There seems to be no type of test or measurement in the practice of ophthalmology more acutely in need of standardization than tonometry. Among the essentials for standardization the following may be mentioned: 1. A clearer conception of what is measured in tonometry. 2. Preferably the adoption of one type of instrument as the standard of practice. 3. A determination of all the variable factors that influence the measurements in tonometry. 4. Devices and methods for the control of these factors or for reducing their influence to a minimum. 5. The better care of tonometers. 6. The devising of a checking standard by means of which the performance or reading of an instrument at any one time can be compared with the performance at any other time or with that of any other instrument of its type. 7. The careful selection of an instrument of a given