Background and Objective: Medication errors are recognized as a serious threat to patient safety that can lead to adverse health outcomes and increased healthcare costs. This study evaluated the impact of font size, font type, and correlated color temperature (CCT) on the readability of printed medication prescriptions.

Materials and Methods: This experimental study was conducted at an education hospital with the participation of 30 nurses. Four levels of correlated color temperature (CCT) (2885, 4003, 6132, and 9973 K) at a constant illuminance of 150 lx, along with three font types (Tahoma, Zar, and Yekan) in three different sizes (9, 11, and 13 pt) were evaluated. Data analysis was performed using linear mixed models (LMM).

Results: The results revealed that CCT has a significant effect on readability. The highest error rate was observed at 2885 K, significantly greater than 6132 K (P = 0.004) and 9973 K (P = 0.002). Font size also had a significant impact, with font size 9 pt producing more errors than sizes 11 and 13. No significant effect was observed for font type. Subjectively, except for irritability, other variables, including adequacy of amount and color of illumination, light distribution, pleasantness, performance, and sleepiness, did not exhibit significant differences among the various lighting conditions.

Conclusion: The findings highlight the importance of optimizing lighting conditions and typographic characteristics in reducing readability errors in medication prescriptions. However, further studies are necessary to determine the optimal lighting parameters and their interaction with typographic variables.