I’m constantly amazed how each patient I see interprets their vision differently. Clarity that may be more than adequate for one person isn’t even close to adequate for another. And aside from engineers, I never know how each person is going to react to asking “which is better, one or two?”
I think most eye doctors who refract all day long begin to judge just what change in a prescription is enough to affect someones vision. We have to do this to keep up with our schedules and because we are, after all, the experts.
But there is no way to account for each person’s interpretation of the world. When I think a patient may benefit from a tiny change in prescription, I will hold a lens up in front of them to gauge their reaction. If it’s significant for them, even if I think it won’t be, then I know it’s worth changing. I then usually finish the conversation with “…this is the smallest possible change we can make, and it’s almost within the margin of error of making a lens.”
It seems that prescriptions, visual interpretation and personalities are linked.
The engineer I mentioned above is usually nearsighted, and a very ‘critical observer.’ Any change to make their vision even the slightest hair better, they will grab onto and never let go of.
On the opposite end of the spectrum is a completely laid back ‘Type B’ person who may come in reading 20/30 on the chart but be completely happy with that level of vision. I can show them till I’m blue in the face how much better their vision could be, but they never listen. They know their vision is good enough for them.
Of course most people are somewhere in between. And I never know how critical they are about their vision. I just do my best with each patient to get them to see as well as possible.
During an exam most of my patients ask me if their prescription has changed and if they need to change their glasses. A lot of times the answer isn’t concrete. I make sure to show them the difference, from one-to-two, but often times I can’t judge whether or not that change is significant for them.
Glasses cost hundreds of dollars, and if yours work and the improvement isn’t perceived to be worth the time and money when you have a perfectly good pair of glasses already, then changing them is not advisable.
And I can only supply the information, then give my recommendations. I cannot decide what the world looks like through their eyes.