Near sighted or long sighted NHS lenses
Posted , 6 users are following.
hi I have been given the choice, during cataract surgery of having a short or long sited lens fitted. I am currently short sighted and was advised by my optician to ask the surgeon to leave me slightly short sighted. when I went for my pre-op accessment the optician told me, given the choice, patients normally chose to have a far sighted lens fitted. Would i struggle with having one eye that is long sited, the other (till I have cataract removal) short sighted. I have worn glasses most of my life and this does not bother me.
could I ask for opions as which lens to chose.
Ian
0 likes, 8 replies
RonAKA Cavalier
Edited
Ian, I suspect you are being offered a monofocal lens and the same lens would be used no matter which option you choose. The power of the lens and how much residual correction is left will determine whether you can see better close or at distance. Most people choose to be corrected so they can see distance without glasses. Then they need some OTC reading glasses to see close for reading. But, you also have the choice of being left short sighted and better able to see near without glasses. Then you will need prescription glasses to see in the distance, probably similar to where you are now. The choice is really a personal one, and I would suggest thinking about what you want to see without glasses on.
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There is a third choice which is to get one eye set for distance (-0.25 D target), and the other eye set for closer (-1.50 D target). If you are ok with that, then you will be able to see close and far without glasses. It is called mini-monovision, and uses the same monofocal lenses. This is the route I have gone and am 95% free of glasses. I occasionally use some mild +1.25 D readers, but that is it. I do have some prescription progressive glasses, but it is quite rare that I use them. They do give the best overall vision, but I very rarely use them. Driving at night out in the country possibly.
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As far as getting one eye done for distance and not the other, that may give you the equivalent of monovision without glasses depending on how near sighted you are. What is your latest eyeglass prescription? If the eye you are considering to not have done is around the -1.5 D mark, this may be a good solution. If it is much more myopic like -4.00 then it will not work without glasses, and you may have some issues with one eye corrected to near 0.00 and the other needing a -4.00 eyeglass correction. It depends on how myopic it will be.
Dapperdan7 RonAKA
Posted
ron , whatvis the advantage of having distant eye set at -.25 as opposed to plano?
thx
dan
RonAKA Dapperdan7
Edited
It is a small factor of safety to address the risk the final outcome may not be quite as planned. They don't want to leave you far sighted. When you target -0.25 D you gain some nearer vision because the defocus curve shifts 0.25 D to the right. There is a small cost in distance vision but 20/20 or better should still be achieved. On the other hand in comparison if you end up at +0.25, the defocus curve shifts to the left. This does not hurt distance vision much, but there is a more significant impact in close vision. It gets worse instead of better due to the shift of the defocus curve to the left.
thomas84367 RonAKA
Edited
I'm a good example of this. Both of my eyes were targeted at -.25. The first (RE) landed at -.25, the second landed at plano. I did test at 20/20 in the RE, but the LE absolutely has better distance vision (and worse near vision). The last line on the chart was 20/20, but I'm pretty sure I could have hit somewhere between 20/20 and 20/15 with my LE. There's no way I'm going to do better than 20/20 in the RE. That eye is probably somewhere between 20/20 and 20/25.
Bear in mind that both are Eyehance lens, so I would imagine that a -.25 difference is a little more pronounced than it would be with true monofocals when it comes to distance vision.
Bookwoman Cavalier
Edited
Ian, just to add to Ron's last paragraph, depending on how short sighted you are, then the discrepancy between your two eyes after surgery, especially if you get a far sighted lens, might be very disorienting.
As an example: I was very myopic, -8 in both eyes before surgery, and got -2 lenses implanted, as I wanted to remain somewhat short sighted (or nearsighted, as we say in the US). After the first surgery the 6-diopter difference between my eyes meant that while I could function ok at home (although my overall vision was very wonky) there was no way I could drive or really go out at all. Thankfully my husband was around to help, and I got the second eye done two weeks later so all was well. But this is definitely something to discuss with your surgeon.
Guest Cavalier
Edited
I agree with targetting slight myopia. As for the Anisometropia between the 1st and 2nd surgery, yes it can be somewhat disorienting. Correcting it with glasses (by popping one lens out) may be even more disorienting. Or you might get used to it. I did. Due to some complications I'm now into my 4th month post-op with just one eye done and I've gotten used to wearing glasses with a -4 sphere lens in just half the frame (other lens is plano). The best and least disorienting interim solution between surgeries though would be a soft daily contact lens in the un-operated eye. That works quite well.
Dapperdan7 Guest
Posted
hi david. whatvis the advantage of targeting for slight myopia?
thx
dan
Guest Dapperdan7
Posted
Ron posted a very good explanation of this above