What To Expect When You Have An ERG: The Vision Diaries
To read part three first, click here.
I was sent to a large hospital in the big city for an ERG – an electroretinogram test on my vision – to confirm my diagnosis of AZOOR and to find out exactly what I see. I wish I hadn’t Googled it beforehand and I wish that there had been this exact blog post to read before I went to the hospital that day, just so I would have known what to expect!
An ERG measures the electrical response that the cells in the back of your eyes have to light. A neuro-opthamologist shows you a series of patterns and flashing lights and all you have to do is look at a big screen.. Sounds simple? You would be quite mistaken.
I went into the hospital and met with a health care technician, who did a series of basic eye tests with me and it was really good, despite the dilating drops (which I’m actually getting used to at this point!) and the fact that I struggle with colour blindness tests now that I’m missing quite a lot from my visual field in my right eye. These tests felt like every other eye hospital or opticians visit and I felt completely comfortable.
The next part of the test was the bit I was dreading.
I had read on Google (why do we do this to ourselves?!) that my eyes would be clamped open and a wire attached to my eyeball with a little pad, whilst I would be asked to look at some patterns on a screen. This definitely doesn’t happen.
Firstly, the technician cleaned the make up off my face next to my eyes, on the bridge of my nose and on my forehead. I obviously wasn’t wearing any eye make up to an appointment for my eyes anyway. She then attached little sensor pads to different locations all over my head and around my eye area. Then came the one bit of the whole appointment that I was absolutely dreading, the wire on my eyeball. The wire was attached with a pad to the bridge of my nose, then threaded across my bottom eyelid against my eye, and then attached to the skin next to the outer corners of my eye. It actually wasn’t as bad as I thought. It felt like I had a bit of a hair or an eyelash in my eye.
The technician pulled a big computer screen in front of my eyes and told me to watch a series of flashing hexagonal shapes and told me to not blink. She said the tests would last around 30 seconds at time.
It is absolutely impossible to focus your eyes for 30 seconds and to not blink. I don’t know anyone who can hold their eyes open and focus on some images for half a minute at a time!
I did my best, even though the technician was clearly frustrated at me blinking every 6 seconds – I think my body was just trying to evacuate the wire from my bottom eyelid! – and eventually we got through the test. I then had to look at a series of flashing lights. I didn’t have to say anything or press any buttons like a normal field test, I just had to sit and watch. I was then left in a dark room for 20 minutes, before some of the tests repeated with the flashing lights.
That was it. I was in the hospital for about three hours in total, but I imagine this would have been quicker had I not blinked a thousand times whilst the technician was doing the test.
These images, or maps of my vision, that were produced from these tests were then sent to a specialist to be analysed and did confirm my diagnosis of AZOOR. The tests could show the doctors exactly what I can see, which was amazing, because it’s very hard to describe to someone what you can or can’t see.
Then I decided to take control.
To read the whole series, please click here.
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