Intraoperative performance and postoperative outcome comparison of longitudinal, torsional, and transversal phacoemulsification machines.

PURPOSE: To compare the intraoperative performance and postoperative outcomes of 3 phacoemulsification machines that use different modes. SETTING: Kensington Eye Institute, Toronto, Ontario, Canada. DESIGN: Comparative case series. METHODS: This chart and video review comprised consecutive eligible patients who had phacoemulsification by the same surgeon using a Whitestar Signature Ellips-FX (transversal), Infiniti-Ozil-IP (torsional), or Stellaris (longitudinal) machine. RESULTS: The review included 98 patients. Baseline characteristics in the groups were similar; the mean nuclear sclerosis grade was 2.0 ± 0.8. There were no significant intraoperative complications. The torsional machine averaged less phacoemulsification needle time (83 ± 33 seconds) than the transversal (99 ± 40 seconds; P=.21) or longitudinal (110 ± 45 seconds; P=.02) machines; the difference was accentuated in cases with high-grade nuclear sclerosis. The torsional machine had less chatter and better followability than the transversal or longitudinal machines (P<.001). The torsional and longitudinal machines had better anterior chamber stability than the transversal machine (P<.001). Postoperatively, the torsional machine yielded less central corneal edema than the transversal (P<.001) and longitudinal (P=.04) machines, corresponding to a smaller increase in mean corneal thickness (torsional 5%, transversal 10%, longitudinal 12%; P=.04). Also, the torsional machine had better 1-day postoperative visual acuities (P<.001). CONCLUSIONS: All 3 phacoemulsification machines were effective with no significant intraoperative complications. The torsional machine outperformed the transversal and longitudinal machines, with a lower mean needle time, less chatter, and improved followability. This corresponded to less corneal edema 1 day postoperatively and better visual acuity.

Comparing a traditional single optotype visual acuity test with a computer-based visual acuity test for childhood amblyopia vision screening: a pilot study.

OBJECTIVE: To investigate the effectiveness of a traditional flip-chart optotype test, the Sheridan Gardiner test (SGT), in measuring visual acuity and detecting amblyopia, compared with a free, computer-based test (CBT), LazyeyeTest.org. DESIGN: Prospective, masked, cross-over study. PARTICIPANTS: Seventy kindergarten-aged children from a downtown Toronto elementary school enrolled in the Kids2See vision screening program. METHODS: Visual acuity in the children was measured monocularly using both tests. The visual acuity results, number of referrals, and outcomes of referrals were compared, as was the usability from the perspective of the child and the vision screener. RESULTS: The children were more likely to score low visual acuity values with the CBT, a result predicted by the existence of crowding bars on the CBT's optotypes. The CBT referred an extra 5 children than the SGT, and of the 4 who saw an ophthalmologist 2 had amblyopia. The SGT referred one child not referred by the CBT. The Cohen's kappa coefficient was 0.67 and the difference in referral rates was not significant (p = 0.13). Relative to the SGT, the sensitivity of the CBT was 88%, specificity was 92%, positive predictive value was 58%, and negative predictive value was 98%. The CBT appeared to be easier and more efficient to administer, more stimulating, and was preferred by the children. CONCLUSIONS: Replacing the SGT with LazyeyeTest.org would increase the efficiency and likely the sensitivity of amblyopia screening. Further research is warranted to confirm the outcomes and to determine if the CBT can be administered accurately by lay screeners.