The invention relates to a device for studying keratometric power values and radii. The device is disposed in an optical instrument and can be used to simulate optometry, contactology and ophthalmology tests without using a human eye. The invention can also be used for instrument calibration for objective testing. The device includes a base (portion A) with a notch (3) for securing a supporting part (part B) having an inclined plane which ensures that the device is maintained perpendicular to the bar to which it is secured. Human eye simulators (part C) are affixed on top of the supporting part (B) and said simulators are designed to simulate a keratometric astigmatism in the range of the human cornea. The device is joined to an optical instrument by means of portion A which is provided with a hole (7) and a screw in the thread (2) provided for this purpose.