Read this before you BBQ those expensive glasses!

July 1 - 15  |   Granted this story sounds far fetched... but it happened this week!  The complex coatings that are applied to most modern eyeglass lenses do a great job of protecting your lenses against scratches and glare... but they are not heat proof!  This past weekend, a patient opening a hot BBQ to peak in at his steaks got a nice blast of heat to the face.  The heat cracked (crazed) his lenses instantly.  Crazing of the coatings makes a lens look like shattered glass and obviously causes poor vision.  It happens because the intense heat causes expansion of the coating materials at a different rate from the underlying plastic.  Crazing your lenses makes for an expensive steak dinner as lenses need to be replaced!  Be careful when you open a hot oven or BBQ.   Happy Canada Day or Independence Day!   dr.j   PS - leaving your glasses in a hot car can do the same thing!