Folks have vastly different "systems".
Not just the shape of the eyeball (not always the same left and right) the lense capsule in the eye nor the retinas. Also the specialized nervous-system signal pre-processor they feed into.
Rare is the Doc who bothers to delve for the fine details, person A to person B of those bits.
After a near-disaster, Reston, VA facility, I escaped, took my problem to Hong Kong, found that expertise.
Dr. Dylan Chan did his part perfectly, no anaesthetics (DNA thing, plus it is HIS preference as well..) but still got a few surprises.
- Zero scar by day three under 40X magnification (DNA thing).
- Seems some folks can shift a rigid lense on the long axis with ease. "Ciliac muscles like an Olympic weight lifter!" he said. Dunno how. It just happened automagically.
Result is 20/15, sub 1/4 Diopter LR/diff, annnd ability to read the fine print on a pill bottle or see individual leaves on a tree in the far distance without need of external lenses.
It can take ten or so seconds for my eyes to MOVE that lense, "Zumar style", but it needs no glasses, any tasking, any distance.
I wasn't sure if I'd take up flying again, but had him goal for starry, starry night, major metropolitan area ground lights.
Works a treat for night driving and garish Hong Kong nights in a city of constant light-shows, too.
Downside is need of at least mild sunglasses, outdoors, most days.
UV thing, as there is no problem with high intensity light, indoors.
Night driving and fog or snow driving is outright magical. No issue with oncoming headlamps, even if on high-beam, and I can still see colours in the grass at the verge, off side.
Happy man! At 76 I see better than ever I did at 18/19, per USAF flight physical.... with one exception.
Andrews AFB had re-run one test three times with re-calibration and added observers, each go. I was clocking the widest night-time COLOUR peripheral vision they had yet measured.
No longer!
Cataract lenses do NOT do peripheral vision nearly as well as natural vision can.
BFD. I run better mirrors on the motor cars, and have re-trained - rigorously - to SWIVEL the head a LOT more.
Howard Hughes to Noah Dietrich:
"Find the experts, Noah. Find the experts."
Dr. Dylan Chan has abnormally good natural vision, works FAST with no drugs. A bit of a legend, he had done over twelve thousand lenses before age forty and leaving Government Hospital to found his own clinic.
He and his "girls" took three times as many test readings as is usual. Spread out over time of day and day of week before ever he selected the lenses.
That's how he got that sub 1/4 Diopter Left/Right match.
We also elected to NOT laser-away a window in the back of the capsule. He said the eye will try to place tissue on it.
I said no, it will not. I'll order it not to do. It hasn't.
Amazingly capable systems, humans are. No need to now HOW you command your staff. Only that you do.
The rest is built-in. Thank God in her clever engineering.
Does the USA have equally capable eye Surgeons? I'm sure we do.
But have no idea whom. Dylan was already known to our family for no-drug rebuild (several hours of it) to my Mother in Law's cornea after serious tearing and impact damage in an accident. It went perfectly.