Ocular rigidity was measured in a total of 560 routine office patients with use of Friedenwald's tonometric method of paired weights in conjunction with his 1955 tables. Patients were discarded from consideration When inadequate cooperation prevented a measurement free of lid squeezing or ocular movement. Tonometric measurements lower than 3 or higher than 12 on the scale were also discarded. Contrary to my own expectations I found that children could often be readily examined. Presently there appears to be a difference of opinion as to whether the coefficient of ocular rigidity as formulated by Friedenwald1is in actuality a constant for the individual eye. The tables of intraocular pressure for the indentation tonometer as Well as the procedure of tonography are based in part on the concept of an average ocular rigidity of 0.0215, constant in each eye under all circumstances of intraocular pressure. If the coefficient is found