F 900 and A 900 applanation tonometers provide extreme accuracy for the measurement of intraocular pressure. Measurements are based on the “Goldmann method”, in which the pressure required for maintaining uniform applanation of the corneal surface is measured, and can be undertaken without standardization and calibration difficulties. Versatile, these tonometers can be mounted and combined with the SL 990 slit lamp or other manufacturers’ equipment.