Designing and making an open source, 3D-printed, punctal plug with drug delivery system.

With the advancement in the study of keratoconjunctivitis sicca and the scope of its treatment, punctal plugs are being widely used for the therapeutic management of dry eye disease. With the emergence of 3D printing in medicine, 3D printing of punctal plugs that have an inbuilt drug delivery system and also that can be personalized from patient to patient according to their punctum size can be a great therapeutic option. Another benefit of the device is that its printing takes a short period of time and is cost-effective. This study aimed at making an open source design and 3D printing an efficient model of a punctal plug with an inbuilt drug delivery system that can be eventually used for the treatment of various ocular diseases that require frequent drug instillation or blockage of the nasolacrimal pathway. The 3D design for the punctal plug was made using the open source application, FreeCAD, and slicing was done using the application ChituBox. After that, the plugs were printed using the LCD printer Crealty LD-002R. The material used was resin that was compatible with the Crealty LD-002R. Punctal plugs with satisfactory results were printed using the LCD printer. The punctal plugs showed suitable structure and were also easily reproduced in the 3D printer without any complications or setbacks.

In vivo imaging of neuronal calcium during electrode implantation: Spatial and temporal mapping of damage and recovery.

Implantable electrode devices enable long-term electrophysiological recordings for brain-machine interfaces and basic neuroscience research. Implantation of these devices, however, leads to neuronal damage and progressive neural degeneration that can lead to device failure. The present study uses in vivo two-photon microscopy to study the calcium activity and morphology of neurons before, during, and one month after electrode implantation to determine how implantation trauma injures neurons. We show that implantation leads to prolonged, elevated calcium levels in neurons within 150 µm of the electrode interface. These neurons show signs of mechanical distortion and mechanoporation after implantation, suggesting that calcium influx is related to mechanical trauma. Further, calcium-laden neurites develop signs of axonal injury at 1-3 h post-insert. Over the first month after implantation, physiological neuronal calcium activity increases, suggesting that neurons may be recovering. By defining the mechanisms of neuron damage after electrode implantation, our results suggest new directions for therapies to improve electrode longevity.

Controlling levonorgestrel binding and release in a multi-purpose prevention technology vaginal ring device.

Despite a long history of incorporating steroids into silicone elastomers for drug delivery applications, little is presently known about the propensity for irreversible drug binding in these systems. In this study, the ability of the contraceptive progestin levonorgestrel to bind chemically with hydrosilane groups in addition-cure silicone elastomers has been thoroughly investigated. Cure time, cure temperature, levonorgestrel particle size, initial levonorgestrel loading and silicone elastomer type were demonstrated to be key parameters impacting the extent of levonorgestrel binding, each through their influence on the solubility of levonorgestrel in the silicone elastomer. Understanding and overcoming this levonorgestrel binding phenomenon is critical for the ongoing development of a number of drug delivery products, including a multi-purpose technology vaginal ring device offering simultaneous release of levonorgestrel and dapivirine - a lead candidate antiretroviral microbicide - for combination HIV prevention and hormonal contraception.

Dermal permeation of 2-hydroxypropyl acrylate, a model water-miscible compound: effects of concentration, thermodynamic activity and skin hydration.

UNLABELLED: The goal of these studies was to measure and interpret the skin permeability characteristics of 2-hydroxypropyl acrylate (HPA) as a model compound that is completely miscible with water. METHODS: In vitro permeation from HPA-H2O binary mixtures through human epidermis and silicone membranes was measured. Thermodynamic activities of HPA and H2O in these mixtures were determined. Permeation was also measured through epidermis and silicone from donor solutions with constant HPA activity but different H2O activities. Water uptake into desiccated human stratum corneum (SC) equilibrated with HPA-H2O mixtures was determined. RESULTS: Steady-state flux of HPA through silicone was a linear function of HPA activity but not HPA concentration. For epidermis on the other hand, flux increased with HPA activity only for HPA activities ≤ 0.35. At constant HPA activity, flux decreased 4.5-fold as water activity decreased from 1 to 0.8. Incubation of SC with HPA-H2O mixtures resulted in substantial changes in SC water content, dependent on the water activity of the mixture and consistent with measured SC water sorption data. CONCLUSIONS: These experiments provide unequivocal evidence of a substantial increase in epidermal barrier function resulting from SC dehydration. Dehydration-related alterations in the SC appear responsible for the observed flux characteristics.

