Video from Haley Strategic Partners on their Th1rte3n Sights for pistols... "The HSP TH1RTE3N Glock Handgun sights were designed based on the science of how the human eye acquires sight alignment and sight picture under precision or stress sight picture situations. Handgun sights are installed on a handgun to add more precision; this is what the HSP13 were designed around. Under 'critical stress' shooting, we know that the Body Alarm Response (BAR) instantly takes control and increases the blood flow to the center field of vision. This in return increases your visual efficiency on the threat.

During this immediate process, it is very difficult to focus on anything other than the threat. Your eyes observe, your brain orients, and you then decide on an action to take. During this immediate BAR response process, you will look through your sights with your focal plane fixed on the target due to it being a positive and natural human defense mechanism. With this theory in mind, the widths of the front sight or rear sight notch are irrelevant. The idea that your front sight and or rear notch need to be large for faster target acquisition is misguided, according to current research by visual experts.

However, precision sight picture does matter when the information continues to the higher cognitive portion of the brain during situations where a decision has consciously been made to use a higher level of precision for hostage taker or long-range shots for example. In this case, the HSP 13 sights are designed with a .125 front width sight and a .125 rear sight notch. This will refine the sight picture during the trigger press, decreasing human error and increasing hit probability on a precision target."