## 2 Materials and Methods  
The experiments included four models of TPRs: Double 3 by Double Robotics [14], Ohmni by Ohmnilabs [15], and Temi 2 and Temi 3 by Roboteam Home Technology [16]. They consisted of two separate sets of measurements: (1) measuring visual acuity using the Snellen and LogMAR charts at a distance of 3 m and with an illuminance of approximately 600 lux, as recommended for these charts [10; 17]--(\"It is recommended that VA assessment always be performed between 400 lux and 600 lux, as this limits any effect of illuminance change to 0.012 LogMAR\"); and (2) measuring the text readability on the wall projector in the class at the distances of 5 m and 10 m. Image acquisition was performed by taking screenshots with the Windows Snipping tool in the lossless format PNG (Portable Network Graphics) [18; 19] and using the robots' integrated functions of storing still images from the camera, where available. Codecs shape video quality, varying even with the same devices. During internet data transmission, dynamic adjustments prevent delays. In our TPR experiment, undisclosed compression details and fixed settings risked video quality decline with low bandwidth. To counter, we used ample network bandwidth, providing ample safe margin compared to the minimal requirements as stated by the manufacturers (Ohmni: 3 Mbps upload and download, as stated on [[https://ohmnilabs.com/products/customers/faq/#spec](https://ohmnilabs.com/products/customers/faq/#spec)]([https://ohmnilabs.com/products/customers/faq/#spec](https://ohmnilabs.com/products/customers/faq/#spec)) accessed on 24 December 2023; Double 3: 4.5 Mbps, as stated on [[https://doublerobotics.my.site.com/s/article/network-connectivity-requirements](https://doublerobotics.my.site.com/s/article/network-connectivity-requirements)]([https://doublerobotics.my.site.com/s/article/network-connectivity-requirements](https://doublerobotics.my.site.com/s/article/network-connectivity-requirements)) accessed on 24 December 2023; Temi: at least 3 Mbps upload and 3 Mbps download speeds, as stated on [[https://temi-guide.readthedocs.io/en/latest/network-admin/03_temi-robot.html#temi-robot-wifi-requirements](https://temi-guide.readthedocs.io/en/latest/network-admin/03_temi-robot.html#temi-robot-wifi-requirements)]([https://temi-guide.readthedocs.io/en/latest/network-admin/03_temi-robot.html#temi-robot-wifi-requirements](https://temi-guide.readthedocs.io/en/latest/network-admin/03_temi-robot.html#temi-robot-wifi-requirements)) accessed on 24 December 2023), ensuring optimal performance despite unknown technical details. Data transfer from TPRs to the operator was conducted via the cloud service; therefore, the quality of the internet connection played a significant role in the experiment. The building where the experiment took place is connected to the internet using two channels with a bandwidth of 1 Gbit each. Robots were connected to a 2.4 GHz wireless network. The experiment took place on Sunday, with no other people present in the building and therefore with minimal interference. Network connection speed was measured using the Speedtest [20] service, with a connection to Telia Eesti AS servers (Table 1). \begin{table}
\begin{tabular}{c c c c c c} \hline
**IP Address** & **Download, Megabits** & **Upload, Megabits** & **Latency, ms** & **Server Name** & **Distance, Miles** & **Connection Mode** \\ \hline
193.40.xxx.xxx & 311.17 & 267.43 & 3 & Tallinn & 0 & multi \\
90.190.xxx.xxx & 41.92 & 20.19 & 9 & Tallinn & 100 & multi \\ \hline \end{tabular}
\end{table} 
Table 1: Speedtest connection properties report. Double 3 and Ohmni robots have integrated qualitative indicators to inform the user of the networking conditions; they both rated network connection as \"good\" (the highest category according to their scale).