Option for MSICS in hard cataracts
Lens segmentation device allows smaller incisions for removing hard cataracts
Manual small-incision cataract surgery (MSICS) is widely used in resource-limited areas because it is faster, less expensive and less dependent on modern infrastructure and external supplies than phacoemulsification. Even in developed countries it can be the preferred choice for patients with very dense cataracts or compromised corneal endothelium because it eliminates the risk of ultrasound.
However, removing very hard cataracts whole with MSICS can require a scleral incision of up to 8.0mm with a trapezoidal profile that widens about 25% toward the anterior chamber. While often self-sealing, such large incisions may increase leakage and infection risk as well as postoperative astigmatism.
Using a miLOOP device to cut the lens nucleus in half in the capsular bag can reduce MSICS incision size to 4.0mm-to-5.0mm, David A Crandall MD told the ASCRS ASOA 2019 Annual Meeting in San Diego, USA. The device, which consists of a retractable nitinol loop that ensnares the lens nucleus, is also useful for segmenting cataracts to reduce ultrasound in phaco procedures, he added.
“With dense lenses one of the most difficult parts is the posterior plaque, and you are guaranteed to make it all the way through the lens.”
Reusing the device
The Minicap MSICS procedure Dr Crandall described involves inserting the miLOOP device into the capsular bag beneath the capsulotomy edge, using the thumb slider to expand the loop in the iris plane, then pushing it peripherally and rotating the loop to surround the nucleus in the sagittal plane. Retracting the loop with the thumb slider pulls the filament through the cataract, cutting it in two. The segments are then prolapsed into the anterior chamber and extracted using a lens loop or simcoe I/A cannula. A foldable lens can then be inserted without enlarging the incision.
Dr Crandall, of the Henry Ford Health System in Detroit, USA, noted that the miLOOP device is labelled for single use in developed countries, but can be sterilised with spirits and reused at least 50 times.
“They are very durable,” he said.
Dr Crandall advised mastering the miLOOP in softer cataracts where the loop passing behind the nucleus can be seen as well as felt before attempting dense cataracts, where it must be done by feel alone. He also advised using a second instrument to prevent the nucleus from prolapsing during segmentation, and to complete segmentation as the loop may not completely separate the fragments. Viscoelastic is used to open the capsular bag for loop insertion and to protect the cornea during segmentation.
David A Crandall: DCranda1@hfhs.org