MSICS and phaco
Mastering both techniques has advantages in developed and developing areas.
A phacolytic patient who is due to undergo MSICS has a hard nucleues. Image courtesy of R Vivekanadan MD
Manual small-incision cataract surgery (MSICS) and phacoemulsification each offer advantages that make mastering both worthwhile regardless of practice location, V.R Vivekanadan MD told the ASCRS ASOA 2019 Annual Meeting in San Diego, USA.
For regions with great cataract need and few ophthalmologists to meet it, including India, much of Asia and most of Africa, productivity without sacrificing quality is paramount, said Dr Vivekanadan, of Aravind Eye Care Systems, Madurai, India. For these areas, MSICS offers distinct advantages.
On the quality side, MSICS visual outcomes are excellent, with best-corrected visual acuity similar to phaco across a range of cataract densities with similar complication rates – though phaco holds the edge in uncorrected VA due to less astigmatism, Dr Vivekanadan said. However, MSICS is significantly faster, less expensive and requires far less equipment and consumables.
Several large studies have found MSICS procedures averaging about eight-to-nine minutes with many under six minutes, compared with 12-to-15 minutes for phaco, Dr Vivekanadan noted. “In a busy facility, a surgeon would be capable of handling higher volume with manual, sutureless, small-incision cataract surgery.”
The surgical time also does not vary very much with the MSICS technique. For an experienced surgeon it takes more or less the same time for all types of cataracts, and can be much faster with harder cataracts because of minimal or absent cortical matter.
MSICS is significantly less expensive as well. One study in India found the total allocated cost of MSICS averaged $15 per case, just over one-third the $42 for phaco. Factoring out fixed facility costs of $10 per case, phaco is more than six times more expensive. Costs are higher for phaco equipment as well as consumables, such as tubing and tips, and foldable lenses, putting it out of reach financially for many in developing countries, Vivekanadan pointed out.
While MSICS requires no sutures and less follow-up than earlier manual procedures, phaco incisions are even smaller and recovery easier, Dr Vivekanadan said. Where MSICS generally is done under a sub-Tenon’s block often administered preoperatively by a resident or fellow, topical anaesthesia is sufficient for most phaco procedures. Patients are less likely to experience hyphema as well as conjunctival congestion and tenderness after surgery, and corneal complications may be reduced with phaco. Perhaps most significant, induced astigmatism is less with phaco, and a wider variety of foldable lenses are available than the PMMA lenses used in MSICS, leading to better uncorrected visual outcomes.
These advantages make it easy to understand why wealthier patients prefer phaco – and why it’s desirable for surgeons in the developing world to master it. The revenue that paying patients bring in not only supports ophthalmologists and their training, in many cases, including Aravind, it subsidises procedures for those who cannot afford to pay anything.
But why would surgeons in developed countries want to master MSICS? In two words, challenging cases.
MSICS often is better suited for brunescent, glaucomatous and traumatic or subluxated cataracts, Dr Vivekanadan said. In addition, complications such as zonular dialysis or posterior capsule tears may require conversion to MSICS. Conversion may also be indicated if there is a risk of losing the nucleus into the vitreous or a risk of damaging endothelial cells from excess ultrasound, irrigation and anterior chamber manipulation.
“Continuing phacoemulsification can lead to further complications.”
Learning MSICS and phaco
Generally, MSICS has a shorter learning curve than phaco, though visual outcomes are more dependent on surgeons’ skills, so learning proper technique is essential, Dr Vivekanadan said. Steps to learn include constructing scleral tunnels to minimise astigmatism and ensure self-sealing, creating a larger capsulorhexis and complete hydrodissection and hydroexpression of the lens.
Phaco requires learning phacodynamics, including application of power, vacuum and aspiration rate to maintain chamber stability. The learning curve is steeper, and risk of complications such as posterior capsule rupture is higher during training, Dr Vivekanadan noted.
Overall, MSICS is faster, with correct vision similar to phaco, and safer for denser cataracts and complicated cases, while phaco is generally less painful and gives better uncorrected vision, Dr Vivekanadan said. Both have a place in the cataract surgeon’s armamentarium.
VR Vivekanadan: firstname.lastname@example.org