Hi, my husband has vision problems, and has been prescribed prism lens. We now will visit the optometry shop to get the prescription filled, but we are very interested in finding out about others' experiences with prism lens. What can you tell us about this topic? Will there be a long adjustment period? Is it difficult to become accustomed to these lens? Will they affect his walking, going up and down steps, etc? Cost compared to bifocal lens? Any info would be very helpful!