Special devices have been made to attach to the front of the keratometer to control fixation more accurately and to allow measurement of more points on the cornea.
Such measurements do not give a very accurate representation of the corneal shape since at each fixation point the readings are being taken from two points 3 mm or greater apart. This along with the complex geometry of the cornea makes interpretation of the readings difficult. It may help determine if a particular cornea flattens more or less than average but does not give accurate values.
is now available and gives more accurate information than the keratometer for peripheral corneal shape.
