Microsaccades have been implicated in several perceptual and cognitive functions, including aiding performance in high-acuity visual tasks (Ko, Poletti, & Rucci,
2010; Poletti, Listorti, & Rucci,
2013; Rucci, Iovin, Poletti, & Santini,
2007) and shifts of covert spatial attention in both humans and monkeys (Engbert & Kliegl,
2003; Hafed & Clark,
2002; Hafed, Lovejoy, & Krauzlis,
2011; Lara & Wallis,
2012; Laubrock, Engbert, & Kliegl,
2005; Laubrock, Engbert, Rolfs, & Kliegl,
2007; Rolfs,
2009; Rolfs, Engbert, & Kliegl,
2004; Yuval-Greenberg, Merriam, & Heeger,
2014), though there has been some disagreement regarding this last role (Collewijn & Kowler,
2008; Horowitz, Fine, Fencsik, Yurgenson, & Wolfe,
2007). Arguments about the functional roles of microsaccades rely on accurate definition and detection of microsaccades (Poletti & Rucci,
2016). Microsaccade detection is complicated by motor noise in the eye and measurement noise in the eye tracker. The latter is particularly important in view of the widespread use of video-based infrared eye trackers, which are less invasive than magnetic scleral search coils, but noisier (Hermens,
2015; Träisk, Bolzani, & Ygge,
2005). For example, the popular EyeLink II video-based infrared eye tracker reports a precision of 0.01 deg of visual angle; however, in practice this precision can be worse (Holmqvist et al.,
2011). The low sensitivity, precision, and resolution of video-based eye trackers can cause difficulties in resolving microsaccades (Nyström, Hansen, Andersson, & Hooge,
2016; Poletti & Rucci,
2016).