a realization about size of print and visual acuity

I realized recently riding the CTA rail line that my elderly vision acuity is affected by my unsophisticated educational preparation. I look at a piece of type on an advertisement. It has a particular size of print. My preparation causes me to respond to sizes I can read with the thought that these sizes are common and reasonable for anyone to be viewing. It causes me to respond to sizes I cannot read with the thought that these sizes are uncommon and not reasonable for anyone to be viewing. This is a defensive preparation. It holds that whatever I perceive is proper if I can read it and improper if I can't. My more careful consideration of lthis matter leads me to the observation that at any time in my life there are certain sizes of print which I can read and certain ones which I cannot. From time to time the size which is discriminative in this way changes, getting larger over the long run. The automatic response, which I can now see is wrong, is that the discriminative size is a property of the environment rather than of my visual acuity. It would have been useful if the correct concept had been taught at the beginning of my education when I first began to look at print, including public print, with comprehension.