Why do I need an an eye exam if I have 20/20 vision?
Why do we always ask to dilate your eyes? Is it really necessary?
A colleague recently shared the results of a patient he saw– the report is as follows:
A 33 year old female reports to his office for her first ever eye exam. Her only complaint is that she has had a small spot in her vision for the last few months. The exam goes as expected– 20/20 vision in both eyes with a minimal prescription. The exam progresses until he starts to look at her retina and this is what he saw:
No pain. No double vision. No blur. No flashes of light. No headaches. No glasses necessary.
This is a tumor. Not only is it sight/eye threatening, but very likely has metastasized to other parts of her body.
Why was she still able to see 20/20 with this large mass? The macula, the part of the eye that determines how clearly we see, was not affected. The macula makes up ~1% of the retina… only 1%!! There is still 99% that can have diseases and not affect our ability to see.
Would this have been missed if she was not dilated? In this instance, likely not. However, this disease can happen in ANY part of the retina, meaning if it were any further away from the optic nerve it likely would not have been detected without dilation.