At first, I think I must have misheard what the optician is telling me, because it’s something no one has ever said to me before.

“Sorry, what?” I say.

“Your distance vision has actually improved,” she says. The optician then goes on to explain that, in every other respect, my vision has deteriorated markedly.

I knew this day was coming: for at least a decade, I have been sliding my glasses down the bridge of my nose in order to read, a little lower every year. Recently, they’ve started to fall off. I have finally run out of nose.

“Where have you been?” my wife asks when I get home.

“At my eye test,” I say. “The optician says that I need bifocals.”

“Oh dear,” my wife says.

“She actually said varifocals,” I say. “Which are bifocals that cost 400 quid.”

“Can it wait until after we move?” my wife says. “We don’t have 400 quid.”

“No, it can’t,” I say. “That’s just for the lenses, by the way. Frames are extra.”

“Take this box down to the sitting room,” she says. “And don’t look in it.”

There isn’t much to see at home these days, anyway. The walls are covered in faint rectangular outlines where pictures used to hang. The shelves are too sparsely stacked for the remaining books to stay upright. Drawers are empty, cupboards bare. The middle one and the youngest one are asleep at midday on two sofas downstairs, because their beds were carted away while they were out.

My wife opens the door ahead of me, strides into the darkened sitting room and yanks up the blinds. The youngest one groans and pulls a duvet over his head – he’s been celebrating after finishing his last A-level. The middle one sits up, blinking and confused.

“Smells like teen spirit in here,” my wife says. “Time to get up.”

We have another three weeks of this: all five of us, camping in a half-furnished house. And then, who knows? After 25 years, a family home exerts a certain gravitational pull on its members, a force that might not be easily replicated in another, wholly unfamiliar spot. And it isn’t just a home: it’s a street, a neighbourhood, the pin in the middle of my mental map of everything. Where we’re headed is only a few miles away, but I do not, as yet, even know what bus to take to get there.

Shortly after we move, the children will scatter, heading off on summer excursions from which they may never fully return. I try not to think too much about the distant future – you never know if you’re even going to be invited – but in times of change, I find it helpful to focus on the immediately forthcoming. At this point, however, I can’t even see that far.

Two days later, I return to the optician, wearing contact lenses so I can try on some new frames. I squint at the prices, then look in the mirror, trying to imagine my eyes refracted behind two fat prisms. I try on a dozen pairs of varying shapes and shades. I don’t like any of them.

“I don’t know why I’m being fussy,” I say to the man behind the counter. “They’re still going to be bifocals.”

“Varifocals,” he says.

“Yeah,” I say. “And the glasses I’ve got are too strong, anyway. I guess it’s time to bite the bullet.”

“You could see how you get on with a slightly weaker prescription,” he says. “You would notice some improvement with reading.”

I look at him through lenseless horn-rims, a price tag resting against my cheek. “You mean, I could buy myself, like, another inch of nose?” I ask.

“That’s one way of looking at it,” he says.

“Another year of forestalling the inevitable,” I say. “Maybe two.”

“Hmmm,” he says.

I turn back to the mirror. Behind the glasses, my expression is inscrutable, and also a bit blurry. “I’m going to need to go away and think about this,” I say.

In truth, my mind is made up before the words are out of my mouth.