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Aim To compare intraocular lens (IOL) calculation methods not requiring refraction data prior to myopic laser-assisted in situ keratomileusis (LASIK) and radial keratotomy (RK). Methods In post-LASIK eyes, the methods not requiring prior refraction data were Hagis-L; Shammas; Barrett True-K no-history; Wang-Koch-Maloney; 'average', 'minimum' and 'maximum' IOL power on the American Society of Cataract and Refractive Surgeons (ASCRS) IOL calculator. Double-K method and Barrett True-K nohistory, 'average', 'minimum' and 'maximum' IOL power on ASCRS IOL calculator were evaluated in post-RK eyes. The predicted IOL power was calculated with each method using the manifest postoperative refraction. Arithmetic and absolute IOL prediction errors (PE) (implanted-predicted IOL powers), variances in arithmetic IOL PE and percentage of eyes within ±0.50 and ±1.00 D of refractive PE were calculated. Results Arithmetic or absolute IOL PE were not significantly different between the methods in post-LASIK and post-RK eyes. In post-LASIK eyes, 'average' showed the highest and 'minimum' showed the least variance, whereas 'average' and 'minimum' had highest percentage of eyes within ±0.5 D and 'minimum' had the highest percentage of eyes within ±1.0 D. In the post-RK eyes, 'minimum' had highest variance, and 'average' had the least variance and highest percentage of eyes within ±0.5 D and ±1.0 D. Conclusion In post-LASIK and post-RK eyes, there are no significant differences in IOL PE between the methods not requiring prior refraction data. 'Minimum' showed least variance in PEs and more chances of eyes to be within ±1.0 D postoperatively in post-LASIK eyes. 'Average' had least variance and more chance of eyes within ±1.0 D in post-RK eyes. [ABSTRACT FROM AUTHOR]

Purpose: To compare real-time intraocular pressure (IOP) response to occlusion break event in 2 phacoemulsification systems. Setting: Iladevi Cataract and IOL Research Center, India. Design: Randomized, experimental study. Methods: Rabbits were randomized to:Group I (n = 10 eyes), Centurion Vision system with active fluidics, or, Group II (n = 10 eyes), Centurion with Active Sentry. Within each group, parameter set 1 (IOP 30 mm Hg, aspiration flow rate [AFR] 20 mL/min, and vacuum 600 mm Hg) and parameter set 2 (IOP 50 mm Hg, AFR 25 mL/min, and vacuum 600 mm Hg) were tested. Real-time rate of drop and rise of IOP after occlusion break event (mm Hg per second) and percentage reduction of IOP from maximum during nuclear fragment removal were compared. Results: 10 rabbits (20 eyes) were included. Rate of drop of IOP after occlusion break was not significantly different between groups. Rate of rise of IOP was statistically significantly higher in Group II with both parameter sets (199.09 +/- 69.28 vs 94.33 +/- 45.66 in parameter set 1, P =.006; and 256 +/- 45.05 vs 165.25 +/- 51.80 in parameter set 2, P =.005), suggesting faster recovery to baseline IOP after occlusion break. The mean percentage reduction of IOP from maximum was significantly higher in Group I (P =.003). Conclusions: Rise of IOP to baseline after occlusion break event was faster and mean percentage reduction of IOP from maximum during nuclear fragment removal was lower when using the Centurion Vision system with the Active Sentry upgrade compared with the traditional handpiece. The ability to sense IOP at the level of the handpiece with the Active Sentry upgrade allows faster mitigation of surge response. [ABSTRACT FROM AUTHOR]