7 reasons why your pupils may be dilated

 Tricky Tasks
According to some studies, the harder your brain works, (for example when you're calculating a tricky equation) the more your pupils will enlarge. Furthermore, the more difficult you find the task, the wider your pupil will get. If you wanted others to think you find algebra a breeze, don't worry, your secret is most likely safe! Even if you found the task absolutely mind-boggling, this pupil dilation is barely noticeable with the changes generally less than half a millimetre. Your pupils will return to their normal size when you have finished or given up on the task.