Stability of a Novel Intraocular Lens Design: Comparison of Two Trifocal Lenses

PURPOSE: To compare visual outcomes, rotational stability, and centration in a randomized controlled trial in patients undergoing cataract surgery who were bilaterally implanted with two different trifocal intraocular lenses (IOLs) with a similar optical zone but different haptic shape. METHODS: Twenty-one patients (42 eyes) with cataract and less than 1.50 D of corneal astigmatism underwent implantation of one FineVision/MicoF IOL in one eye and one POD FineVision IOL in the contralateral eye (PhysIOL, Liège, Belgium) at IOA Madrid Innova Ocular, Madrid, Spain. IOL allocation was random. Outcome measures, all evaluated 3 months postoperatively, included monocular and binocular uncorrected distance (UDVA), corrected distance (CDVA), distance-corrected intermediate (DCIVA), and near (DCNVA) visual acuity (at 80, 40, and 25 cm) under photopic conditions, refraction, IOL centration, haptic rotation, dysphotopsia, objective quality of vision and aberration quantification, patient satisfaction, and spectacle independence. RESULTS: Three months postoperatively, mean monocular UDVA, CDVA, DCIVA, and DCNVA (40 cm) under photopic conditions were 0.04 ± 0.07, 0.01 ± 0.04, 0.15 ± 0.11, and 0.16 ± 0.08 logMAR for the eyes implanted with the POD FineVision IOL and 0.03 ± 0.05, 0.01 ± 0.02, 0.17 ± 0.12, and 0.14 ± 0.08 logMAR for those receiving the FineVision/MicroF IOL. Moreover, the POD FineVision IOL showed similar centration (P > .05) and better rotational stability (P < .05) than the FineVision/MicroF IOL. Regarding halos, there was a minimal but statistically significant difference, obtaining better results with FineVision/MicroF. Full spectacle independence was reported by all patients. CONCLUSIONS: This study revealed similar visual outcomes for both trifocal IOLs under test (POD FineVision and FineVision/MicroF). However, the POD FineVision IOL showed better rotational stability, as afforded by its design.

Asymptotic stability of a coupled Advection-Diffusion-Reaction system arising in bioreactor processes.

In this work, we perform an asymptotic analysis of a coupled system of two Advection-Diffusion-Reaction equations with Danckwerts boundary conditions, which models the interaction between a microbial population (e.g., bacterias), called biomass, and a diluted organic contaminant (e.g., nitrates), called substrate, in a continuous flow bioreactor. This system exhibits, under suitable conditions, two stable equilibrium states: one steady state in which the biomass becomes extinct and no reaction is produced, called washout, and another steady state, which corresponds to the partial elimination of the substrate. We use the method of linearization to give sufficient conditions for the asymptotic stability of the two stable equilibrium configurations. Finally, we compare our asymptotic analysis with the usual asymptotic analysis associated to the continuous bioreactor when it is modeled with ordinary differential equations.

Thermal stability study of AlGaN/GaN MOS-HEMTs using Gd2O3 as gate dielectric

Thermal stability of AlGaN/GaN MOS-HEMTs and -diodes using Gd_(2)O_(3) are investigated by means of different thermal cycles and storage tests up to 500ºC for one week. IV DC and pulsed characteristics of the devices before and after the processes are evaluated and compared with conventional HEMTs. Results show that the devices with Gd_(2)O_(3) dielectric layer have lower leakage current and a more stable behavior during thermal treatment processes compared with conventional devices. In fact, an excellent on/off ratio of about 108 and a stable V_(t) is observed after storage at high temperature. The beneficial effects of Gd_(2)O_(3) on trapping effects of MOS-HEMTs are also dis-cussed.