Certified Paraoptometric (CPO) Practice Exam 2025

Which type of lens should always be kept in solution when being stored?

1. Gas-permeable

2. Soft

3. Rigid

4. Scleral

The correct answer is: Soft

The correct type of lens that should always be kept in solution when being stored is soft lenses. Soft contact lenses are made from hydrophilic materials that are designed to retain moisture. When stored in a solution, they are less likely to dry out, which could potentially damage the lens and make it unusable. The solution not only keeps the lenses hydrated but also helps to preserve their shape and optical properties. In contrast, gas-permeable lenses, when not in use, can be stored in a dry environment and do not necessarily require a solution as they are made from rigid materials that are less susceptible to damage from desiccation. Rigid lenses also do not need to be immersed in solution when stored, as their composition allows for greater durability outside of liquid. Scleral lenses, while they do require a moist environment when worn, can also be stored in a disinfecting solution, but their care is a bit different from that of soft lenses. Proper practices may vary based on the specific manufacturer recommendations and patient instructions.