A simple method for using silicone elastomer masks for quantitative analysis of cell migration without cellular damage or substrate disruption.

Cell migration is fundamental to many biological processes, including development, normal tissue remodeling, wound healing, and many pathologies. However, cell migration is a complex process, and understanding its regulation in health and disease requires the ability to manipulate and measure this process quantitatively under controlled conditions. This report describes a simple in vitro assay for quantitative analysis of cell migration in two-dimensional cultures that is an inexpensive alternative to the classic "scratch" assay. The method described utilizes flexible silicone masks fabricated in the lab according to the research demands of the specific experiment to create a cell-free area for cells to invade, followed by quantitative analysis based on widely available microscopic imaging tools. This experimental approach has the important advantage of visualizing cell migration in the absence of the cellular damage and disruption of the substrate that occurs when the "wound" is created in the scratch assay. This approach allows the researcher to study the intrinsic migratory characteristics of cells in the absence of potentially confounding contributions from cellular responses to injury and disruption of cell-substrate interactions. This assay has been used with vascular smooth muscle cells, fibroblasts, and epithelial cell types, but should be applicable to the study of practically any type of cultured cell. Furthermore, this method can be easily adapted for use with fluorescence microscopy, molecular biological, or pharmacological manipulations to explore the molecular mechanisms of cell migration, live cell imaging, fluorescence microscopy, and correlative immunolabeling.

Microbial biofilms on facial prostheses.

The composition of microbial biofilms on silicone rubber facial prostheses was investigated and compared with the microbial flora on healthy and prosthesis-covered skin. Scanning electron microscopy showed the presence of mixed bacterial and yeast biofilms on and deterioration of the surface of the prostheses. Microbial culturing confirmed the presence of yeasts and bacteria. Microbial colonization was significantly increased on prosthesis-covered skin compared to healthy skin. Candida spp. were exclusively isolated from prosthesis-covered skin and from prostheses. Biofilms from prostheses showed the least diverse band-profile in denaturing gradient gel electrophoresis (DGGE) whereas prosthesis-covered skin showed the most diverse band-profile. Bacterial diversity exceeded yeast diversity in all samples. It is concluded that occlusion of the skin by prostheses creates a favorable niche for opportunistic pathogens such as Candida spp. and Staphylococcus aureus. Biofilms on healthy skin, skin underneath the prosthesis and on the prosthesis had a comparable composition, but the numbers present differed according to the microorganism.

Decreased material-activation of the complement system using low-energy plasma polymerized poly(vinyl pyrrolidone) coatings.

In the current study we investigate the activation of blood complement on medical device silicone rubber and present a plasma polymerized vinyl pyrrolidone (ppVP) coating which strongly decreases surface-activation of the blood complement system. We show that uncoated silicone and polystyrene are both potent activators of the complement system, measured both as activated, deposited C3b and quantifying fluid-phase release of the cleavage fragment C3c. The ppVP coated silicone exhibits approximately 90% reduced complement activation compared to untreated silicone. Quartz crystal microbalance with dissipation (QCM-D) measurements show relatively strong adsorption of blood proteins including native C3 to the ppVP surface, indicating that reduction of complement activation on ppVP is neither a result of low protein adsorption nor lower direct C3-binding, and is therefore possibly a consequence of differences in the adsorbed protein layer composition. The alternative and classical complement pathways are barely detectable on ppVP while the lectin pathway through MBL/ficolin-2 deposition remains active on ppVP suggesting this pathway is responsible for the remaining subtle activation on the ppVP coated surface. The ppVP surface is furthermore characterized physically and chemically using scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR), which indicates preservation of chemical functionality by the applied plasma process. Overall, the ppVP coating shows a potential for increasing complement-compatibility of blood-contacting devices.

