How to diagnose Cone dystrophy ?
How is cone dystrophy diagnosed? The diagnosis of cone dystrophy is made based upon the presence of characteristic symptoms, a detailed family history, a thorough clinical evaluation and a number of supporting tests. While exams that measure visual acuity, perception of color, and field of vision are used to arrive at a proper diagnosis, an electroretinogram (ERG) is used to confirm the diagnosis. During an ERG, eye drops are used to numb the eye before a special contact lens recorder is placed on the eye. Then a series of flashes of light are used to stimulate the retina. Doctors can then measure the electrical response of the rods and cones to the light. The test is performed twice  once in  bright room and again in a dark room. A weak of absent signal of cone cells indicates cone dystrophy. More details about the diagnosis of cone dystrophy can be accessed through the University of Michigan Kellogg Eye Center.