Electroless Deposition of Silver onto Silica Nanoparticles to Produce Lipophilic Core-Shell Nanoparticles.

HYPOTHESIS: The colloidal stability of noble metal nanoparticles can be tuned for solvents of varying hydrophobicity by modifying the surface chemistry of the particles with different capping agent architectures. Challenges arise when attempting to separately control multiple nanoparticle properties due to the interdependence of this adsorption process on the surface chemistry and metal architecture. A surfactant-mediated, templated synthesis strategy should decouple control over size and stability to produce lipophilic nanoparticles from aqueous reagents. EXPERIMENTS: A modified electroless plating process that produces oil-dispersible core-shell silver-silica nanoparticles is presented. Amine-terminated alkanes are utilized as the capping agents to generate lipophilic surface coatings and the particles are temporarily stabilized during the synthesis by adding a Pluronic surfactant that enhances dispersibility in the aqueous reaction medium. The evolution of shell morphology, composition, and colloidal stability was analyzed against capping agent architecture and concentration. The role of particle shape was also tested by interchanging the template geometry. FINDINGS: The capping agents installed on the silver shell surface displayed both colloidal stability enhancements and a minimum effective capping concentration that is a function of molecular weight without influencing the shell composition. Particle geometry can be controlled by interchanging the silica template size and shape.

Evaluation of anterior capsular contraction syndrome after cataract surgery with commonly used intraocular lenses.

PURPOSE: The purpose of this study was to compare the incidence of anterior capsular contraction syndrome (ACCS) in cataract patients after implantation with one of two most commonly used hydrophobic acrylic lenses. SETTING: This study included patients from Loma Linda University, Loma Linda, CA, USA. DESIGN: This study is a retrospective chart review. METHODS: In this study, 1,047 eyes of 811 patients with and without known ACCS risk factors who underwent successful phacoemulsification and intraocular lens (IOL) implantation were included. Eyes that sustained intraoperative capsular tears and patients with a postoperative follow-up of <1 month were excluded. Each patient underwent surgery by the same surgeon receiving either the SN60WF IOL or the ZCB00 IOL. The duration of postoperative follow-up along with the presence of ACCS and the dimensions of the anterior capsule opening in these cases were recorded. The incidence of ACCS between the two lenses was compared. RESULTS: ACCS was significantly (P=0.045) less frequent in those patients who received the ZCB00 lens compared to those who received the SN60WF lens, despite a significantly greater (P<0.0001) number of patients with ACCS risk factors in the ZCB00 cohort. CONCLUSION: In a direct comparison of the ZCB00 and SN60WF IOLs, a lower incidence of ACCS was found with ZCB00 IOL.

Intraoperative cyclorotation and pupil centroid shift during LASIK and PRK.

PURPOSE: To determine the degree of cyclorotation and centroid shift in the x and y axis that occurs intraoperatively during LASIK and photorefractive keratectomy (PRK). METHODS: Intraoperative cyclorotation and centroid shift were measured in 63 eyes from 34 patients with a mean age of 34 years (range: 20 to 56 years) undergoing either LASIK or PRK. Preoperatively, an iris image of each eye was obtained with the VISX WaveScan Wavefront System (Abbott Medical Optics Inc) with iris registration. A VISX Star S4 (Abbott Medical Optics Inc) laser was later used to measure cyclotorsion and pupil centroid shift at the beginning of the refractive procedure and after flap creation or epithelial removal. RESULTS: The mean change in intraoperative cyclorotation was 1.48±1.11° in LASIK eyes and 2.02±2.63° in PRK eyes. Cyclorotation direction changed by >2° in 21% of eyes after flap creation in LASIK and in 32% of eyes after epithelial removal in PRK. The respective mean intraoperative shift in the x axis and y axis was 0.13±0.15 mm and 0.17±0.14 mm, respectively, in LASIK eyes, and 0.09±0.07 mm and 0.10±0.13 mm, respectively, in PRK eyes. Intraoperative centroid shifts >100 µm in either the x axis or y axis occurred in 71% of LASIK eyes and 55% of PRK eyes. CONCLUSIONS: Significant changes in cyclotorsion and centroid shifts were noted prior to surgery as well as intraoperatively with both LASIK and PRK. It may be advantageous to engage iris registration immediately prior to ablation to provide a reference point representative of eye position at the initiation of laser delivery.

Scleral fixation of a subluxated intraocular lens-capsular bag complex through a fibrotic continuous curvilinear capsulorhexis.

UNLABELLED: Several strategies have been devised to manage in-the-bag intraocular lens (IOL) subluxation. We describe a method of fixating the IOL-capsular bag complex to the sclera using the fibrotic ring that develops around the continuous curvilinear capsulorhexis (CCC). Two, preferably 3, double-armed 10-0 polypropylene sutures are passed around the fibrotic CCC rim of the capsule and out the Hoffman scleral pockets and then tied in the scleral tunnels to center the IOL-bag complex. This technique provides an alternative approach to repositioning and fixating the IOL-bag complex that is especially useful in cases in which removal and replacement of the IOL would be difficult. It also provides more than 2-point fixation to achieve perfect IOL centration. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.