LED lights used to be very expensive. In the last decade the costs of LEDs have really dropped, and we can now buy them easily and inexpensively. LED lights are not coherent like lasers - the light from the average LED lights scatters and shines over a bigger area.

Philip Ball's article in The Guardian is terrific. It explains many complex aspects very clearly, especially amyloid and tau proteins and the history of different approaches to drug development.