JUN 07, 2013
This prospective study found that femtosecond laser pretreatment results in a significant reduction in effective phacoemulsification time (EPT), reducing it to zero in many cases.
Subjects were 151 patients who underwent femtosecond laser pretreatment followed by phacoemulsification cataract extraction and IOL insertion. Results were compared with 51 controls who underwent phacoemulsification cataract extraction plus IOL insertion with no pretreatment. Demographics were similar between the groups.
All cases pretreated with the femtosecond laser underwent complete capsulotomy. Mean EPT was reduced by 83.6 percent in the femtosecond pretreatment group (P < 0.0001) compared with controls. Thirty percent of patients in the femtosecond group had an EPT of zero, compared with no patients in the control group. Just more than 57 percent of cases in the femtosecond group had a mean EPT of less than two seconds and 80 percent had a mean EPT of less than four seconds, compared with none in the control group.
The use of improved lens fragmentation algorithms reduced EPT 28.6 percent in the femtosecond group, and a further 72.8 percent reduction was attributed to use of a 20-gauge phacoemulsification tip. The overall reduction in EPT was 96.2 percent when comparing the optimized femtosecond pretreatment group with the control group. This was associated with a 36.1 percent reduction in endothelial cell loss in the femtosecond group. Visual and refractive outcomes were similar to those of conventional cataract surgery.
The authors write that lens nucleus fragmentation by laser emulsification theoretically should have resulted in higher postoperative IOP due to residual lens material causing an anterior segment inflammatory response. However, this was not the case, as no difference was found between cases and controls in terms of postoperative IOP. The inflammatory response also may contribute to cystoid macula edema. However, there were no cases of cystoid macular edema noted in this cohort.
They conclude that further research on the effect of femtosecond laser energy alone on postoperative IOP, corneal edema, endothelial cell count, and macula thickness may give an indication as to whether the reduction in phacoemulsification energy and replacement with femtosecond laser energy will lead to improved safety and better outcomes.