Biaxial microincision cataract surgery less traumatic

October 1, 2010

Compared with standard 2.75-mm coaxial small-incision cataract surgery, eyes treated with biaxial microincision cataract surgery sustained less trauma due to lower amounts of energy and faster visual rehabilitation.

Heidelberg, Germany-Compared with standard 2.75-mm coaxial small-incision cataract surgery, eyes treated with biaxial microincision cataract surgery (MICS) sustained less trauma due to lower amounts of energy and faster visual rehabilitation, according to the outcomes of a study.

In this prospective, randomized, bilateral study, 84 eyes of 42 patients underwent biaxial MICS and 78 eyes of 39 patients underwent the coaxial procedure. The two groups of patients were very similar preoperatively.

The biaxial procedure begins with creation of the 1.8-mm incision. According to Dr. Auffarth, Dr. Dick uses a corneal one-step tunnel that is 1.2 mm wide and 1.5 mm long at the 10 o'clock position. A second incision that is 1 mm wide is created at the 2 o'clock position. After the surgery, the microincision lens is inserted.

The standard coaxial technique requires a 2.75-mm small incision at the 12 o'clock position, a corneal tunnel that is 2.75 mm wide, and two paracenteses at the 10 and 2 o'clock positions. The microincision lens also is implanted at the end of the surgery, Dr. Auffarth said.

"The phaco power used during the biaxial procedure was significantly less compared with the coaxial procedure (26.3% versus 27.3%). Less liquid was used in the biaxial group," Dr. Auffarth said. "However, the surgical time was almost 1 minute longer in the biaxial group."

Preoperative astigmatism levels were low. Following surgery at 1 week and 1 month, there was a difference between the two groups, with the biaxial procedure inducing less astigmatism (0.63 versus 1.05 D at 1 week and 0.70 versus 0.86 D at 1 month, respectively).

The manifest refraction achieved was similar in both groups. The only difference between the groups was seen on day 1 postoperatively.

There was faster rehabilitation of the uncorrected visual acuity in the biaxial group 1 week postoperatively. By 2 months postoperatively, there was no difference between the groups.

"In the long run, best-corrected visual acuity [BCVA] did not differ between the groups," he said. "On day 1 postoperatively, BCVA was better in the biaxial group."

There was a larger initial loss of endothelial cells 1 week after the biaxial procedure, but 8 weeks after surgery that difference between the groups was no longer apparent.

"With the biaxial procedure there was significantly less trauma to the eye because of the energy used, less surgically induced astigmatism, and faster visual recovery," Dr. Auffarth concluded. "The initial endothelial cell count loss is not a relevant issue."

FYI

Gerd U. Auffarth, MD
E-mail: ga@uni-hd.de

H. Burkhard Dick, MD
E-mail: burkhard.dick@kk-bochum.de

Drs. Auffarth and Dick have no financial interest in the subject matter.