"Don't read so much, you'll damage your eyes," warned my grandma. Now, at the age of 40, I have to admit that when I'm tired, I can no longer see clearly when I'm reading. I'm also starting to notice that I have to hold my children's school photos further and further away to recognise them. What's happening to me?

Every optician will shout: "You need glasses!" But I also know what the optician needs, namely a shop. So I ask somewhere else first.

 No glasses at all

I ask my grand-cousin, a respected ophthalmologist, whether I should wear glasses. Her answer speaks volumes: "If you start wearing glasses, it's all downhill from there. The eye gets lazy. Think about it carefully." Interesting saying, just between you and me. I wonder if other people are given this advice by their ophthalmologists? (Perhaps I shouldn't have revealed the source.) So no dioptres on my old-fashioned eyes.

The reasons for age-related visual impairment

I do some research and come across sentences such as "visual impairment is a long-term consequence of diet and lifestyle" (it almost can't be and if it is, I can hardly reverse it), "deposited waste puts a strain on the eye" (cupping and scraping helps, see my book), and I often read the recommendation to "train the eye muscles". At some point, I come across the raster glasses in this context.

The glasses with the holes

Raster glasses are glasses with black plastic discs that are perforated with countless small holes. This has the effect of training the eye. You do this intuitively too - squinting your eyes to see more clearly. The raster glasses do this for you and by limiting the incidence of light, a sharper image is created. They also promise to train your eye muscles, improving your vision in general and in the long term. They should be worn for 10 to 30 minutes a day, preferably while reading or working at a PC. This gradually trains the eye muscles and improves your vision.

And what should we believe now?

That sounds great, of course. If it weren't for all the criticism and doubts about the effectiveness of these glasses. None of this has been scientifically proven. On the other hand, what can be scientifically proven that would destroy an entire industry? Visual impairment is a huge business that cannot be ruined with cheap plastic glasses. So I'm looking for testimonials, and any of you are welcome to look at them on Amazon, for example. The glasses are rated very favourably across the board. All I can say is, yes, you can see clearly. When I'm tired and want to finish the film, I put them on. I can still see clearly for quite a while after taking the glasses off, which somehow feels incredible. Other people also report a long-term improvement in vision. I personally can't judge that yet. I can only recommend that you read the reports. Good look!