Text and Data Mining valid from 2019-06-18
Received: 13 October 2018
Accepted: 30 April 2019
First Online: 18 June 2019
: Martin A. Mainster, PhD, MD, FRCOphth is a consultant for Ocular Instruments, Inc. which manufactures ophthalmoscopic lenses. The other authors declare that they have no competing interests.