If the corneal surface is irregular due to an injury, keratoconus or other anomality, the mires will be distorted. They may just be slightly irregular in shape or so distorted that they can not even be brought into focus.
If the tear film breaks up the mires may temporarily be distorted.
If the mires are distorted, this should be recorded in the record. The amount of distortion should be indicated, usually as either mild, moderate or severely distorted.
