Tonometry-A journey of two centuries

Centuries of research on Glaucoma have not been able to add any factor to ‘Intraocular Pressure (IOP)’ the modification of which can halt the progression of this blinding disease. Therefore, the need for accurate IOP measurement has always been the interest of researchers and industry. An array of instruments has, thus, been developed, each surpassing the errors of the previous modalities. Although all of them have certain advantages, they have their limitations too. The present article puts light on the various developments in the field of tonometry over two centuries starting digital tonometry to the latest developments. It has also briefly touched the factors affecting intraocular pressure and its measurement.