When we make a corneal incision for cataract surgery, we must be careful to avoid damaging the attachment of Descemet’s membrane at that site. The trauma of bringing instruments in and out of the anterior chamber can cause an iatrogenic Descemet’s membrane detachment. Most of the time it is quite small and is easily put back into position by sealing the incision at the end of the case. However, it can become larger during the remaining procedures of the cataract surgery. In particular, if the suction port of the irrigation/aspiration tip grabs ahold of the Descemet’s flap, it can cause it to extend to the central visual axis and become quite large. In extreme cases, the patient may end up needing a future corneal endothelial transplant.
The phaco incision may not seal as well with a focal Descemet’s detachment because the endothelial pump function is no longer present at the incision site. A suture may be a good option for larger detachments in order to ensure long-term sealing of the incision. The gas bubble that is injected into the eye to help re-attach Descemet’s membrane to the cornea can be filtered room air or we can use a longer acting gas such as SF6 (sulfur hexafluoride) in a low concentration. Note that SF6 will double its volume in the first day or two and then slowly disappear after 10 to 14 days. For this reason, we use 16% SF6 which is made by mixing 0.5cc of SF6 with 2.5cc of filtered room air, creating a 1:6 ratio which is 16.7% in concentration.
This video shows how to deal with a Descemet’s detachment intra-op and after surgery:
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