I don't know why I never thought of this before. Today I was out back grabbing a smoke and noticed how little I notice my trifocal lines.
Bear in mind that I have plastic trifocals, Bifocals, Glass Trifocals, Progressives in both plastic and glass as well as some SV glasses for various purposes and I have a 2.50 add.
The ones I had on today were plastic ST's. What I realized was how much more I notice the line in plastic ST bifocals. Then I reasoned that the ledge was much more pronounced in the bifocals as opposed to two more shallow edges in the trifocals.
The signifcance? I often suspect that prescribers and opticians do not use trifocals because they got so much feed back when they first Rx'd bifocals for the individual (note I didn't say woman).
The point? I suspect that those with higher adds, would notice the line much less (plastic lenses) if in trifocals with a narrow seg. width. The higher the change between adjacent segements and the wider the segment, the more the patient would be consiencos of the glare and width of the segment as well as the abruptness of the jump.
Chip:idea:
Reply With Quote
Bookmarks