# An Alternative Approach to Cataract Surgery Using BSS Temperature of 2.7 \({}^{\circ}\)C
## 3 Results and Discussion  
P preclinical phase data showed that over a time of about 20 min, the temperature inside the bottle both the BSS at 18.0 \(\pm\) 0.1 \({}^{\circ}\)C and of the BSS at 2.7 \(\pm\) 0.1 \({}^{\circ}\)C did not change when kept at room temperature or at constant cold temperature using the thermal \"coat\", respectively. Table 3 reports the temperature of the saline solution detected at the outlet of the phacoemulsifier handpiece in the absence of ultrasound (US), under conditions 1 and 2. When the surgery was simulated using the eye model with US for about one minute (twenty seconds at the maximum power of 80 mW and forty seconds at a power of 25 mW), the saline solution temperature increased and its increments were recorded. In particular, the average temperature variation was +2.5 \({}^{\circ}\)C (from 19 \({}^{\circ}\)C to 21.5 \({}^{\circ}\)C) and +0.4 \({}^{\circ}\)C (from 7.4 \({}^{\circ}\)C to 7.8 \({}^{\circ}\)C) for conditions 1 and 2, respectively; the maximum temperature variation was +3.1\({}^{\circ}\)C (from 19 \({}^{\circ}\)C to 22.1 \({}^{\circ}\)C) and +1.0 \({}^{\circ}\)C (from 7.4 \({}^{\circ}\)C to 8.4 \({}^{\circ}\)C) for conditions 1 and 2, respectively. These results are reported in Table 4.  
A preclinical study assessed the reproducibility of the cooling parameters during surgery and confirmed that the temperature variation of BSS solution is smaller when ultrasounds are used together with the cold BSS. It was determined that the temperature increases measured in conditions 1 and 2 would not harm the patients; as such the methodology was applied during \"in vivo\" cataract surgery. The clinical study compared the effects on corneal endothelial cell density (ECD) with two different BSS solution temperatures, used as irrigating solutions during phacoemulsification. Patients of Group A received BSS solution at 18.0 \(\pm\) 0.1 \({}^{\circ}\)C, whereas those of Group B received BSS solution at 2.7 \(\pm\) 0.1 \({}^{\circ}\)C. There were no significant differences in preoperative variables between the two groups, and no surgical complications occurred in any of the patients involved in the study. With regard to ECD, the two groups did not show statistically significant differences in the number of cells per mm\({}^{2}\) (\(p\) = 0.12) before surgery (Figure 1a), whereas the difference was evident comparing ECD data after surgery (Figure 1b). However, intragroup analyses showed a significant decrease between pre- and post- surgery in ECD, both in patients belonging to Group A (\(p\) < 0.001) and Group B (\(p\) < 0.001) (Figure 1). Intergroup analyses revealed that in Group B, ECD was significantly higher than in Group A (\(p\) < 0.001) (Figure 1). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Surgery Condition** & \
\begin{tabular}{c} **Average Temperature Variation** \\ **(\({}^{\circ}\)C) over the Time** \\ \end{tabular} &
\begin{tabular}{c} **Maximum Temperature** \\ **Variation (\({}^{\circ}\)C) over the Time** \\ \end{tabular} & **Time** \\ \hline
1 & +2.5 (from 19 \({}^{\circ}\)C to 21.5 \({}^{\circ}\)C) & +3.1 (from 19 \({}^{\circ}\)C to 22.1 \({}^{\circ}\)C) & 1 min \\ \hline
2 & +0.4 (from 7.4 \({}^{\circ}\)C to 7.8 \({}^{\circ}\)C) & +1.0 (from 7.8 \({}^{\circ}\)C to 8.4 \({}^{\circ}\)C) & 1 min \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The average and the maximum temperature variation for one minute of simulated intervention under conditions 1 and 2. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Surgery Condition** & \
\begin{tabular}{c} **Solution Temperature** \\ **in the Bottle (\({}^{\circ}\)C)** \\ \end{tabular} &
\begin{tabular}{c} **Temperature Output from the** \\ **Handpiece (\({}^{\circ}\)C)** \\ \end{tabular} & **Time** \\ \hline
1 & \(18.0\pm 0.1\) & \(19.0\pm 0.1\) & 4 min \\ \hline
2 & \(2.7\pm 0.1\) & \(7.4\pm 0.1\) & 4 min \\ \hline \hline \end{tabular}
\end{table}