To measure a patient's refractive error, squint and presbyopia, it is used to hold lenses, prism or other tools like pinhole occluder.

Although phoropters, which contains lenses allow a quicker refraction, the trial frame help to test near vision at the patient's preferred working distance and position.

[1] Since it is portable, a trial frame is ideal for vision and refraction screening during home (domiciliary) visits and outreach camps.

[5] The majority of trial frames are manufactured using combinations of metal and plastic parts using injection moulding techniques.

Newer trial frame like the OICO TF-4use additive SLS 3D printing to reduce the number of parts.