Capsular tension rings are flexible plastic loops which are designed to exert outward force at the capsular bag equator to help distribute forces and help support areas of zonular loss. They are very useful in cases of trauma with focal zonular loss, and may provide additional stability in certain cases of progressive zonulopathy like pseudo-exfoliation.
In this case, the patient sustained an air-bag injury in a car accident many years ago. He did not recall this until after the surgery. At the pre-operative consultation, no zonular weakness was detected, but early during surgery it became obvious.
The CTR can be inserted at any time during the cataract surgery after the capsulorhexis has been created. It does require an intact and strong capsulorhexis as well as an intact posterior capsule. Placing the CTR at the beginning of the case can provide additional stability during nucleus removal, but it can make cortex removal more difficult because it traps it at the capsular bag equator. For this reason, the common saying is to place the CTR as soon as you need it but as late as possible.
In this case, I was able to wait until the cortex was removed prior to placing the CTR. When inserting the CTR, there should be no resistance — it should move smoothly along the capsular bag equator. If there is resistance, it may be pushing through the capsule and you should stop, refill the capsular bag with viscoelastic, and try again.
Once the CTR is placed, you can simply place your routine single-piece acrylic IOL in the capsular bag. In some cases, another option would be to place a three-piece IOL with the haptics in the sulcus and the optic captured posteriorly through the capsulorhexis.
Note that you do not have to use a CTR in all cases of focal zonular weakness. You can place the haptic towards the area of weakness to act as a bolster. And in other cases of global zonular weakness, you can take a conservative approach.
Click below to learn how to use a Capsular Tension Ring: