Tooth shade determination plays a critical role in the overall success of dental restorations, yet visual impairment can negatively affect its accuracy. The objective of this cross-sectional clinical study was to evaluate the potential impact of visual impairment on shade selection by employing two distinct approaches: spectrophotometry and conventional shade guides. The study sample comprised 2796 maxillary and mandibular teeth. Shade selection was assessed subjectively using a shade guide (VITA Classic, VITA Zahnfabrik) and objectively with a spectrophotometer (VITA Easyshade® V, VITA Zahnfabrik, Bad Säckingen, Germany). For each tooth, three separate measurements were recorded, allowing a 15 min interval between consecutive samples. Comparisons of shade selection were made between observers exhibiting normal vision and those with myopia, astigmatism, or hyperopia. Findings revealed that myopic observers perceived the lower central incisors (2.63, P < 0.05), upper lateral incisors (2.42, P < 0.05), lower lateral incisors (2.34, P < 0.05), and lower canines (2.64, P < 0.05) with greater clarity. In addition, non-astigmatic subjects rated the lower second premolar as lighter compared with astigmatic subjects (−2.01, P < 0.05). Individuals with myopia tend to perceive teeth more clearly; however, no significant differences were observed among those with astigmatism or hyperopia.
