Which condition could cause a sudden change in prescription in an adult patient?

The condition that could cause a sudden change in prescription in an adult patient is diabetes. Diabetes can lead to fluctuations in blood glucose levels, which can subsequently affect the shape of the lens in the eye, potentially altering its focusing ability. As a result, a patient may experience changes in vision that necessitate an adjustment in their glasses or contact lens prescription. This phenomenon can occur relatively quickly, particularly in cases of uncontrolled diabetes, where significant changes in blood sugar levels can happen over short periods.

Other conditions like astigmatism, pterygium, and myopia tend to cause more gradual changes in vision and prescription. Astigmatism, which is usually a result of the cornea's irregular shape, is generally stable once diagnosed and does not typically lead to sudden changes in prescription. Similarly, pterygium is a growth on the conjunctiva that may cause discomfort or vision issues but typically does not result in sudden changes in refractive error. Myopia is a refractive error leading to difficulty seeing distant objects, and while it can progress over time, it does not usually cause sudden shifts in visual acuity as diabetes can.