Sight's slow slide to senility

Try saying that with your mouth full

About five years ago I went to get to my eyes tested. 'You're an old git', the optician said.

Actually, I'm lying. What he said was that I was starting to suffer from Presbyopia.

For the benefit of my Anglican relatives, this is not a new variant on Presbyterians (although I have to say that some Presbyterians may have Presbyopia).

Presbyopia is when the lens of the eye starts to stiffen up with old age, and can no longer achieve its full focal length. The result is that you can no longer focus on things close to and so have to start reading stuff at arms length.

Now, this doesn't happen overnight, and presbyopia is a finite condition - the lens only stiffens up so much. My optician told me that it would take about five years to make the transition from young and lovely (in optical terms) to old and senile, and in the meantime, would I like some new glasses.

Glasses cost a bit, and I was faced with the prospect of a new set of glasses to manage a changing eyesight over a period of five years, so I went for a pair that would take me through the transition period - a half way house between myopic and presbyopic - neither one thing or t'other, as the Northerners would say.

So, five years are up, and I've just gone for a new set of glasses. Because I'm already short sighted (the technical term being 'myopic') I need glasses for both distance and near vision.

This gives me two choices.

1) Get two sets of glasses. This is a disaster in the making. Not only do you have to keep on swapping glasses, but you also have to find somewhere to put the second set. I can just see myself leaving the house early in the morning wearing my reading glasses and I wouldn't know the difference because I'm always a bit bleary eyed and half asleep anyway and would just put the fuzziness down to that pint or ten I had the night before. Or else I would put the other pair in my back pocket and sit on them or leave them on the train or something.

So I went for choice 2). Varifocals. This is a cunning bit of science where you get the best of both worlds - the upper half of the glasses focus on long distance, the lower half focus on short distance and then there is a smooth transition of focus from one to the other.

It sound's good, doesn't it? - you can have your cake and eat it

Except it doesn't quite work out like that. The first inkling of what's going to happen is when you are called in to have a lesson from the optician on how to wear your new glasses.

No it isn't put them on and use them.

The secret is, apparently, 'Nose and chin'.

Before you start wondering about how the nose and chin get involved with the eyes, let me explain.

The problem arises because of the gradually changing nature of the focus from top to bottom and the fact that grinding techniques (when applied to glasses) are limited on the shape that glasses can be ground to.

This means that although the right focal shape can be ground into the central vertical strip of the glasses, the sides can't be ground to the right shape.

Put simply, as long as you look straight ahead you're OK, but if you look out the side of your glasses you're screwed.

Which is why nose and chin comes into it. 'Point your nose at the thing that you want to look at, then adjust your chin so that the item comes into focus'.

Great. Not only are my eyes senile, I'm going to look senile because I'll be nodding my head up and down trying to get into the right focus

And I bet that you've spotted some of the flaws in this already.

You see, (or in my case, move nose, then chin, then you see), you don't look straight ahead all the time.

The first flaw became apparent when I drove. I now find that although items that are ahead are in perfect focus, items to the side (like when you look out of the side of your eyes to see if any cars are overtaking) are out of focus. And looking in the rear view mirror? I've spent a lifetime developing the technique of keeping facing directly ahead and quickly glancing at the mirror to see if anyone is behind me. Now I've got to nose and chin. And you have to look down to look at the rear view side mirror, which is in the 'reading' focal bit. So what used to be a relaxing drive has turned into an exercise of neck yoga

Looking down when walking is even more fun. Look down at steps - great, now they're out of focus because I'm now looking out through the reading bit of my glasses. Nose and chin again.

In fact, I've discovered a secret.

Those old people you see shambling along the street muttering to themselves and nodding their heads?

They're shambling because they can't focus on what's in front of them, they're muttering 'nose and chin' to remind themselves of what they need to do to see their feet and they're nodding their heads just to get the right part of their d**n varifocals into focus

I'm off to get my Zimmer Frame