Demaurs described glaucoma with raised ocular tension.

1823:  English Physician, G. J. Guthrie wrote that hardness of the eye is characteristic of a disease he called glaucoma.

Thereafter, a rise in intraocular pressure was considered to be a part of the disease process occurring in some eyes.

Measurement tools

1826:  William Bowman used digital tonometry as a routine examination test.

1863: Albrecht von Grafe designed the first instrument to attempt to measure intraocular pressure.

Further instruments followed, notably by Donders in 1865 and Preistly-Smith in 1880.
These instruments were all of the indentation type and rested on the sclera (Cocaine was not used until 1884).

1867:  Adolph Weber designed an aplanation tonometer, this was not generally accepted.

1872:  Prominent Ophthalmologists such as Snellen and Landolt thought that estimation in intraocular pressure by palpation with the fingers was still the method of choice.

1905:  Hjalmar Schiotz produced his indentation tonometer. This made tonometry a simple and routine clinical test.

1912:  Gradle designs modification of the Schiotz instrument. Footplate dimensions are said to be more critical.

1912: Mc Lean's indentation tonometer. He stated that the compared manometric pressure of enucleatated eyes with the reading of his tonometer and concluded that the normal range of intraocular pressure was 22-40 nn Hg.

1924: Schiotz X tonometer

1954: Goldman' s aplanation tonometer

1967: Tonomat designed by Posner and Inglima. Based on Maklakov's tonometer. Not as simple or as quick to use as Goldman's instrument. Please click here for instructions.

The development of further tonometers that have been described have all been of the aplanation type.

Maklakov Tonometer, First produced in 1885

The white end of the tonometer is coated with a special dye solution. The tonometer is suspended by the wire handle and allowed to rest on the surface of the cornea. The cornea is thereby aplanated and the area of the tonometer end in contact with the cornea loses its dye. The tonometer end is then pressed onto special paper and a circle of dye produced, the diameter of which corresponds to the intraocular pressure. A special scale is placed over the ring converting it into intraocular pressure.

Tonometers of various weights enable a measure of ocular rigidity to be made.

Schiotz Indentation Tonometer 1905

Schiotz Tonometer 1924

Schiotz X Tonometer 1925

Advice from the pamphlet enclosed with the Schiotz X Tonometer:

"Hospitals and eye-specialists should have two Tonometers for cross-checking. If a Tonometer needs adjustment or repair, it should be sent to me. I am the only one able to guarantee an accurate adjustment. Notice that after repair a Tonometer always needs adjustment. Warning is given against imitations, even if they bear the name of Professor Schiotz. The legitimate Professor Schiotz Tonometer is made only by me, and my Tonometer are guaranteed to confirm to the orginal specifications of Professor Schiotz. With each Tonometer follows a guarantee signed by me, to prove that the Tonometer is accurately adjusted. On top of each Tonometer-case is printed my trademark, <<Schiotz Norway>> "

Gradle Tonometer 1912

McLeans Indentation Tonometer

Tonomat Tonometer

Developed by Adolph Posner and Richard Inglima, USA 1964

Click here for Instructions

This is a development of the Maklakov Tonometer. The cornea is aplanated using a standard weighted probe that has a disposable plastic end plate.

An impression is made from the ring measured with a built in scale.