This patient said his floaters were multiple, tiny,
moving specks in both eyes. A thorough examination
was done and no floaters were found.
went over his symptoms again, and I wondered if he could possibly be seeing his
own retinal white blood cells, instead of seeing floaters.
A few years previously I had designed a device that let patients see their own white blood cells. The device was held in front of the eye, and the slit lamp light was then shown through the device and into the patient's eye. This device was manufactured commercially and sold as the Karickhoff Flying Corpuscle Viewer. It was a unique modification of the blue field entoptic test. When this patient was tested with the device, he said he
saw his “floaters” very distinctly. So, he
actually was seeing his own retinal white blood cells and thinking they were floaters.
You, too, can see your own white blood cells by looking at the bright blue sky. If you notice closely, you will see that your white blood cells move every time your heart beats. These white blood cells are located in the blood vessels just slightly peripheral to the center of your vision.
This Flying Corpuscle test has great value. Let's say a cataract patient can not see the "E" chart, and the doctor can not see the back of his eye due to the cataract. The question is, "Why can't the patient see the "E" chart?" Is it because of the cataract or because his retina is abnormal? If one shines the light through the Karickhoff Flying Corpuscle Viewer and the patient sees his own tiny white blood cells, then you know his retina is normal although you can not see it. If he can not see the corpusles, he will not get good vision even if the cataract is removed because his retina is abnormal.