Quiz: What is the problem here? Look Carefully!

This case seemed like a routine cataract surgery. Everything went smoothly. A good incision, a nice round capsulorhexis, easy removal of the nucleus and cortex. But now, upon insertion of the IOL, something is wrong. There is a problem and you can see it in the photo above. Stop reading here and study the photo in detail to see if you can figure it out. The answer is below.

If you didn’t figure it out, I’ll give you a hint:

In this case, the IOL is upside down in the eye. Remember that the IOL should never have the S orientation. S is for Stupid mistake, Silly error, or Sadness situation — remember it however you wish, but imprint this into your mind forever.

Another way to look at it is the 7L rule: as the haptics unfold, make sure that the first (leading) haptic looks like a 7 and that the second (trailing) haptic looks like the letter L.

What is the effect of the upside down IOL? It depends a lot on lens geometry. If the IOL is vaulted, then reversing the vault with greatly alter the effective lens position. For an IOL which is normally posteriorly vaulted, placing the IOL upside down will cause the optic to be displaced anteriorly in the eye, resulting in a myopic refractive outcome. You could also get a pupillary block from this situation.

Also the optic design makes a difference. The the refractive power of the eye changes when it is upside down depending on the optic configuration. For a biconvex IOL where the power is split between front and back surfaces there is not much refractive change via the optic, though the haptic angulation will change the ELP. For the biconvex IOLs where the power is asymmetrically applied there can be about a -1 diopter change. Finally, for a plano-convex IOL there can be a +2 diopter surprise. Bottom line: Don’t insert the IOL upside down!

In this case, the IOL is a biconvex design with equal split and it is a single-piece planar design without haptic angulation. The patient had a similar refractive outcome to placing the IOL in the eye correctly. My preference would still be to re-orient the IOL into the correct position during this case. Using the IOL roll technique, it could be flipped without damaging the corneal endothelium or the capsular bag.

This case was an anonymous submission and we are thankful to our readers for being generous with their complicated cases. It is so helpful for all of us to learn from each other. Please consider submitting your video via this link.

Click below to learn from this interesting quiz case:


  1. I initially thought it was a kinked haptic on a three piece IOL then I realized what I thought was the haptic option junction was actually the tip of an optic implanted upside down…

    That was fun!

    I love these posts.

    1. thank you doctor — please submit a video of your own to this site (anonymous is ok too!)

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