New (stronger) prescription makes no difference to my vision

A perplexing problem -- please can anyone advise?

I wear glasses. Had an eye test recently and the optometrist told me that my sight had deteriorated. This puzzled me because I thought my vision through my glasses was still perfectly good and hadn't deteriorated since the previous test (which was 3 years ago).

OLD prescription (3 years ago)
Right: Sph -3.00, Near-ADD +1.75
Left: Sph -2.75, Cyl -0.50, Axis 80.0, Near-ADD +1.75
Inter-ADD 12.00

NEW prescription (last week)
Right: Sph -3.25, Cyl -0.25, Axis 80.0, Near-ADD +2.25
Left: Sph -3.00, Cyl -0.50, Axis 80.0, Near-ADD +2.25

Now I have new glasses with lenses as per the new prescription but I can detect absolutely no difference. My vision through the old glasses was perfectly good, as I've said -- and so is my vision through the new glasses. The optometrist has checked the lenses in the new glasses to make sure that they conform to the new prescription.

Finding it all very odd, and would be really grateful for any comments.

Thanks very much . . .
A