Our OCT arrived yesterday (I keep calling it “my OCT” but I should really stop that).  In the run up to its delivery, my colleagues and I started taking a note of patients who would benefit from having a scan, so we could ask them back as soon as the OCT arrived.  I was worried that we wouldn’t see anything interesting for a while – boy, was I wrong.

The machine arrived at 9.30am and the setup was faster than I had anticipated so we were able to do scans from 10.30am onwards.  It was funny since the first patient in the morning was a diabetic without retinopathy but with reduced vision.  I was moaning about how great it would’ve been to do a disc and macular scan*.

Anyway, the next patient was a middle aged electrician who told me that 20 years ago, he had an insect bite in his eye which had left a scar.  Of course, I assumed it was a corneal scar he was talking about but no, in his left eye, between his disc and macula (and then up a bit), there was a very strange looking area.  It was not raised on Volk.  It didn’t look like toxo… what was it?

Well, the OCT was almost up and running so I asked the patient to stay a while longer so we could have something interesting to look at for our first ever OCT scan.  While his glasses were being glazed, we discovered there was no RPE in that area of his retina.  It wasn’t damaged or moved up, it was just… missing.  The OCT tech and I were both stumped. Maybe it was a retinal manifestation of an electric shock? Who knows.

The patient was chuffed at his apparent uniqueness and left with a smile and two pairs of reading specs.

We saw some pretty interesting patients on Friday so I couldn’t have chosen a better day for the OCT to arrive.  We had an older gent with glaucoma and some very interesting floaters, a lady with a family history of glaucoma, another type 2 diabetic patient and a lady with a dense cataract.  While the tech was there, I was testing the limits of the machine.  I wanted to see the anterior angle, could I image the lens? What about the cornea? Topography? Vitreous?

The man with glaucoma was a new patient who needed a post cataract refraction (following bilateral phako).  He hadn’t had his eyes tested for over 15 years and had a really interested history which included cement getting into his left eye.  He’d recently been told to discontinue his glaucoma drops and discharged from HES.

Now, his disc scans were perfectly normal which was great but, well, here’s a video of his left eye:

We couldn’t do a scan through the entire vitreous but you could see the floaters by slightly misaligning the retinal scan.

After a busy (and stressful) day, I was quite happy for 5pm to roll around.  At 4.45pm, though, one of my patients from yesterday came in to pick up his specs.  I’d forgotten about him.  Oops.

On Thursday, I tested R for the first time.  He’d came in to us because he’d sat on his specs and not because of any issues he was having.  His last eye test was in 2010.  So far, so good.

I went through my usual history and symptoms and when I got to “Do you ever see flashing lights?”, he described an issue he’d had since he was 18: constant flashing, coloured (mainly green and yellow) lights in his central vision.  This affected both eyes and it made it difficult for him to read.  He described a central scotoma which, on Amsler, was small enough that he could still see most of the central dot.  When reading, he found himself unable to see the letter right in the middle of his vision, instead employing eccentric fixation but… he was 6/6 and N5 corrected in both eyes.

It was a bit of a mystery.  His maculae looked perfect on Volk and visual stress didn’t fit with his symptoms.

I hope you have a question in mind by this time.  What happened when he was 18? He was pretty specific: it started when he was 18: not twenty years ago, not a long time.  At 18.

Well, nothing apparently.  He couldn’t think of anything that would’ve caused it.

I told him that his vision was good but that his symptoms were unusual and I wanted to get to the bottom of them.  Luckily enough, I had a machine arriving the next day that could scan through the layers of the retina so we could see if there was something there, even if it was invisible to the naked eye.  He seemed really pleased that I was taking him seriously and asked when he should pop in to get the scan done.  Ever the optimist, I said after 4.30pm as we’d definitely have the OCT up and running by that time.

So, after an exhausting day, here was R.  We’d turned the prescreening area off so I had to nip through and quickly boot the OCT up while L got R’s new glasses fitted.  When we went through to the machine, I gave him a quick rundown of how it worked.  At that point, he started looking a little sheepish.

“I haven’t been straight with you,” he said.

“About what?”

“About what happened when I was 18… I used to abuse solvents and then I would stare at the sun.  I’m off that stuff but it’s obviously damaged my eyes.”

So, here we have solar retinopathy:

solar-ret

What you see is a focal disruption in the inner segment-outer segment photoreceptor junction.

It reminded me of a screencap I’d taken from BBC iPlayer that showed an OCT of a young boy who had a laser pointer shone in one eye:

ipler.png

I reassured R that his vision was good and that he’d obviously adapted well to his central scotoma.  I also thanked him for being honest – who hasn’t done something stupid when they were young?**

What a day.

 

* I’m hoping to do some in practice research on the retinal nerve fibre layer in type 2 diabetic patients.  I’ve applied to the College for one of their grants – it’s been a bit of a whirlwind so more on that later.

** Although my level of stupidity was boiling milk in a kettle – admittedly, I’ve lead a pretty sheltered life.

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