Fouling mechanisms in anoxic-aerobic sequencing batch membrane bioreactor based on adapted Hermia models and main foulant characteristics.

Various derivatives of Hermia models (complete pore blocking, intermediate pore blocking, cake layer formation, and standard pore blocking) and different assessments of foulant characteristics have long been used to determine the membrane fouling mechanisms. Accordingly, this study aims to adapt Hermia models and their combination according to the operating conditions of an anoxic-aerobic sequencing batch membrane bioreactor (A/O-SBMBR). In addition, fouling mechanisms of the A/O-SBMBR were assessed using these models along with the main foulant characteristics. Models fitting with the transmembrane pressure (TMP) data indicated that the intermediate-standard model was accounting for the increased fouling during the whole regular operating period, with the residual sum of squares (RSS) of 58.3. A more detailed study on the distinct stages of TMP curve showed that the intermediate-standard model had the best fit in stages of 2 and 3, with the RSS equal to 2.6 and 2.8, respectively. Also, the complete-standard model provided the best description of the fouling mechanism in stage 4, with the RSS of 12.5. Different analyzes revealed how the main foulant characteristics affect the occurrence of intermediate, complete and standard fouling mechanisms in the A/O-SBMBR, which is consistent with the fitting results of the adapted Hermia models. The modeling and experimental methods used in the presented study provided a valuable basis to prevent and control membrane fouling in membrane bioreactors.

The Use of Capsular Tension Rings to Reduce Refractive Shift in Patients With Implantation of Trifocal Intraocular Lenses.

PURPOSE: To determine whether use of a capsular tension ring (CTR) can increase refractive stability in patients with implantation of two different trifocal intraocular lenses (IOLs). METHODS: A prospective, consecutive series of eyes underwent refractive lens exchange with implantation of two different trifocal IOL designs: FineVision Micro F (non-toric) and FineVision POD FT (toric) (PhysIOL, Liege, Belgium). Power calculation was determined using the Haigis formula. Refractive lens exchange surgery was performed according to the standard Memira protocol. Refractive results and stability were assessed at 2 weeks and 3 months postoperatively. RESULTS: Three hundred eighty-eight eyes were included in the analysis. Overall, 71% and 76% of MicroF eyes implanted with (n = 139) and without (n = 104) a CTR, respectively, had hyperopic shift; 9% of MicroF eyes with a CTR had a shift of greater than +0.50 to +0.75 or less diopters (D) and 4% had a shift of greater than +0.75 D. In MicroF eyes without a CTR, 12% and 3% of eyes experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. In the POD FT group, 72% and 69% of eyes with (n = 81) and without (n = 64) a CTR, respectively, had hyperopic shift; 10% of POD FT eyes with a CTR had a change of greater than +0.50 to +0.75 D or less and 7% had a shift of greater than +0.75 D. In POD FT eyes without a CTR, 13% and 3% experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. For the MicroF design, the best refractive stability was found in the CTR group and the poorest stability in the non-CTR group (P = .084). For the POD FT design, the best refractive stability was found in the non-CTR group and the poorest stability in the CTR group (P = .297). CONCLUSIONS: Up to 7% of eyes implanted with FineVision trifocal IOLs had a hyperopic shift of greater than +0.75 D approximately 2 weeks to 3 months postoperatively. Using a CTR in MicroF eyes had no statistically significant effect on refractive stability. Placing a CTR with POD FT IOLs appeared to reduce refractive stability, although not significantly. [J Refract Surg. 2017;33(12):802-806.].

Three-year follow-up of posterior capsule opacification with two different silicone intraocular lenses.

PURPOSE: To compare posterior capsule opacification (PCO) after cataract surgery with implantation of two silicone intraocular lenses (IOLs) with different designs. METHODS: We carried out a prospective, clinical study of 116 patients randomized to standardized phacoemulsification with implantation of CeeOn Edge (n = 57) or SI40NB (n = 59) IOLs. The follow-up period was 3 years. To evaluate PCO morphologically, digital images were obtained and analysed using evaluation of posterior capsule opacification computer software (epco). The neodymium:YAG (Nd:YAG) capsulotomy rate was recorded. RESULTS: At 2 and 3 years, the eyes with SI40NB IOLs had significantly more PCO than those with the CeeOn Edge IOLs (p = 0.00014 and p = 0.002). Nine Nd:YAG capsulotomies were performed in the SI40NB group and none in the CeeOn Edge group. This difference was statistically significant (p = 0.003). In some patients a regression of PCO was noticed and confirmed using epco. Statistically less PCO was noted when the capsulorhexis rim was placed so that it covered all 360 degrees of the optic of the IOL. CONCLUSIONS: A clinically and statistically significant difference in PCO development between CeeOn Edge and SI40NB IOLs at 2 and 3 years postoperatively was found. These findings support earlier studies indicating that a sharp edge of the optic is a more important factor in IOL design than IOL material in the prevention of PCO.