Conventional Phacoemulsification Surgery Versus Femtosecond Laser Phacoemulsification Surgery: A Comparative Analysis of Cumulative Dissipated Energy and Corneal Endothelial Loss in Cataract Patients

Purpose: To analyze whether femtosecond laser-assisted surgery leads to less cumulative dissipated energy (CDE) and decreased endothelial cell loss compared to conventional surgery.

Patients and methods: This non-blinded, non-randomized, quasi-experimental clinical trial was conducted at one center and involved one surgeon. Patients with cataracts and 50-80 years old were included, and the exclusion criteria were radial keratotomy, trabeculectomy, drain tube implant, corneal transplant, posterior vitrectomy, and re-implantation of intraocular lens. In total, 298 patients were recruited between October 2020 and April 2021, and the data collected included sex, laterality, age, ocular comorbidities, systemic comorbidities and CDE. An endothelial cell count was performed before and after surgery. Patients were divided according to femtosecond laser-assisted phacoemulsification or conventional phacoemulsification. The femtolaser patients were submitted to the equipment, and then, immediately after treatment, phacoemulsification surgery was performed. In the conventional method, the "divide and conquer" technique was used. The statistical analysis was made using an analysis of covariance linear model, using SAS version 9.4 (SAS Institute, Inc., 1999). Values with p < 0.05 were considered significant.

Results: A total of 132 patients were analyzed. The only statistically relevant predictors of CDE were the severity of the cataract (p < 0.0001) and age of ≥75 years (p = 0.0003). The following factors were not significant: technique with or without laser (p = 0.6862), sex (p = 0.8897), systemic arterial hypertension (p = 0.1658), and diabetes (p = 0.9017). Grade 4 cataracts were associated with higher CDE than grade 3 cataracts, which in turn were associated with higher CDE than grade 2 cataracts. A comparison of pre- and post-operative specular microscopy with and without laser revealed no significant discrepancy (p = 0.5017).

Conclusion: Femtosecond laser-assisted cataract surgery did not reduce CDE or endothelial cell loss compared to conventional surgery regardless of severity.