What is the purpose of 'Prism' in optical practice?

The purpose of 'Prism' in optical practice is primarily to correct double vision, also known as diplopia. When light passes through a prism, it bends the light rays, allowing for the adjustment of image alignment. This helps to center images for the eyes, making it easier for the brain to fuse both images into a single, clear picture.

In cases where a patient may be experiencing misalignment of the eyes, prisms can be prescribed in lenses to help realign the images being sent to the brain, effectively reducing or eliminating the double vision experienced. This technique is especially useful in conditions where the eyes do not work together as they should, such as strabismus (crossed eyes) or other binocular vision disorders.

While other options mention concepts related to optical solutions, they do not accurately relate to the specific function of prisms. For example, correcting color blindness involves different methods and tools, measuring lens thickness pertains to lens fabrication rather than vision correction, and providing distance correction is more related to prescription lenses that focus light effectively rather than manipulating light paths through prisms.