Very interesting ophthalmologist views

Thanks Lynda111. There's also an article entitled What Is Better-Tolerated After Cataract Surgery: Residual Hyperopia or Residual Myopia? that points to the primary research. It looks like this was an ancillary finding of the study, not the stated main purpose. But the study used outcomes from over 17,000 patients, so the conclusion may be highly credible. I have not studied the paper, so can't say for sure. Regardless, it's intriguing.

Imagine if you had a pair of blue light filtering glasses with one yellow lens removed-- who would want to wear those all day?

Based on a retrospective study of patients where one clear and one blue light filtering IOL was implanted inadvertently, 80% did not even notice the difference until after they were told about it. None found it bothersome.

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" Four of five patients had no spontaneous color vision complaints. When these patients were informed of the unintended mismatch, all remarked that they could perceive a color vision difference, but that it was not bothersome. One of the five patients reported "beige" vision. None of the patients wanted an IOL exchange."

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https://pubmed.ncbi.nlm.nih.gov/16678519/

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The blue light filtering in IOLs is very slight. It is only done to restore the colour balance of the natural lens. It is more important for those doing photographic digital dark room work and want to get the colour balance right especially for paying customers that have natural vision eyes.

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I went 18 months with one eye done (with a blue light filtering lens) and the other eye with a minor cataract. To me there was a very obvious difference in the colour balance. The cataract eye was much more warmish yellow. I had not noticed it until after the surgery and I had something to compare to. When looking at people's faces on TV I decided that the warmer cataract coloured eye was more flattering to their appearance. But I would only notice this difference when closing one eye, and then closing the other eye. With both eyes open what I saw was a blend of the colour balance.

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I suspect the difference between a cataract eye "warm" is much more dramatic than the difference between an IOL clear lens and a blue light filtering lens. I would have no hesitation if the circumstances warranted to have a blue light filtering lens in one eye and clear in the other. That said, I have blue light filtering in both eyes as I want a natural colour balance. Back when we used florescent lighting I always preferred the warm daylight tubes to the cold bluish light tubes.

Ron… have you considered that it may have been the cataract itself in you natural lens that was causing it to have such a pronounced "warm" colour compared to your IOL eye between surgeries? I remember coming home once after an appointment before I'd had any surgery done and my pupils were extremely dilated and everything wasn't just warm but very unnaturally brownish. Not warm… brown. That didn't seem natural and I assume it was from my cataracts.

Yes, for sure the warm colour was coming from the cataract in my natural lens. The colour it induces in the vision is very striking compared to the slight yellow tint in a blue light filtering lens.

The surgeon is only identified by the initials M.G.? The differential iol range of -.75 to -1.75 D of myopia would not be appropriate for me and many others. It goes from the upper limit of mini to full monovision. Several unique variables here, like small sample size, twice the number of females, and no control group. Even included a lens exchange.

There is no standard for what mini-monovision is called. My opinion based on many different studies and articles is that mini-monovision goes from -1.25 to -1.75, with -1.50 the nominal ideal differential between the eyes. There is good evidence to support that. And don't forget that if your distance eye, done first, comes out at the ideal -0.25 D then the ideal for the near eye goes up to -1.75 D. A range of -1.50 to -1.75 is a realistic target considering the inaccuracy inherent in the power calculation.

Based on the reports of 'refractive surprise' outcomes, I have concluded that it is prudent to use the same the same brand of iol in each eye, target distance with no or small difference in lens power, and avoid MF and EDOF lenses based on manufacturer warnings on suitability/contraindications. I am personally concerned with the safety of LAL with UVL directed to eyes in adjustments.

PCO prevention needs a solution. It appears to occur from the surgery trauma itself and not just the friction of the iols. How to clear out the epithelial cells before lens placement without damaging the capsular bag?

Yes, I think it is a good idea to use not only the same brand, but the same lens model in each eye to get the most consistent accuracy from the IOL power calculation. But, sometimes larger differences in the eyes can drive the choice to different lenses due to power availability by brand and model type.

