RESUMO
Purpose: Comparison of three ultrasound (US) frequencies for phacoemulsification of hard cataracts to determine a frequency that makes phacoemulsification more efficacious and safer. Methods: A randomized controlled trial was undertaken at a medical college and hospital. In total, 207 patients with grade 5.6� 6.9 (LOCS III) senile cataract were randomized into three groups. Group I underwent phacoemulsification with 28?kHz frequency, group II with 42?kHz frequency, and group III with 53?kHz frequency. The effective phacoemulsification time (EPT) and estimated fluid usage (EFU) were compared intraoperatively. The endothelial cell parameters were analyzed for 6 months. Results: The groups were matched for age (P = 0.467), gender (P = 0.497), nuclear grade (P = 0.321), and anterior chamber depth (P = 0.635). The EPT and EFU were significantly lower in group III, compared to group II and group I, with P < 0.0001 and P < 0.0001, respectively. Postoperatively, the endothelial cell density (ECD) was significantly higher in group III at 1 month (P < 0.0001), 3 months (P < 0.0001), and 6 months (P < 0.0001). The percentages of ECD loss were also significantly lower in group III; the difference was statistically significant (P < 0.0001) up to 6 months postoperatively. Conclusion: Higher frequency ultrasound was associated with a lower EPT and EFU as well as better endothelial preservation than lower frequencies in hard cataracts
RESUMO
Background: Phacoemulsification is a state of art technique with a steep learning curve the configuration of the phacotip affects the efficacy and execution of the nuclear chopping techniques. Inadequate penetration of phacotip may result in partial thickness nuclear cleavage with residual posterior plane and over enthusiastic penetration may result in posterior capsule rupture. This may be avoided if some estimate can be made preoperatively of the depth of penetration required to achieve full thickness crack.Methods: A total of 60 eyes of 60 patients with age related cataract with grade 4.0 to 6.9 (LOCS III) fulfilling the inclusion and exclusion criteria were included in the study after written informed consent. They were divided into two groups A and B with 30 patients each randomly using envelope method and were operated using conventional and calibrated phacotips respectively and the number of attempts required to achieve complete nuclear chop was noted.Results: In group A, vertical chop was safely and effectively done is 23 patients in just one attempt while it took 2 attempts in 6 patients and 3 attempts in 1 patient. In group B, it took just one attempt in 26 patients while 2 attempts were required in 4 patients. The two groups were comparable (p value 0.453) and was found to be statistically significant.Conclusions: With the use of a calibrated phacotip, the surgeon already knows to what depth he has to penetrate the tip into the center of nucleus depending upon the grade of cataract which results in safe and effective chop in minimum attempts where as in the conventional phacotip, it is more of a blind process. Hence the calibrated phacotip has taken the guess work out of question.