A person who requires ocular lenses may experience refractive instability.
Refractive instability refers to a significant change in lens prescription over a short period of time, typically within a year.
Risk factors for refractive instability:
(1) medications causing a fluctuation in visual acuity
(2) if female, pregnancy or breastfeeding
(3) diabetes
(4) other endocrine disorders with wide fluctuations in hormone levels
(5) age < 25 years
If refractive instability is detected then it is important to determine the cause.