Wow!” I said. “Is that a psychedelic light show?” I was at a party, and I could see a bright shimmer of purple across the room. It reminded me of my misspent rock-and-roll youth. My wife looked at me quizzically. “There’s no light show; it’s just a light,” she said. I looked at it hard and could tell she was right. So what did I see?

I didn’t know it, but I had entered the unsettling sphere of retinal detachment, a Twilight Zone where you can’t believe your eyes. And as I had yet to learn, recognising the symptoms of a displacement of the light-sensitive tissue lining the eye could mean the difference between saving and losing your sight.

In the weeks that followed, I saw more flashes of light that I knew weren’t there. I saw growing numbers of “floaters,” odd shapes that drifted across my field of vision. Once, while washing dishes, I panicked at the sight of a swarm of them congregating around a basket of bananas. Surprise! My floaters were actually fruitflies.

When I got worried enough to visit my eye doctor, he told me my eye tricks might signal a developing tear or detachment of the retina, the layer of cells that receives images and sends them to the brain via the optic nerve. If you see something like a curtain crossing your vision from any direction, he warned, come in right away.

Three days later, I saw the dreaded curtain, rising from the bottom of my right eye’s visual field. I went to the George Washington University Ambulatory Care Center, where retinal specialist Fadi Nasrallah put me on the retinal fast track.

... contd.