Microincision, small-incision phaco with varied ultrasound safe for hard cataracts

J Cataract Refract Surg. 2011;37(10):1799-1805.

Microincision and conventional small-incision coaxial phacoemulsification with varied ultrasound energy settings proved safe in treating hard cataracts, a study found.

"The pulse and burst modes used less energy than the continuous mode, and this may do less damage to corneal endothelial cells in eyes with hard cataract," the study authors said.

The prospective, randomized clinical trial included 180 eyes of 135 patients. All patients had nuclear cataracts harder than nuclear opalescence 5 on the Lens Opacities Classification System III.

Eyes were randomized to undergo phacoemulsification through 1.8-, 2.2- or 2.75-mm incisions. Eyes in each group were further randomized into subgroups to have treatment with burst, pulse or continuous ultrasound energy.

Study results showed that eyes in the 2.75-mm incision group had more surgically induced astigmatism at 2 months and less incisional corneal edema at 1 week than the 1.8-mm and 2.2-mm incision groups; these differences were statistically significant (P < .05).

Ultrasound time, cumulative dissipated energy, incisional corneal thickness and central corneal thickness at 1 week and endothelial cell loss at 2 months were significantly higher in the continuous ultrasound group than in the pulse and burst energy groups (P < .05).

Mean endothelial cell loss was significantly higher in the continuous power group than in the pulse energy or burst energy groups at 2 months (P < .05).