This is a term which is very rarely used by opticians these days. It is basically a genric term descibing absolutely any abnormal focusing condition within the optical system of the eye that results in the need for prescription lenses to be prescribed.
Examples of this term are:
This Term is occasionally used when an optician is reffering a patient to a Doctor for High Blood Pressure or perhaps Diabetes. In these cases a doctor won't really need to know the specifics of a focusing problem, because the optician will have reffered the patient having found signs in the back of the eye that High Blood pressure or Diabetes may exist. In this case the specific focusing dissorder isn't really relevant in the Opticians report to the Doctor.