I just had a patient come in complaining his single vision glasses were causing eyestrain and they had been re-made 4 times. I checked and his right lens was almost a half diopter too strong with waves in it. This was a -1.25 diopter lens with a half cyl. A previous patient with a stronger Rx was advised by the OD at Walmart not to order lenses there since they transferred all the lens manufacturing to Mexico. It seems cheap is not equal to quality.
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