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Cataract surgeons should still learn alternate surgical techniques
Knowledge of manual small-incision cataract surgery techniques will expand the armamentarium, surgical decision-making, prominent surgeon says.
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Phacoemulsification is considered the gold standard for cataract removal, but it may benefit cataract surgeons to learn other, perhaps less well-known techniques.
According to Ravi Thomas, MD, FRANZCO, manual small-incision cataract surgery (MSICS) still has a place in cataract removal, and the technique may be especially beneficial for surgeons in areas where economic disparities exist.
The technique, which uses a large tunnel — typically 5 mm to 5.5 mm — and an anterior chamber maintainer, may have clinical benefits compared with phaco, thus making it the more appropriate choice in some cases.
In addition, MSICS may be a valuable teaching tool because it introduces residents to cataract fundamentals that are also relevant to phaco. According to Prof. Thomas, how residents are trained should be considered in the ongoing discussion about what surgical techniques are learned and used in practice.
In fact, he said, the surgical technique he learned from the late Prof. Michael Blumenthal more than 17 years ago has helped him become a better teacher.
“Having learnt the Blumenthal technique, especially the large tunnel, phaco was much easier to teach. The problem for those who do phaco and then learn MSICS is usually the tunnel,” Prof. Thomas said.
Comparable efficacy, safety
Prof. Thomas said attempting phaco in all cataract removal cases is neither feasible nor practical, and it may also be undesirable. Hard and brunescent nuclei are difficult to emulsify, even with using modern phaco technology. With MSICS, the incision is large enough that any cataract can be removed without a noticeable clinical difference compared with phaco.
“From a practical clinical point of view, the Blumenthal technique of cataract surgery provides outcomes that are similar to phacoemulsification,” he said.
It is acknowledged in the published literature that phaco results in statistically less induced astigmatism, but Prof. Thomas questions the clinical impact of the difference.
“The induced astigmatism is certainly statistically significantly higher than with a 3-mm phacoemulsification, but the amount of astigmatism that produces this statistically significant difference is 0.3 D of cylinder. In most parts of the world, this would not be considered clinically significant. What difference this makes to the patients’ quality of life is debatable,” he said.
The impact of the larger incision on the health of the endothelium has been questioned, but published studies to date have not found a statistical difference in endothelial cell loss after MSICS techniques that use a maintainer compared with phaco. According to Prof. Thomas, his own experiences have led him to believe that the use of a maintainer converts the procedure into an egress system and reduces incidence of endophthalmitis and dropped nucleus.
According to Prof. Thomas, if the goal of surgical teaching is to optimize surgical outcomes among students, then the teaching aspects of MSICS are considerable. Surgical residents who learn MSICS become surgeons with a wider armamentarium of surgical options and are better informed when deciding the appropriate technique.
Prof. Thomas said surgeons should learn MSICS as an additional bail-out technique because it still results in a secure sutureless wound. An unplanned conversion to standard extracapsular surgery leads to poorer outcomes than a planned extracapsular surgery. Also, he said that MSICS has less upfront investment machinery costs and phaco is only practical when foldable IOLs are available. — by Bryan Bechtel
References:
- Thomas R. Role of small incision cataract surgery in the Indian scenario. Indian J Ophthalmol. 2009;57(1):1-2.
- Thomas R, Kuriakose T, George R. Towards achieving small-incision cataract surgery 99.8% of the time. Indian J Ophthalmol. 2000;48(2):148-151.
- Ravi Thomas, MD, FRANZCO, can be reached at Queensland Eye Institute, 41 Annerley Road, South Brisbane 4101, Queensland, Australia; +07-3010-3360; fax: +07-3010-3390; e-mail: ravi.thomas@qei.org.au.
