"...we'll take the launch down to the Thames Barrier. You've never seen it after dark."
"I havent seen it at all. Won't it be cold?"
"Not particularly. Wear something warm. I'll bring a thermos of soup and the wine. It really is worth seeing, Declan, those great hoods rising out of the dark river towering over you. Do come. We could put in at Greenwich for a pub meal."
(P.D. James - Original Sin)
Runner's can be inclined to dithering. Once they are out of the house, that's different. But when I have my long run to do, boy!, I can dither. I need to eat at the right time. I need to drink the right amount (too little and I won't last the 12 miles, too much and I'll be stopping to ...). Shall I take music? What kind? Which earphones? What will I wear? How will I keep my iPod dry if it rains? (ans. cling film) Will I need my Oyster Card? What about a £20 note? Which shoes? I am going to stop there, as I could go on for several hundred more words. Anyway, the last question that I always ask is: 'Oh, where am I going to go?' 12 miles (as it was in this case) is a lot of pavement to eat up, and if you're going out for a couple of hours, you may as well go somewhere nice. In South-East London we are not spoiled for nice open spaces.
I always end up orbiting Blackheath in some way. So after there, I wandered towards Greenwich, and with several miles still to use, headed for the Thames Path. When I hit the path on the South side of the river, I usually go east because it's quieter, and because of the Thames Barrier. There is something about it that I love. It is beautiful. It doesn't look like a flood barrier at all, more like an oversized Christmas decoration left to float. Once you turn south on the Greenwich peninsula it comes into view in the distance and every shuffling step brings you closer and closer, and it just gets bigger and bigger.
I think the other reason that I like the Thames Path is the constant motion in one's eyeline. Years ago, when LCD computer screens first began shrinking (and so expanding the real-estate of our desks), there was the problem of the dead-pixel. LCDs use the light-modulating properties of liquid crystals that behave in certain ways when tiny amounts of electricity are run through them. In the earlier days of LCD displays, it was common to have a couple of dead or stuck pixels on your screen. If you were lucky, you could gently massage them back to life - a carefully-applied fingernail, a little gentle rub, and a pixel stuck in the 'off' position might come back to life.
When I'm running, I feel like this is what is happening to my retinas. In the urban landscape, almost everything is static; the pixels are stuck in the 'grey' position. Features of the landscape are more difficult to notice because they don't move. This is what is so amazing for me about the Thames Path, on one side, there are cranes, fences, the giraffe-heads of CCTV cameras peering from out of their pens, the Dome, the Barrier. Everything is statue still.
And on the other side, is the broad Thames with its million wavelets. There is something restful about seeing this movement, like my eyes are getting a workout, a long and deep yogic stretch that they can't get in the town. And so it seems that movement is the essence of vision. We have a highly adapted flicker fusion frequency of about '60'. This means that we can see at approximately '60 frames per second'. Urban landscapes are discordant with our wellbeing in ways that we don't yet understand, but it seems to make some sense to me that my eyes feel restored, somehow, by this omnimovement of the Thames. It is as close as they can get to experiencing the dynamism and fluidity of the paleolithic landscapes of the past. Those are the landscapes, after all, the eye evolved to see.
(Many studies have linked the modern pandemic of myopia with too much time spent indoors looking at books or screens. See, Nina Jacobsen, Hanne Jensen, Ernst Goldschmidt, ‘Does the Level of Physical Activity in University Students Influence Development and Progression of Myopia?—A 2-Year Prospective Cohort Study’, Investigative Ophthalmology and Visual Science, April 2008, 49:4, pp. 1322-7.)