“…Because we did not find potential blind spots for other domains, we did not consider it necessary or practical to include additional terms (e.g., geometry or statistical reasoning). 2 This meant that studies were not included that primarily addressed methodological questions (e.g.,Schindler & Lilienthal, 2017) or studies where gaze replays were used as stimuli, but that did not analyze the eye-tracking data itself (e.g.,Gallagher-Mitchell, Simms, & Litchfield, 2018;van Marlen, van Wermeskerken, Jarodzka, & van Gog, 2016van Wermeskerken, Litchfield, & van Gog, 2018;Wang, Pi, & Hu, 2018).3 Note that the review byLilienthal and Schindler (2019) included another 25 PME papers that we did not include in our review for the following reasons: 21 were short reports, 2 did not directly relate data to mathematics education, and 2 have since been published as journal articles that are included in our review.…”