Itâs Not the Needle That Hurts. I believe the pain is due to the solution used to clean the eye prior to the injection and not the needle itself. The solution is called âBetadineâ and is commonly used to cleanse the eye prior to intraocular injection. Most retina specialists use this a part of their routine.
For numerical convenience, an object brighter than 0th magnitude has a negative magnitude; the brightest star, Sirius is magnitude -1.4; the full moon is magnitude -13, and the Sun is a blazing -26th magnitude.
For absolute magnitude, a difference of 1.0 in magnitude corresponds to a ratio of 2.512 â 10 0.4 of absolute brightness. The Milky Way, for example, has an absolute magnitude of about â20.5, so a quasar with an absolute magnitude of â25.5 is 100 times brighter than the Milky Way.