I’m going to lapse back into being a physicist for a while: this post is about the signal to noise ratio during the eye test (and the OSCEs).

We all come with a certain amount of noise (background noise, like a 50Hz static hum) that sometimes drowns out what we are really trying to say.  As optoms, we have to try to filter out the noise (sometimes this involves steering the patient back onto Hx & Sx, away from their wonderful Michael Buble story) to get to the real problem.

Some patients have bombarded me with information.  They come in, sit down and just start telling me everything.  I must have a friendly face.  I still find it difficult to steer them back on topic, especially the ones who don’t seem to draw breath while they are describing their new great grandchildren or, in one memorable case, telling me about competing for World’s Strongest Man.  Actually, I take that back – I’m guilty of letting the World’s Strongest Man story go on too long because I love that sort of thing and I had many, many questions!

Others, you have to question carefully.  They will pause before saying “no” to flashing lights and that pause is very telling.  “Is it something you’ve experience before?” “Yes, but I’m not worried about it.  I’m not even sure that I saw it…” and then goes on to describe symptoms of a classic PVD.

I like to think that I’m now quite good at filtering.  I wasn’t at the start of pre-reg.  In the beginning, I attached significance to every little symptom.  Now, I have a few questions that I ask as a follow up to try and judge their significance: “when does it happen?”, “have you always had this?” and “any recent increases?”

I’m not too worried about a coloured flash of light in the periphery that lasted 20 mins and happened a year ago.  It doesn’t matter that a patient always sees floaters when looking at their white ceiling when they wake up every morning, just as long as they have always been there.  I’ve also become good at spotting eye-related headaches (I tend to use the LOFTSEA approach for headaches, which usually tells you if it’s something to be worried about or not).  Oh, and LOFTSEA works really well on malingering children and helps to separate them from those who are really suffering from sore heads.

I think the goal is to have a logical sequence of questions for common problems but, instead of treating it like a script, we try and make it a conversation.  If someone has, for example, severe headaches, they will feel we are really listening if we ask questions.

I went to my optician (a well known high street multiple) a couple of summers ago.  I was getting headaches in the afternoons and my distance vision was a bit blurry.  Now I have some mild BV issues (a 6D SOP and a 2D fixation disparity, which breaks down when I’m tired or reading for a while – it doesn’t help that I’m myopic) but I thought that the main problem was my prescription.  Like a good optom student, I had went to the clinic one day and refracted myself.  Anyway, I went for my appointment and as I sat in the chair, the optom said, “I hear you are having ‘headaches’.” She did air quotes around the “headaches” part.  You know, that made me really angry.  It was as if she thought I was lying.  She didn’t ask me about the headaches or ask any BV related questions and, in the end, just increased my contact lens prescription.  I was livid.  Also, the store put that 10 minute appointment down as a full eye test so when I called for my actual 2 year one, I was told that I wasn’t entitled to it because I had already had a full test 6 months before.  Rant over.

So, basically, even if the headaches are caused by dehydration or if they seem to be tension related, by talking about them and addressing them at the end of the eye test, the patient really feels as if they have been heard and that their symptoms matter.  Just try to avoid air quotes.

Now, I’m going to talk about the OSCEs.  Obviously I haven’t sat them yet (hopefully, I will in July this year) but I have had some OSCE practice during courses and I sat as a pretend patient for the pretend OSCEs at Caledonian University last year. Sitting as a pretend patient, I learned a lot about questioning.  Every pre-reg who came in had a slightly different style: many had a scattergun approach, some had a script that they followed, a few came in with their mind already made up and so only asked the questions that related to what they thought was going on (big mistake) and one or two had a logical approach that managed to filter out the noise and get to the real issue with minimum fuss.

I hope I’m not giving away too much but I was pretending to be a mother who had noticed her young daughter was rubbing her eyes a lot.  I had come to the optician to ask for advice.  Now, the pre-regs had 5 minutes to question me.  I could give out the information that was on my script and make up anything they asked that wasn’t pertinent (strangely enough, not one of the pre-regs asked me my pretend daughter’s name!).

