<prompt> Below is a common instrument used in ophthalmology. In order to view the entire retina what is the power of lens you would like to attach to the instrument90 D78 D-58 D20 D  <response>: Ans. d 20 DRef: Yanoff Ducker 4e, p. 89Instrument is indirect ophthalmoscope.Condensing lens commonly used is 20D biconvex lens.MagnificationPoweroflensPowerofeye 20D60D 3times 