Posted , 7 users are following.
I'm beginning to discover that it's possible one needs more light to read using an IOL (set for near) than pre-cataract surgery.
Would someone like to comment on anything they have learned thru trial and error regarding lighting when reading after cataract surgery?
0 likes, 10 replies
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RonAKA Julissa
Posted
There is almost no light that is too bright to see in. That is why the light levels in operating rooms are so high. The brighter the light the more the pupil in your eye closes down. The more closed down it is the deeper the depth of focus. It is kind of like the aperture in a camera. In an old 35 mm SLR a f1.4 aperture gives a very shallow depth of focus. A f16 gives a very deep depth of focus.
soks RonAKA
Posted
i am on pupil constricting drops for positive dysphotopsia and they do not make the visual acuity any better.
in fact it makes it worse to see at night as the pupil is small and not much light is not passing through the small pupil.
RonAKA soks
Posted
Yes, there is no free lunch. A constricted pupil lets in less light. That is why in a camera if you use f16 for aperture then you need a really slow shutter speed. The eye has no real way to slow down the shutter speed.
soks Julissa
Posted
that has been my experience as well. better lighting results in better vision but its not like it makes it 20/20.
ara21947 Julissa
Posted
its definitely true since the eye cant naturally adjust the way it used to. If the print is small I now need to move closer to a light source. I notice in restaurants when I could read the menu by candlelight now I need a real light.
Guest Julissa
Edited
Yes, it is well known, even monofocals have loss, they let about 95% light come through.
And premium lenses are worse in this regard than monofocals, Edof are closest to monofocals, Symfony is about 92%, trifocals are somewhere around 85-88% and some of the older bifocal designs are worse.
So lighting plays a bigger role after iol implant, no matter what lens you have chosen.
That said, cataracts also makes it difficult for the light to come through, so depending on how much cataracts you had, some still find the iol better, that was the case for me.
RonAKA Guest
Posted
I am not so sure that light transmission through the IOL is the problem. If anything a clear non blue light filtering IOL lets more light through than the natural crystalline lens. The blue light filtering lenses more closely simulate the natural lens, but over all may still exceed the natural lens. That is why some think the clear lenses may be damaging to the retina over time. There seems to be no clinical data to back that up though.
Chris53317 Guest
Posted
No problem here reading in low light with my PanOptix trifocal IOL. I have an adjustable LED lamp (not a reading light) beside me turned to a fairly dim setting and I am able to read the newspaper. Obviously more light would be better, and I would not try to read the full paper at this level. I have not tried reading in candlelight..
Guest RonAKA
Edited
It is a well known fact that good lighting helps a lot after iol implants, even the eye doctors advice us to remember good lighting after implants, or those eye doctors I have seen does.
When the iol steals some of the contrast, we can compensate either with extra light or glasses.
If you are in a situation, where lighting is not optimal, better lighting and glasses have the same effect, both will make you able to see better close up, it is very obvious for us with iols.
I can see the menu at a restaurant in dim lighting, but it is well know that not all with iols can do this. Many of us with iols learn to use the light in our smartphone, when we are out somewhere and struggling to see something close up.
The Panoptix is at 88% overall, and it only allocates 25% of that to near vision, and 25% to intermediate, the contrast loss is one of the main reasons why multifocals are not recommended if you have other eye issues, and also one of the main reasons why some surgeons refuse to use multifocals at all.
RonAKA Guest
Posted
Yes, there are probably at least two effects coming into play. One is that if the IOL is not ideally focused at the distance you are trying to read at, then more light will allow the pupil to constrict and increase the depth of field to compensate for the IOL being somewhat off focus. The second effect that I believe you are describing is how sensitive is the eye to light. If more area is dedicated to seeing something then you can probably see better in low light. This is like the megapixel wars in cameras. There was a race to give users more and more megapixels of resolution, especially in cell phones, where space is limited. Megapixels were easy to compare and buyers thought more was better. Yes they could give lots of resolution but they did it by reducing the size of each pixel, because they had no room to increase the overall sensor size. The small pixels lost their ability to reproduce accurate colour as the light level went down. A quality camera has a large overall sensor size and a moderate number of pixels of resolution so each individual pixel is much larger and more light sensitive. So, yes, dedicating less of the eye to a certain distance is certainly going to make it harder to see in low light.