A History of Intraocular Pressure and Its Measurement

Abstract

Doctors have not always associated elevated intraocular pressure with the vision loss from glaucoma. Although several individuals appear to have noted firmness of the eye in this condition as far back as the 10th century, elevated intraocular pressure was not routinely assessed until the latter part of the 19th century. von Graefe developed the first instrument for measuring intraocular pressure in 1865. The first reasonably accurate instrument was the Maklakoff applanation tonometer of the late 19th century; it was in widespread use throughout Eastern Europe until relatively recently. Schiötz developed an indentation tonometer that was widely used throughout the world during the first two thirds of the 20th century. Goldmann's applanation tonometer of 1950 began the era of truly accurate intraocular pressure measurement. It is still the most widely used tonometer in the world. Other devices such as the McKay-Marg tonometer (or its offspring the Tono-Pen), the pneumatonometer, and airpuff applanation tonometers are gaining adherents. The dynamic contour tonometer is the first totally new concept in tonometry in over 100 years. It is probably the most accurate of all the tonometers and is relatively independent of corneal biomechanical properties unlike its predecessors. Transpalpebral tonometers are attractive as they do not require topical anesthesia; however, they add the biomechanical properties of the eyelid to the list of potential errors and have not proven very accurate. The future should, hopefully, bring tonometers that can give diurnal or even longer indications of intraocular pressure variation. Although intraocular pressure elevation (or its absence) no longer can be counted on for diagnostic purposes, the role of intraocular pressure in the management of glaucomatous optic neuropathy remains critical.

Intraocular pressure fluctuation and glaucoma progression: what do we know?

“…The device measures the amount of force required to flatten a section of the cornea, thereby indirectly calculating the IOP 7. A more in-depth discussion of tonometry is beyond the scope of this paper, though Stamper provides an excellent, highly recommended discussion of the topic.…”

Comparison of Intraocular Pressure Measurements Obtained by Icare PRO Rebound Tonometer, Tomey FT-1000 Noncontact Tonometer, and Goldmann Applanation Tonometer in Healthy Subjects

“…Disinfection of the tonometer tip in the clinical setting remains unresolved at this time. 6 During the last decade, various devices have been designed with the intention of being minimally influenced by the individual eye characteristics and to provide noncontact IOP assessment. 7 Icare tonometry is based on the principle of rebound tonometry (RT).…”

A powerless optical microsensor for monitoring intraocular pressure with keratoprostheses

“…The basic operation principle has remained the same: IOP assessment is inferred from the mechanical properties of the cornea and the force that is required to flatten a 3mm 2 area of the cornea [2,3]. This measurement requires the use of a specialized instrument, called the tonometer.…”