Controlling cellular activity by manipulating silicone surface roughness.

Silicone elastomers exhibit a broad range of beneficial properties that are exploited in biomaterials. In some cases, however, problems can arise at silicone elastomer interfaces. With breast implants, for example, the fibrous capsule that forms at the silicone interface can undergo contracture, which can lead to the need for revision surgery. The relationship between surface topography and wound healing--which could impact on the degree of contracture--has not been examined in detail. To address this, we prepared silicone elastomer samples with rms surface roughnesses varying from 88 to 650 nm and examined the growth of 3T3 fibroblasts on these surfaces. The PicoGreen assay demonstrated that fibroblast growth decreased with increases in surface roughness. Relatively smooth (approximately 88 nm) PDMS samples had ca. twice as much fibroblast DNA per unit area than the 'bumpy' (approximately 378 nm) and very rough (approximately 604 and approximately 650 nm) PDMS samples. While the PDMS sample with roughness of approximately 650 nm had significantly fewer fibroblasts at 24h than the TCP control, fibroblasts on the smooth silicone surprisingly reached confluence much more rapidly than on TCP, the gold standard for cell culture. Thus, increasing the surface roughness at the sub-micron scale could be a strategy worthy of consideration to help mitigate fibroblast growth and control fibrous capsule formation on silicone elastomer implants.

The endogenous cannabinoid, anandamide, inhibits dopamine transporter function by a receptor-independent mechanism.

The endocannabinoid, anandamide (AEA), modulates the activity of the dopamine transporter (DAT) in heterologous cells and synaptosomal preparations. The cellular mechanisms mediating this effect are unknown. The present studies employed live cell imaging techniques and the fluorescent, high affinity DAT substrate, 4-(4-(dimethylamino)-styryl)-N-methylpyridinium (ASP(+)), to address this issue. AEA addition to EM4 cells expressing yellow fluorescent protein-tagged human DAT (hDAT) produced a concentration-dependent inhibition of ASP(+) accumulation (IC(50): 3.2 +/- 0.8 microM). This effect occurred within 1 min after AEA addition and persisted for 10 min thereafter. Pertussis toxin did not attenuate the effects of AEA suggesting a mechanism independent of G(i)/G(o) coupled receptors. The amidohydrolase inhibitor, phenylmethylsulfonyl fluoride (0.2 mM), failed to alter the AEA-evoked inhibition of ASP(+) accumulation. Methanandamide (10 microM), a metabolically stable analogue of AEA inhibited accumulation but arachidonic acid (10 microM) was without effect suggesting that the effects of AEA are not mediated by its metabolic products. The extent of AEA inhibition of ASP(+) accumulation was not altered in cells pre-treated with 1 microM URB597, a specific and potent fatty acid amide hydrolase inhibitor, and the cyclooxygenase inhibitor, indomethacin (5 microM) Live cell imaging revealed a significant redistribution of hDAT from the membrane to the cytosol in response to AEA treatment (10 microM; 10 min). Similarly biotinylation experiments revealed that the decrease in DAT function was associated with a reduction in hDAT cell surface expression. These results demonstrate that AEA modulates DAT function via a cannabinoid receptor-independent mechanism and suggest that AEA may produces this effect, in part, by modulating DAT trafficking.

The foreign body reaction in T-cell-deficient mice.

