Welcome to question of the day #293

Welcome to question of the day #293

I’ve been working as an eye specialist for a year but am still worried about missing something and making the wrong diagnosis. Do you have any tips?

I’ve been qualified for 31 years and am still worried about missing something and making the wrong diagnosis.

Let me try and help you by sharing some of my recent learning.

I was asked for an opinion as an expert witness on a case involving a male patient in his mid-twenties who went for a routine eye examination in community practice. He had a mild cataract in his right eye, 0.30 cup-to-disc ratio in his right eye, and 0.7 in his left eye. His right and left best corrected visual acuities were 6/5. His intraocular pressures were equal and in the normal range and his visual fields were full. He was rightly referred to an ophthalmologist for further investigation.

Unfortunately, he did not receive the appointment information and was not examined. A year later he attended the eye emergency room with a catastrophic loss of vision in his left eye which he had suddenly noticed. He was diagnosed with primary open-angle glaucoma and placed on appropriate eye medication.

I was asked if his eye examination in community practice met the expected standard. I took it that he had primary open angle glaucoma as this is what he had been diagnosed with and framed my report around that diagnosis.

Fortunately, an expert ophthalmologist was asked for an opinion on the case and he requested that the patient undergo an MRI scan of his head. I thought this was odd at the time but he was correct to do so. The MRI scan showed optic neuritis in the left eye. The patient did not have primary open-angle glaucoma. Or any other type of glaucoma.

When I reviewed all the clinical information for the left eye it was obvious that the sudden and catastrophic loss of vision in the left eye did not fit with a diagnosis of primary open-angle glaucoma. I had ignored this piece of clinical information because it did not fit with the diagnosis. The sudden and catastrophic loss of vision in the left eye fits perfectly with a diagnosis of left-eye optic neuritis. The high cup-to-disc ratio in the left eye and the asymmetry in cup-to-disc ratios between the eyes is often a sign of glaucoma but [as I learned here] not always.

My learnings were:

Don’t assume that hospital-based eye specialists have made the correct diagnosis.

Consider all the clinical information.

Don’t ignore information that does not fit a diagnosis.

So, now when I’m receiving a diagnosis from someone else I consider all the clinical information and see if everything fits the diagnosis.

When I’m making a diagnosis, I consider all the clinical information I have gathered. I think about whether I need to gather any more information. Then I make a diagnosis. If I can’t, I send the patient to someone with more equipment/skill/knowledge than me.