An example: a patient comes to you who is significantly hyperopic but has never worn glasses before, and therefore, has gone a long time constantly stimulating accomodation in order to see better. This patient may objectively be found to have an rx of +8.00, but because of their constant accomodation(which internally adds plus to the eye), they may not be able to accept and see well with the +8.00. The Dr. and patient would have to subjectively work together to find an rx that is both helping the patient out while they are still able to see clearly. Eventual progress with good patient compliance would allow the patient to ease their way into their actual rx so they can be properly corrected.