Why
do people suddenly go blind,” asked the unidentified voice on the phone? I
could discern a glint of anxiety in the voice.
I paused a little, not knowing
from where to commence my response. It was a straightforward question and the
answer also simple but explaining the nitty-gritty of the symptom on the phone
was quite complex.
I could immediately think of over 200 possible causes of sudden painless loss
of vision and another 100 causes of sudden painful loss of vision. Reeling out
these causes to the faceless person at the other end of the phone was
meaningless.
The
anxiety in his voice was a warning that this was not supposed to be a
teacher-student interaction. It meant there was someone with an urgent problem
requiring some crucial advice. So I decided to ask some searching questions.
“Sir,
do you have anyone in particular in mind?” I asked. “My 70-year-old aunt,” he
replied. “How sudden is ‘sudden’?” I questioned. In the over four decades of
practising medicine in this part of the world, I have learnt that several words
which are supposed to have definite meanings are used with such laxity that
they lose their significance.
“I
was in her house two weeks before and she opened the door for me. She cooked me
a really delicious meal without any assistance from anyone. Her housekeeper
came in later to tidy the table and wash the dishes. Then two days ago, she
phoned me that she had to grope, in broad day light, to find her way inside the
same house!” he said. “That’s a helpful piece of information,” I replied with
satisfaction. “’Sudden’ here might just be sudden,” I surmised.
“By
the way is she diabetic or hypertensive?” I asked again. “Not to my knowledge.
She has never been ill in the last five years!” he replied confidently. My task
was still very difficult even though through those questions I had already
excluded over two dozen possibilities! “You have to bring your aunt to my
office for examination and investigations,” I demanded.
The
following day, he breezed into my office with his aunt. “Doctor, your patient
is here,” said he, introducing his aunt. As she was led to the examination
chair, I had doubts if this was actually a case of sudden loss of vision. But
there was no need for guessing now since she was with me. Auntie could barely
see my hand waving very close to her face. I shone my torch on her eyes and was
greeted with a brisk wink in each eye by a nice round pupil in response to the
bright light. Now something else caught my attention! It was least expected,
yet common place. Behind each pupil was a whitish opacity.
“Cataract!”
I blurted out in disbelief. Cataract blindness is usually never sudden!
Blindness is typically gradually progressive. Could there be other co-existing
and more devastating disease in the eyes? I reviewed the information provided
earlier and conducted a few more tests.
Certainly,
Auntie had straightforward cataracts. Why then is her visual loss sudden? From
the evidence gleamed from the eye examination, the cataract in her left eye
started first. I estimated the near total visual loss in that eye had occurred
not less than two years before. She had been seeing through a small clear
window in the cataract in her right eye until a few days ago when it sealed up
plunging her into near total darkness.
This
is an unusual case! What then are the common causes of sudden painless loss of
vision? The commonest cause in this area is bleeding into the eye. It is not
infrequent in sicklers especially those with SC haemoglobin between the ages of
15 and 55 years.
Diabetes
and hypertension are some of the other causes of bleeding into the eye
that can also cause sudden loss of vision through several other
mechanisms. I remember seeing recently a young man who lost vision in both eyes
after ingestion of wood alcohol (Methyl Alcohol) and another who suffered the
same fate from quinine.
Sudden
painless loss of vision can be dramatic and alarming to both the patient and
the doctor. In some cases, immediate attention and diagnosis within a few
minutes after occurrence may determine if or not the eye will ever see again.
An accurate history is just as important as the clinical examination. Do not
hold anything back from your doctor including the history of recent or past
illnesses, medications, contraceptive use and drug abuse.
Source:
tribuneonlineng.
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