Coaxial microphacoemulsification performed through a 2.2 mm incision is a new technique available to cataract surgeons skilled in phacoemulsification. The technique affords patients the combined benefits of ultra-small incision surgery and conventional foldable IOLs, announced Robert H. Osher, MD, professor of ophthalmology, University of Cincinnati College of Medicine, and medical director emeritus, Cincinnati Eye Institute, Cincinnati, Ohio, USA.
The coaxial microphacoemulsification procedure has been made possible by the availability of a new ultrasound sleeve (Ultra Sleeve, Alcon Laboratories) that is used with the Infiniti phaco system and the Infiniti flare tip (Alcon Laboratories). The new small-diameter sleeve permits surgery using high flow rates and vacuum levels to enable chamber maintenance and protect against thermal and mechanical injury while allowing efficient emulsification of the nuclear material.
With a new technique for IOL implantation and using a plunger-type injector (available from ASICO or Duckworth and Kent), Osher has been able to implant a currently available 6 mm, single-piece acrylic IOL (AcrySof SN60WF or ReSTOR, Alcon Laboratories) through the 2.2 mm incision without enlarging it.
"I believe coaxial microphacoemulsification represents the next major step in the evolution of cataract surgery," Osher said. "Surgeons accustomed to performing coaxial phacoemulsification can easily transition to this procedure using the same fluidics to maintain a safe intraocular environment and can implant a conventional foldable IOL through a smaller incision than ever before.
"My patients and I have been enormously satisfied with the outcomes of this procedure, and I anticipate that its attractive features and freedom from a difficult learning curve will lead to its rapid, widespread adoption among cataract surgeons worldwide," Osher added.
Coaxial 2.2 mm microphacoemulsification reduces surgically induced astigmatism
Coaxial microphacoemulsification performed through a 2.2 mm incision results in significantly less induced astigmatism than conventional coaxial phacoemulsification through a 3 mm incision, said Samuel Masket, MD, clinical professor of ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, USA.
To study whether the new small incision coaxial technique has an advantage for being more astigmatically neutral, Masket performed a comparative clinical study. Patients included had no surgical complications or corneal pathology, and all surgeries were performed through a temporally oriented clear corneal tunnel incision. The coaxial microphacoemulsification technique was performed using a 1.1 mm tip and the new ultra-infusion sleeve using the Infiniti system (Alcon Laboratories). No eyes had limbal relaxing incisions and astigmatism was measured preoperatively and after six weeks with autokeratometry by a masked technician.
Data from a series of 32 eyes showed surgically induced astigmatism was 0.11 D for the 2.2 mm incision group compared with 0.33 D for the 3 mm incision group (p = 0.001). The axis shift was also significantly less with the smaller incision compared with the 3 mm incision, 13.4 versus 21.1° (p = 0.03). Results were similar in a second group of 16 patients who had surgery through a 2.2 mm incision in one eye and a 3 mm incision contralaterally.
"These data show a statistically significant and possibly clinically significant advantage for the smaller incision. Further studies should be directed towards investigating whether the smaller incision also has benefits for better wound stability, leakage and risk of postoperative infection," Masket said. He has no financial interest in Alcon Laboratories.