A comparison of accommodation amplitudes in pseudophakic eyes measured with three different methods.

PURPOSE: To compare the accommodative amplitudes with three different methods in pseudophakic eyes with different types of intraocular lenses (IOLs). METHODS: Fifty-one pseudophakic eyes of 44 patients (age: 72.02+/-8.53 years) were studied. One of two different types of IOL were implanted (N=30, three-piece Alcon Acrysof MA60AC and N=21, one-piece Alcon Acrysof SA60AT) in-the-bag after standard phacoemulsification. The time of the examinations was 13.85+/-7.35 months postoperatively. We measured the amplitude of accommodation with three different methods: (1) subjective minus-lenses-to-blur method; (2) a new optical device (ACMaster, Carl Zeiss, Jena, Germany) using partial coherence interference (PCI) technique under physiological stimulus; and (3) objective anterior chamber depth measuring with a standard A-scan ultrasonic device (Ultrascan Imaging System, Alcon Laboratories, Forth Worth, TX, USA) before and after pharmacological relaxation of ciliary muscle. RESULTS: We measured -0.83+/-0.63 D amplitude of accommodation with subjective minus-lenses-to-blur method. The IOL position did not change significantly during physiological accommodation effort measured with PCI method (-0.026+/-0.134 mm). The change in the IOLs position between near fixating and after ciliary muscle relaxation was -0.18+/-0.28 mm measured with ultrasound. There were no significant differences between values of one-piece and three-piece IOL groups. CONCLUSION: The amplitude of accommodation measured by subjective and objective methods are different and are not comparable with each other. We did not observe any difference between values of examined two types of IOLs.

Comparison of divide and conquer and phaco-chop techniques during fluid-based phaco-emulsification.

PURPOSE: To determine whether, similar to ultrasound phaco-emulsification, applied energy and surgery time decrease using phaco-chop nucleus fragmentation method compared to divide and conquer technique using the fluid-based system. METHODS: This prospective, comparative, randomized clinical study included patients with cataract who were randomly assigned to use either standard divide and conquer technique (25 eyes of 25 patients, Group 1) or Nagahara phaco-chop maneuver (25 eyes of 25 patients, Group 2) during fluid-based phaco-emulsification. Surgical parameters were recorded and patients were examined 1 day, 10 days, and 1 month after surgery. Statistical analyses were performed using the paired test of Wilcoxon. RESULTS: Fluid-based time, mean fluid-based magnitude, effective fluid-based time, and the number of pulses were significantly less using phaco-chop technique compared to divide and conquer method (p<0.001). Surgery time was similar using the two nucleofractis techniques (p=0.97). Visual acuities showed no statistical differences between the two groups (p>0.05). CONCLUSIONS: Nuclear fragmentation can be performed with Nagahara phaco-chop technique using the fluid-based system as well. The applied fluid-based energy decreases compared to divide and conquer method. However, surgery time is not reduced due to the difficulties reaching the full occlusion necessary to hold the nucleus during the chop maneuver.

Corneal endothelial function after phacoemulsification using the fluid-based system compared to conventional ultrasound technique.

AIM: To quantitatively assess corneal endothelial changes after phacoemulsification with the fluid-based system compared to conventional ultrasound technique. METHODS: This prospective, randomized clinical study included patients with cataract who were randomly assigned either to have phacoemulsification with the fluid-based system (30 eyes of 30 patients--Group 1) or with traditional ultrasound (30 eyes of 30 patients--Group 2). Patients who were available at each follow-up visit (25 eyes in both groups) were enrolled in the statistical analysis. Endothelial function was evaluated by measuring central corneal thickness, central endothelial cell density (ECD), mean cell size, and coefficient of variation in cell size preoperatively, 10 days, 1 and 3 months, and 1 year after surgery. Statistical analyses were performed using two-way repeated measure ANOVA. RESULTS: An acute, reversible increase of central corneal thickness (CCT) was found 10 days after surgery, which was similar in both groups (P=0.35). ECD decreased, whereas mean cell size increased significantly immediately after surgery. However, the impairments were finished after 1 month. The alterations were similar in both groups (ECD: P=0.99; mean cell size: P=0.85). The coefficient of variation in cell size remained stable after surgery (P=0.08), and significant difference was not found between groups (P=0.99). The endothelial cell loss (ECL) was 6.5+/-8.4% in Group 1 and 6.5+/-11.7% in Group 2 (P=0.69). CONCLUSIONS: Corneal endothelial changes were similar using the fluid-based system compared to the traditional ultrasound technique. The fluid-based method proved to be as safe as conventional ultrasound in cataract surgery.