I heard some weird and wacky theories about why this invisible girl was rubbing her eyes.  One pre-reg saw my glasses and immediately assumed that my daughter had poor eyesight and that was the cause of the rubbing (my blepharitis was flaring up that day so I wore glasses instead of contacts).  Given that the scenario wasn’t written about me (and, hell, I’m -2.00DS and I only started needing specs at 17 so assuming my fictional child would be shortsighted enough to be causing problems is a bit silly), my wearing glasses was part of the noise.  It was something to filter out.

Anyway, the best approach was from a pre-reg (PR) that I actually knew.  He came in, sat down and very politely got to the bottom of the problem in a couple of minutes.  His style of questioning followed the LOFTSEA approach in parts and I wanted to share it here.

PR: So, you’ve noticed your daughter is rubbing her eyes?

Me: Yes.

PR: Are her eyes quite red?

Me: They look quite pink but I don’t know if it’s because she’s been rubbing them.

PR: Have you noticed anything in her eyes? Any pus or are they watering?

Me: They water quite a bit.

(You could see him crossing off bacterial conjunctivitis in his head)

PR: Has she had a cold recently? Or anyone in nursery or at home had a cold?

Me: No, she’s been fine.  Everyone’s been fine.

(Crosses off viral conjunctivitis)

PR: Is there any particular time that it happens?

Me: I’m not sure. The nursery hasn’t mentioned it but I see her rubbing her eyes at home a lot.

PR: Is there anything else that you’ve noticed? Does she sneeze at all?

Me: Yes, she’s been sneezing quite a lot.

(He knows what it is but he’s not sure of the cause)

PR: When did this start?

Me: A few weeks ago.

(This took place in June last year so he needed to question further to see if it was hayfever or something else)

PR: Does she seem worse when she’s outside?

Me: No, in fact, her eyes don’t look as bad when she’s been out playing.

(Now, this is the question that NO-ONE ELSE ASKED and it’s the most important question you can ask for something like this, which has a specific time of onset)


(Caps for emphasis, he didn’t shout)

Me: Yes, in fact, we got a new puppy.

So, that was it.  He was one of only a couple who managed to get to the correct answer and he was, by far, the most logical in his questioning.

Now, I was at a course a few months ago and a similar scenario came up.  I wasn’t the one who was asking the questions so I sat and watched while the pre-reg who was stumbled her way through.  She didn’t even get close to the right answer.  The actor had thrown in a lot of noise and he was sitting playing with his phone, just to further throw her off.  When it came the end, she said it was bacterial conjunctivitis, even though he had said that he had noticed stingy white mucus (which is more in line with an allergy then bacterial conjunctivitis) and the time-frame was all off (the issue had lasted two weeks, whereas bacterial conjunctivitis tends to clear up in about a week).  I think the other thing that threw people off was the fact he said his daughter was having the same problems.  He also gave one big clue – he was fine during the day when he was at work, his symptoms only started when he was watching TV at home in the evening.

The two tutors on the course went around our group of pre-regs (there were six of us) and asked each of us for a diagnosis.  Everyone said bacterial conjunctivitis.  I was last, as always.  Buoyed by the fact I already knew the answer, I had a Columbo moment.

“Can I ask a question?”

“Yes,” the tutor said.

“Just one more thing,” I said, “what changed in your household two weeks ago?”

“We got a kitten for my daughter’s birthday.”

“You are allergic to the cat and there’s a good chance your daughter is too.”

That was the drop the mic and walk off stage bit for me.  I’m sure the people on these courses dislike me because I don’t realise I’m showing off until much, much later on.  Usually someone has to tell me.  So, if I’m on a course with you, I apologise in advance.

What I’ve learned from OSCE practise is not to overthink things.  If someone hands you a piece of paper with lots of information on it but IOPs are missing, there’s a good chance it’s not OHT or glaucoma.  If a photo of the back of someone’s eye looks normal then it probably is – don’t spend ages looking for reasons that it’s there – it’s just part of the noise.  In practice, we are bombarded with information and they want to do the same in the OSCEs.  They want us to be able to zoom in on the important parts.

At uni, I was told that if someone hands you a visual field plot, the first thing you do is to ask for the other eye.  The assessors are on to this, by the way.  At my last visit, I got handed an Esterman plot and I immediately, without thinking, asked for the other eye.  It was a binocular plot.  Sometimes the noise we have to filter out is noise that we’ve created or internalised from somewhere else.