Abstract
Phacoemulsification is a widely used surgical method in cataract surgery with a high energy ultrasound source. The viscoelastic is considered to be tissue protective. The aim of this study is to investigate during surgery the impact of using viscoelastic versus no viscoelastic on clinical outcomes, potential complications and effect on endothelial cell density. The study group included 64 patients, who were subjected to phacoemulsification using balanced salt solution (BSS). Control group consisted of 62 patients, who underwent phacoemulsification using Hyaloronic acid 1% Healon 1%. Student’s t-test was applied for statistical analysis. The simulations of temperature changes during phacoemulsification were performed by COMSOL Multiphysics software. In the BSS group, a mean endothelial cell loss (ECL) of 4.5% was measured one month postoperatively, while in the Healon group ECL was 5.3%. Data analysis showed no significant difference in ECL between the groups (Student’s t-test, p = 0.8). No significant difference was observed in endothelial cell morphology and IOP between the two groups pre- and postoperatively (all p > 0.05). The modeling of thermo fluid dynamics showed that the heating of the cornea is slightly less when Healon was used as irrigation fluid. The phacoemulsification technique can be performed by an experienced surgeon with viscoelastics or continuous anterior chamber (AC) irrigation on the same level of safety regarding endothelial cell damage, providing equally satisfying clinical outcomes.
Highlights
The convection from the surface of the cornea has been neglected in the modeling process, because it did not play a significant role in heat transfer within the eye during the process of phacoemulsification
The outer surface of the cornea is constantly exposed to electromagnetic radiation and when the process is stopped, convection still occurs due to natural air flow and evaporation which results in tears
The aforementioned processes provide us a baseline in steady state for comparison with cases where heating effects, due to phacoemulsification, are taken into account. It enables an assessment of possible damage to the endothelial cells caused by an increase in internal temperature after heating and it possibly depends on the type of irrigation liquids
Summary
The mean endothelial cell count at birth varies significantly between 3500 and. 7500 cells/mm2 [1,2,3]. At the beginning of life, the rate of endothelial cell loss is physiologically high, and this curve flattens out during the course of life. Bourne et al calculated an annual mean endothelial cell loss rate of approximately 0.6% in adulthood [4]. The average endothelial cell count in adulthood is estimated to range between 1800–2500 cells/mm2 [5,6,7]
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