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Lens power required is going to be driven by the eye measurements and you cannot choose to use the same power in each eye unless you are willing to live with a different outcome refraction in the eyes. Normally the eye measurement and target for outcome drives the power choice. It would be unusual to use the same power in each eye.

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According to RxSight the LAL has a UV resistant coating on the back side of the lens, and none on the front side. This allows the use of the UV adjustment to change the power of the lens without damaging the eye behind the lens. For this reason the lens must be installed properly and not back to front, as it would not be possible to adjust the lens with the UV blocking coating on the front side.

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I don't think the causes of PCO are fully understood. Alcon have produced some studies that show their specific material is more resistant to PCO (lower YAG rate). Sharper lens edges also seems to help prevent PCO. And surgeon proficiency is cleaning the capsule without damaging it is a factor too. I have even seen a study which found that diabetics taking metformin for treatment have lower PCO rates than those not taking metformin. But, that does not seem to have worked for me. I have been taking metformin for many years and I now seem to have indications of PCO in both eyes. Both are Alcon material, one has sharper edges (Clareon) than the other (AcrySof IQ). So despite having all the right things in place it still can happen. I think the other issue with PCO is that YAG can be used as a bit of a "cure-all" for patient complaints, and I suspect it is done in many cases when it was not really necessary. I was relieved when I got a second opinion on my PCO diagnosis and the laser specialist recommended against doing it until it starts to impact my vision.

One of the really interesting findings in the Juvene studies is essentially no PCO in any study participants years after surgery. It may be the bag-filling nature of the implant that prevents PCO. Filling the bag completely keeps it closer to it's natural state. I suspect the shrink wrapping effect with current IOLs which results in the two inner faces of the bag touching each other may be what causes PCO.

A plausible explanation. Beware of the wrinkles there and elsewhere.

Filling the bag also means no wrinkles. And no shifting of the lens position either (effective lens position). There will be a lot of benefits when these next generation bag-filling (and often accommodating) designs finally become available.

I am not so sure about the bag filling theory being the key to preventing PCO. The Alcon AcrySof material has been found to be more resistant to PCO than other materials. The refractive index of AcrySof material is the highest of all commonly used material for IOLs. This makes for the thinnest lenses for a given power and the least bag filling potential.

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https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220498

some people refer to capsule wrapping as pco. it not real opacification but causes light effect. i think i see some effects. example maddox rod caused by capsule fold is addressed by YAG. he us referring to juvene which will prevent capsule fold and hold the epithelial cells at the bag perimeter.

filling it with what?

The IOL

The Juvene trail at 3 years has shown no capsular wrinkles, folds, or PCO. It's a small cohort but still seems encouraging. Who know if / when it will ever be available but I just think it is interesting how it doesn't seem to cause PCO. Other bag filling implants that are being studied have shown the same thing I think.

PCO can be inhibited but not yet truly prevented after cataract surgery. Optic edge design and IOL material have both been found to be associated with the speed at which PCO develops, as have patient demographics-- age, gender and degree of myopia. There are studies indicating that devices which hold the bag in a more open position after removal of the crystalline lens can also inhibit PCO, possibly by allowing for the circulation of aqueous humor. I was offered a CTR with the promise that it would prevent PCO after surgery, since studies have shown it can delay the onset of PCO and need for YAG in extreme myopia.

However since nothing has been proven to completely prevent PCO, and as I have all the demographics associated with fast PCO development (relatively young, female, extreme myope), I have accepted that YAG is definitely in my future and think I shouldn't get overly fixated on trying to prevent it.

Yes, it is not possible to ensure 100% avoidance of PCO in everyone, but I also think the true rate of YAG is not as high as is reported in may places. YAG can be done for other reasons, including being done when it is not really justified. See the study at the link below. From the conclusions "the true rate of Nd:YAG carried out for PCO at 1 year was 3.5% and at 2 years was 8.5%."

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569058/

my ship has already sailed so i am not really looking at the newer technology. it seems the pco starts at the periphery of the capsule so any blocker in that region should help with pco mitigation.