Comparison of conventional phacoemulsification technique VS. cool phacoemulsification technique with the importance of phacoemulsification variables

ABSTRACT

To compare the efficacy and outcome after cool phacoemulsification with conventional phacoemulsification techniques in terms of effective phacoemulsification time [EPT], wound size and operative complications along with other variables used for the technique. Randomized controlled clinical trial [RCCT]. Ophthalmology Unit III, Sindh Government Lyari General Hospital and DUHS and Al Noor Eye Hospital, Karachi, from January to December 2008. One hundred eyes with nuclear/cortico-nuclear cataract on LOCS III [Lens Opacities Classification System III] underwent phacoemulsification. Fifty eyes were randomized to have surgery by standard phacoemulsification technique and the other 50 eyes by cool phacoemulsification technique. Efficacy and outcomes were judged in terms of variables like effective phaco time, vacuum and power used, quantity of Ringer's lactate solution used and corneal burn. The results between the two groups were compared. Among the phaco variables, the vacuum used in all cases ranged from 100 to 200 mmHg in group A with mean vacuum of 145.3 +/- 29.6 and 300 to 350 mmHg with mean value of 325.8 +/- 14.5 in group B at phaco II [p<0.001]. There was a significant difference in amount of Ringer's lactate used during surgery with 100-180 ml in conventional phacotechnique as opposed to 75-150 ml in cool phacoemulsification [p<0.001]. EPT in group A was between 30 to 180 seconds with mean of 111.3 +/- 40.4 seconds while in group B, it ranged between 2 to 12 seconds with mean of 6.1 +/- 2.92 seconds [p<0.001]. Rate of intra operative complications was lower in cool phacoemulsification [2%] as compared with conventional technique [18%, p=0.008]. Cool phacoemulsification is a safe technique to operate cataract of all grades. It seems to be superior as it reduces effective phaco time, less operative and postoperative complications and is, therefore, safer for the cornea especially with regard to corneal wound burn. However, significantly greater amount of vacuum is needed