To find out if the degree has been stable, the optometrist would obtain the history of the eye degree from the patient. If the patient's prescription has remained similar over at least 12 months, the vision is considered to be stable. However, minor fluctuations of 0.25 to 0.50 diopters would usually be accepted, as these may be contributed by eye fatigue or errors during subjective refraction.
If the patient could not remember his/ her eye degree or an eye exam has not been done recently, the optometrist would obtain the patient's latest spectacle or contact lens degree, and ask the patient the current quality of the vision when wearing those visual aids.
