Can Someone Briefly Explain the Concept of Diopter Numbers?

Thanks again Ron! Very interesting stuff and you explained it quite well. As you might remember, I'm plano in my left eye with a mono-focal and, like you, I can see maybe 20-22 inches out to "infinity". So in my quest to become fairly spectacle independent I'm probably shooting for that -1.00 to -1.50 range I think for the other eye.A couple of more questions if you happen to know:

1. Do you think it's easier to hit a reasonable sweet spot with a lens like the Eyhance or Vivity rather than a standard monofocal in my remaining eye?
2. How much worse do you think the distance vision would be with, say, a -1.0 or -1.50 offset compared to my good 20/20 eye? I mean, it can't possibly be worse than what it is with my cataract affected eye, right? I would imagine there's still some visual information "gain" or help from the non-plano eye in this scenario, no?

Thanks again.

IG

Just a suggestion - don't have this setup myself but back when I was first on the forums there was a 201a who suggested having a monofocal for best corrected distance and a Symfony (EFOF) lens targeted for -1.0 in the other. Thought being the brain would take the better view. The monofocal would then cancel out Symfony's night time concentric rings around certain lights but provide that great intermediate/reading distance you want. EDOF lenses do not split the light as much as a trifocal like PanOptic and vision is seamless. Trying to recall individual that did go with that setup and was very pleased with the result.

Might be something to discuss with your surgeon as an option.

Although never a guarantee - but if achieved it is great to not have to wear glasses. I wore them since childhood - few years did wear contacts that gave me that for awhile but eyes got too irritated with them after a few years so had to go back to glasses.

Hi Sue.An! (apols for this long post)

Yes, that's an interesting thought and one that has indeed hit my radar. Thanks for reminding me. I do recall having read that the typical issues (rings, flares, etc) involved around some of the multi-focal or EDOF lenses can indeed be mitigated with the use of one mono-focal lens in the opposite eye. It definitely sounds like a potential option in my case.Now, what intrigues me (rightly or wrongly) about the Eyhance lens option that I mentioned earlier in this thread is what they claim is something like 30% greater light concentration ability over some other lens options, etc. implying that the image is basically "brighter" in the eye (I guess) AND without sacrificing much distance vision as well. Ack, It's all so overwhelming sometimes keeping all these in my head and balancing the pros and cons!

I do feel I'm fairly low hanging fruit for a satisfactory outcome if the surgeon can target -1.0 to -1.50 and achieve it such than I can read around 15-20 inches out in that one eye.Speaking of mono-vision I recently dug out some email correspondence with my surgeon from a few years ago and I had brought up the subject of eye dominance. He said that given my bilateral cataracts he really couldn't quite figure out which of my eyes was the dominant eye.On some tests my right eye is dominant (even though I'm left handed generally speaking), whilst in others I'm left eye dominant. He said he targeted my left eye for distance (successfully) and figured that if I tolerated my existing mono-vision well we could, at some future point, target my other eye nearer.THEN, I read recently that if an individual gets an IOL in one eye only it can actually CHANGE someone's eye dominance in something like 20% of cases. Kind of strange, but interesting at the same time. In any case, I'm not going to get too hung up on eye dominance because, and as I think you've mentioned too, at the end of the day it probably doesn't matter much provided the difference in eyes isn't too, too great. I'll be putting the Symfony lens on my list of items to discuss with the clinic. I've got an appointment now for 17th March. Thanks again.

1. The advantage in my view of a EDOF lens instead of a monofocal is that your distance vision is likely going to be better. I would suggest that a target of -1.5 D is close to ideal for a monofocal, while an Eyhance target would be -1.25, and a Vivity target would be -1.0 D. You gain some distance vision because you use less myopia to gain reading. The other effect is that the defocus curve of an EDOF is slightly flatter so yes it may have a wider "sweet spot". I was willing to go ahead with the Vivity, but my surgeon discouraged me. He seemed to classify me as a hard to please perfectionist (which may be correct!). When I asked him what his experience was with the Vivity, he said he had another patient that had high expectations and was not happy with it.
2. I simulate -1.25 D monovision with a contact. I am looking at the TV which is about 15 feet away. I can of course read all the text perfectly with my 0.0 D IOL eye. But smaller text (news channel banner) is readable but just barely with my -1.25 eye. I also have a cataract going on, so I am hoping that when I get to a real IOL -1.25 without the cataract, it will be better. With both eyes open now I see a nice crisp image at 15 feet. The brain seems to be able to still use both images and make an overall good sharp one. Closing my -1.25 eye does not improve the overall picture.

Yes based on what my surgeon said - don't get too hung up on which eye is dominant. I thought based on tests I was left eye dominant but it was because cataract was worse in RE. Left eye must have learned to be dominant. Now with cataracts removed I know I am Right eye dominant.

Yes, I think that optically the Symfony could be used for the closer vision eye in monovision. I would think -0.5 to -0.75 D of myopia would be enough to get decent reading vision, and distance vision with that eye should be pretty good. I am less sure that the brain would ignore the night effects of halos and flare though.

Yes -.50 or -.75 shoukd be enough to target for 2nd eye to get that reading distance. I believe with healing process i have -.25 anyways but now with inly one eye seeing well due to epiretinal membrane it still surprises me how well i see all distances with symfony

no there is no mitigating the night time concentric rings I see around certain light sources with 2 symfony IOLs. I think only a mono focal paired with symfony could do that.

Hi Valerie - I have 2 Symfony lenses but for whatever reason (some say depends on shape of one's eyes or pupils) you can see more. I read comfortable from 11 inches to full distance. Rarely do I wear glasses. Do see the concentric circles at night with these IOLs. Would it help if surgeon targeted another EDOF lens for -1 to be able to get better near vision?

Hi Sue.An2 - It's amazing that you can read comfortably at 11 inches! That's 28 cm (I'm in Brazil and I'm more used to the metric system)! You suggested if the surgeon could aim for -1D for the other eye, that would be mini-monivision, right? Do you have this arrangement with your Symfonys, or can you read the same distance in both eyes individually? When you say that you "rarely wear glasses", is it because at some point you still depend on them? When? Sorry for so many questions.

Hi Valerie - I do not have monovision with my Symfony lenses. Both were targeted for plano. Perhaps LE was .25 closer just due to healing process. Currently have another condition called epiretinal membrane so do not see the best put of left eye. Both eyes open though can still see well - no need for glasses.

it is so rare I need glasses - usually in low light conditions or to read a pill bottle. Only other time is when I am reading for prolonged period of time (novels).

As an example I had to repair my sunglasses - little screw came out - was able to fix it no glasses required. I feel fortunate that my near vision is do good as well as distance and everything in between.I was expecting computer distance to be great and I need that for work but to be able to hold iphone at usually distance - elbow bent I am very happy.

i mentioned targeting your other eye at -1.0 and due to symfony being an EDOF lens there should be seamless vision.

One other thing I should add is although after first surgery I could read well enough it definitely greatly improved after 2nd operation.

I'm grateful for the feedback! Unfortunately, the best close focus I can get with my Synfony (alone) is around 20", but I can even see at 16", but it's not very comfortable to use my phone. My right eye, due to cataract, became myopic and with that I can see at 8" and I've gotten used to it, so I've postponed the surgery of that eye three times...

If you can delay your surgeries always best - never know when a better lens is available.