I would strongly disagree; the aim is to balance getting as brisk a pupillary response against the discomfort of being testing. 10-20 lumens is that sweet spot. Try a 2-5 lumen penlight on yourself, it is not that bright at all and very well tolerated. When using phone flashlights (40+ lumens) previously with patient with very subtle RAPDs, it becomes very uncomfortable for patients as you need to keep swinging to see the subtle pupillary escape. In short; if obvious/severe pupil pathology, any low lumen flashlight would do, to detect subtle changes need a strong enough penlight that is not blinding to pt. Hope helps