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Microincision allows safe injection of foldable IOL
J Cataract Refract Surg. 2008;34:1748-1753.
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A single-piece 6-mm foldable hydrophobic acrylic IOL may be implanted through a 2-mm tunnel incision with new injector systems and suitable docking techniques.
IOL implantation required minimal enlargement of the incision, about 3% to 4%.
In a prospective, randomized trial that included 100 patients with a mean age of 70.53 years, phacoemulsification was performed through 1.8-mm to 2.2-mm keratome incisions. After bimanual aspiration and viscoelastic removal, patients were implanted with the AcrySof SN60WF IOL (Alcon) with the Monarch II injector (Alcon) and C cartridge or the Monarch III injector and D cartridge.
Two surgical techniques, direct implantation and wound-assisted implantation, were used on the eyes, which were assigned to one of four groups according to injector type and surgical technique used.
The smallest incision sizes, at a mean of 2.09 mm, were with the Monarch III injector and D cartridge and wound-assisted implantation. The largest incisions, at a mean of 2.86 mm, were with the Monarch II and C cartridge and direct implantation.
“Use of the direct implantation technique caused statistically significantly greater incision enlargement than the wound-assisted technique,” the study authors said.
The take-home message is that incision sizes for cataract surgery are getting smaller and smaller, with complete cases, including IOL implantation of a popular acrylic IOL, being done via incisions of 2 mm. This is another for surgeons to consider using a smaller incision for routine cataract surgery.
Microscopic tears at the incision may make it less likely to seal well and may induce more astigmatic flattening. It is likely better to easily implant an IOL through a sharply cut 2.2-mm incision rather than squeeze it through a 2-mm incision and inadvertently tear or rip the incision, even if microscopic. Also, with the wound-assist technique in which the injector tip is abutted against the incision, is there a risk of tear film contamination of the IOL? What is the IOP during IOL insertion with the wound-assist technique?
Smaller incisions typically induce less astigmatic effect and tend to self-seal better than large incisions, but is there a sufficient difference between a 2.5-mm incision (direct implantation, with injector tip inside the incision) vs. a 2.1-mm incision (wound-assist technique) to warrant the change in technique, the risk of tear film contamination of the IOL, the induced high IOP during implantation and the potential for incision stretching/tearing?
– Uday Devgan, MD, FACS
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Section Editor