This instrument is an auto ref/keratometer which contains both a refractometer and a keratometer in one unit. The refractometer objectively measures the refractive power of the patient’s eyes with infrared rays to obtain spherical, cylindrical powers and cylinder axis of the lens which may correct the patient’s vision into emmetropia. The keratometer measures the corneal curvature (corneal refractive power), angle of corneal meridian, and corneal cylindrical power.
This instrument has a main body and a measuring unit integrated on one base. On the base is a chin rest on the patient’s side and a printer on the operator’s side which makes an output of measurement results. On the main body is a TV monitor, a control panel, and a joystick, which are used to make alignments or manipulation. The measuring unit has a measuring window, where the patient looks into and where the infrared ray radiates on the patient’s eye. Also, there is an auto-tracking mechanism which moves the measuring unit to follow eye movement, and an auto-shot function, which makes serial measurement start automatically when the instrument becomes correctly focused.
Information courtesy of Nidek ARK-700a User Manual