The second among the 12 pairs of cranial nerves is the optic nerve. Mary sat across the table from me in my office in a flowery dress with a print of bougainvillea on it. A matching hairband completed the outfit. “I have been unable to see clearly for the past few weeks,” she told me, continuing with a slightly more detailed description of her diminution in vision. “It is mostly on the sides—I am bumping into chairs in the house, and when I cross the road, I can’t see cars until they’re really close. I am afraid this might escalate into something serious,” she said, justifying her concern.
She was a teacher who was failing to call on kids at the extreme corners of her classroom. I would have loved to be in that class, I thought to myself.
Her astute ophthalmologist had confirmed that as there was no issue with her eyes, it was probably the optic nerves that were the problem and had ordered an MRI.
Optic nerve issues can often be misdiagnosed by ophthalmologists when presented with a patient who has a bit of a cataract; the real issue comes to light when they find that vision doesn’t improve after eye surgery. The MRI, expectedly, showed a tumour arising from the pituitary gland and pressing against the optic nerves. Those nerves, usually sleek white highways of vision, now resembled two elevated white lines on a speed breaker.
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“The optic nerves are a pair of delicate, white structures that carry visual information from the eyes to the brain,” I explained. “They emerge from the back of each eye, passing through small openings in the skull called the optic canals. These nerves then converge at a point called the optic chiasm, where some of the nerve fibres from each eye cross over to the opposite side of the brain. This crossing ensures that both sides of the brain receive visual information from both eyes, which is crucial for depth perception and binocular vision. And because this crossing is being pushed up by the tumour, the view on either side of your visual field is compromised,” I explained. “Too technical?” I asked. She nodded. I drew a diagram. She understood. “Surgery is the only option to remove it and relieve pressure from the nerves. It’s flattening the speed breaker from below the road, and for that, we’ll have to go through your nose,” I said, pointing a finger at mine to demonstrate what I meant.
A few days later, we entered her cavernous nostrils, navigating all the bumps along the way to drill the saucer-shaped piece of bone on which the pituitary gland rests. As we cut into tumour, it oozed out like cream cheese from a pastry. We meticulously inspected the cavity for any remnant of tumour, scraping the edges of the pastry as well. The optic nerve could be seen in the distance separated by a flapping spider web-like layer, relaxing peacefully.
“This is nothing short of magic!” she told me after surgery, once her vision was restored to normal. “She even saw Jesus for a few minutes,” the husband joked with me, when I went for my evening rounds. “We have opened up her third eye also,” I kidded, “so you’d better be extra careful now!”
Could it be that ancient eyes, unburdened by our modern lens, perceived a deeper harmony between the microcosm of our nervous system and the macrocosm of the spiritual world? Perhaps the very act of seeing, through the lens of the optic nerve, was once understood as a glimpse into the realm of enlightenment. Mary was delighted that her vision was back. The students sitting in the corners of her classroom weren’t.
The author is consultant neurosurgeon at Wockhardt Hospital, Mumbai.
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