Which type of projection includes adjustments for changing the size of symbols displayed on the screen?

The correct answer is the type of projection that includes adjustments for changing the size of symbols displayed on the screen. This kind of projection is vital in contexts where visual acuity assessments are necessary, allowing for modifications in the size of the symbols or letters based on the patient's needs. This ensures that the visual clarity and detail can be adapted for different levels of visual acuity, facilitating accurate testing and diagnosis.

This type of projection focuses on adjusting variables such as brightness or clarity of symbols in relation to the viewer's distance from the display, which is integral in a clinical setting. Proper adjustment helps in effectively testing the patient's vision, thereby yielding more reliable outcomes.

Other projection types might not have the flexibility or specific adjustments to symbol size, making them less suitable in scenarios where precise measurement of visual acuity is essential.