Advantages of the Staar nanoFLEX® IOL over the Crystalens® IOL
Note that all of the above limitations also apply to the Crystalens® IOL which has a price tag of approximately $1,000 more than the Staar nanoFLEX® IOL.
Why would anyone choose to pay a thousand dollars more for an intraocular lens that does not consistently provide better vision after cataract surgery than can be expected from the Staar nanoFLEX® IOL?
In theory the Crystalens® should provide a greater range of vision without the need for glasses compared to the Staar nanoFLEX®. However, I have not been impressed with the results of the Crystalens IOL. Indeed, I’ve found the Staar nanoFLEX® IOL provides almost as much range of vision as the Crystalens® IOL with a more predictable refractive outcome.
Annoying Aspects About Crystalens® IOL
The Crystalens® IOL has some other annoying aspects about it – bothersome enough that I have completely abandoned this IOL and will no longer even offer it to my patients in need of cataract surgery:
The central (usually round) part of the intraocular lens is called the “optic”. This is the working part of the lens that focuses light onto the retina. The optic of the Crystalens IOL is particularly small – only five millimeters. This allows it to be injected through a small incision, but there are downsides. A major downside is commonly noted in people whose eyes dilate really well at night or in low light. If the pupil (the dark circle in the center of the eye) enlarges beyond 5mm the light can bypass the lens causing glare at night after cataract surgery. This can be particularly bothersome to those who need to drive at night.
For a number of reasons, nighttime glare is seldom experienced with the Staar nanoFLEX® IOL. The fact that the optic area of the Staar nanoFLEX® IOL is over 40% larger than the Crystalens® optic likely plays a part.
Minimal Ultraviolet Protection
The Crystalens® intraocular lens (IOL) blocks less ultraviolet light than do most other IOLs available in the USA. Ultraviolet light may play a role in development of macular degeneration. As such, I want my patients to have more, not less, protection from ultraviolet light. With most other IOLs I still instruct my patients to wear sunglasses when outside after cataract surgery. In those who choose to have the Crystalens® IOL, however, wearing sunglasses with an ultraviolet filter is mandatory for life after they have had cataract surgery.
“Z-”, “U-” and other “Syndromes”
Intraocular lenses (IOLs) are kept centered in the eye by little wings, arms, or plates called “haptics”. The Crystalens® haptics are very flexible. This flexibility is thought to be one reason why this lens can provide such a wide range of vision without spectacles after cataract surgery. However, this flexibility can also lead to some risks not seen with other less flexible IOLs.
As the eye heals around the lens the IOL is essentially locked into place. That’s generally a good thing as it keeps the IOL from jiggling. Although most modern IOLs are somewhat flexible, they are nevertheless rigid enough to maintain their shape in the eye. The Crystalens®, however, is so flexible that it has a tendency to become twisted into shapes called “Z-syndrome” and “U-syndrome”. With either of these syndromes the vision will be limited with essentially no added range of vision after cataract surgery.
These undesirable syndromes are often treated with a procedure called YAG laser capsulotomy. Unfortunately, this laser treatment doesn’t always work. Patients are then left with poor vision or the need to remove and replace the IOL. Such a procedure is called “IOL exchange.” However, the Crystalens® is…
Difficult to “Exchange”
Given all of the above issues, it’s not uncommon for someone with a Crystalens® IOL to wish for it to be removed and replaced with another IOL (an “IOL exchange”). Unfortunately, the Crystalens® IOL is particularly difficult to remove as its design includes whisker-like projections that act like anchors inside the eye. Additionally, many patients who initially complain of blurred vision or glare are advised to have a procedure called YAG laser capsulotomy which opens (or “breaks”) the bag holding the lens. As with a fine crystal store, “You break it, you buy it” is generally the rule with this IOL. Few surgeons are skilled enough (or willing, if skilled) to remove and replace a Crystalens® IOL after YAG capsulotomy.