Take off your mask

Underwater you can’t really hear anything. Sound is muffled and communication between people occurs via very basic underwater sign language. Vision is everything. It’s the only one of the five senses that matters. Taste is reduced to a mélange of salt of the sea and the rubber of the breathing hose. Smell is impossible. The only thing you can feel is the motion of the water and the contours of your scuba gear. “Take off your mask,” my instructor signed to me. We were 13 metres below the surface, where the water pressure is more than twice that of the air on land, and I was being instructed to take off my diving mask and expose my eyes to the underwater elements. I would be “blinded” until I could reposition the mask on my face and clear the water out with my breath. I don’t even like opening my eyes underwater in a swimming pool. I knew that the pressurised, salty water would sting my eyes and rush into my nose and then my throat, producing a choking, drowning sensation. But I had to do it. This crazy manoeuvre was just one of those required for the open-water scuba diving certification course in which we had enrolled. I pulled the mask off quickly, holding it tight so I wouldn’t lose it before I could put it back on, clear the water and reopen my eyes. I was diving with three friends and a scuba instructor in the Red Sea, where we had arrived in a shiny red speedboat earlier that morning. The moment we dove in, four curious dolphins had come to investigate. They were close enough to reach out and touch, and they lingered long enough for us to make eye contact before they went on their smiling, merry way. Scuba diving was our backup plan. We had come to Egypt to kite surf in the shallow, wind-swept lagoons close to shore. Kite surfing is a high-speed sport that harnesses the wind to let you glide across the surface of the water like a racing yacht. Its quick movements and exposure to the sun, surf, sand and shore, with loud wind in your ears, constitute a sort of sensory overload that might be considered addictive. But there was no wind for a few days, so we entered the alternate, silent, slow-motion world of scuba instead. Without vision, a scuba diver is completely handicapped, and as I replaced my mask and forced the water out by blowing air through my nose, I felt a tiny sliver of the relief that patients must experience after successful surgery for serious bilateral disease. Some bilateral disease is relatively straightforward to treat. Consider the occasional patient who comes to your office with cataracts that have reduced vision to counting fingers in both eyes. Or the less fortunate but still perfectly treatable patients with Fuchs’ endothelial dystrophy. Bilateral macular holes pose a more difficult challenge; operating on both eyes quickly can leave the patient with bilateral gas tamponade, which greatly inhibits their ability to function, but waiting too long to treat the second eye can lead to suboptimal results. Others, however, are vastly more challenging: although severe diabetic retinopathy has become much less common, patients still occasionally present with bilateral vitreous haemorrhage or, even worse, tractional retinal detachments due to proliferative disease. For some, however, there is no cure yet, such as the unlucky souls with degenerative genetic disease of the optic nerve or retina. I was very happy to regain my vision as soon as I had cleared the salty water from inside the mask. But my eyes continued to sting, and I wondered how long it would take for them to recover. Seeing my diving buddies struggling with the same problem made me feel better, and, having finished the other required tasks, like simulating the loss of the breathing tube and sharing a spare tube with a buddy whose tank has run out, we swam off to enjoy a few minutes of freedom before we had to surface to get ready for the next training session. As I circled a spectacular coral reef, I wondered whether scuba diving might be something that the visually impaired might enjoy. Although I am a wildlife enthusiast and have probably seen every nature video that the naturalist David Attenborough has ever made, I don’t dive for the excitement of coming eye-to-eye with a dolphin or watching tuna dart past me at what seems like the speed of light. These are simply enjoyable extras. Instead, I dive to experience the sensation of lightness and the feeling of serenity, for the complete peace of mind that only tropical fish seem able to enjoy. I dive for the silence and the flow and the freedom of movement that weightlessness affords. And so I closed my eyes and swam. Dr Leigh Spielberg is a vitreoretinal and cataract surgeon at Ghent University, Belgium

Tags: underwater blindness