Uehara, Miyako

上原都

Miyako goes by the nickname "Study-Bug," a title she earned from her constant studying and deeply dislikes, despite her grades being nearly average. She frequently becomes angry when she cannot study because of the chaotic situations she is often forced into against her will. In episode 16, Miyako was even handcuffed to Sayaka Suzuki to compel her to track down Ichijou.
She possesses a strange trait that led others to give her another nickname, Deko, meaning "convex surface," due to her exceptionally large and shiny forehead, which grows more extreme with each episode. It begins with a simple sheen in the first episode; in the second, it turns into a blinding flash; by the third, others can actually style their hair using the reflection on her forehead. In a later episode, her forehead becomes so bright that other characters are forced to wear welding masks just to look at her. Additionally, she apparently has ESP. During some of the series' more intense events, she always attempts to stay calm, though she cannot always achieve this through willpower alone.
She is not always seen wearing glasses, as she also uses contact lenses. In episode 4 of the anime, she explained that after long hours of studying, it is much easier on her eyes to wear glasses rather than contacts.
-Wikipedia