The role(s) of T lymphocytes in the foreign body response has not been thoroughly elucidated. Lymphocytes are known to augment macrophage adhesion and fusion in vitro. Furthermore, T lymphocytes are a possible source of the cytokines, IL-4 and IL-13, which induce macrophage fusion. In this study, we used BALB/c mice and BALB/c (nu/nu) nude mice to investigate foreign body giant cell (FBGC) formation in a T-cell-deficient setting. Mice were implanted with Elasthane 80A (PEU), silicone rubber (SR), or poly(ethylene terephthalate) (PET) for 7, 14, or 21 days using the cage implant system. Exudate cells and IL-4 and IL-13 levels in exudate supernatants were analyzed by flow cytometry and a multiplex immunoassay, respectively, at Days 7, 14, and 21. Macrophage adhesion and fusion on material surfaces were analyzed using optical microscopy. T-cell-deficient mice had lower total leukocyte concentrations at the biomaterial implant site at all time points. Adherent cell density was comparable between normal and T-cell-deficient mice except in the PEU group at Day 21. However, percent fusion, average nuclei per FBGC, and FBGC morphology were comparable between normal and T-cell-deficient mice. IL-4 was not detected in any sample, but IL-13 levels were also comparable between normal and T-cell-deficient mice indicating Th2-polarized T-cells are not the sole source of this cytokine. We have shown that there are pathways that do not require thymus-matured T lymphocytes, which lead to a normal foreign body response to biomaterials in a murine model.

Quantitative in vivo cytokine analysis at synthetic biomaterial implant sites.

To further elucidate the foreign body reaction, investigation of cytokines at biomaterial implant sites was carried out using a multiplex immunoassay and ELISA. Macrophage activation cytokines (IL-1beta, IL-6, and TNFalpha), cytokines important for macrophage fusion (IL-4 and IL-13), antiinflammatory cytokines (IL-10 and TGFbeta), chemokines (GRO/KC, MCP-1), and the T-cell activation cytokine IL-2 were quantified at biomaterial implant sites. Empty cages (controls) or cages containing synthetic biomedical polymer (Elasthane 80A (PEU), silicone rubber (SR), or polyethylene terephthalate (PET)) were implanted subcutaneously in Sprague-Dawley rats for 4, 7, or 14 days, and cytokines in exudate supernatants and macrophage surface adhesion and fusion were quantified. The presence of a polymer implant did not affect the levels of IL-1beta, TGFbeta, and MCP-1 in comparison to the control group. IL-2 was not virtually detected in any of the samples. Although the levels of IL-4, IL-13, IL-10, and GRO/KC were affected by polymer implantation, but not dependent on a specific polymer, IL-6 and TNFalpha were significantly greater in those animals implanted with PEU and SR, materials that do not promote fusion. The results indicate that differential material-dependent cytokine profiles are produced by surface adherent macrophages and foreign body giant cells in vivo.

The adsorption of major tear film lipids in vitro to various silicone hydrogels over time.

PURPOSE: An in vitro study was conducted to measure the adsorption of major tear film lipids to soft contact lenses over time. METHODS: Commercial balafilcon A (PureVision; Bausch & Lomb, Rochester, NY), galyfilcon A (Acuvue Advance; Johnson & Johnson Vision Care), lotrafilcon A and B (Night & Day And O(2)Optix; CIBA Vision, Duluth, GA), senofilcon A (Acuvue Oasys; Johnson & Johnson Vision Care, Jacksonville, FL) and etafilcon A (Acuvue 2; Johnson & Johnson Vision Care) lenses were all soaked for 14 hours in the dark at 34.5 degrees C in either cholesterol (CH; nonpolar lipid) or phosphatidylethanolamine (PE; polar lipid), tagged with 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) and N-fluorescein-5-thiocarbamoyl (FITC) labels, respectively. After rinsing, the lenses were measured for fluorescence and the corresponding lipid concentration was calculated from an appropriate standard curve. The lenses were then placed into a fresh 1-mL aliquot of the lipid being tested, and the procedure was repeated for 20 days. RESULTS: In vitro adsorption of CH was greater that that of PE for all lens types (P < 0.0001 at days 14 and 20). After 20 days of soaking in PE, the lotrafilcon polymers showed the lowest adsorption of all the silicone hydrogel lenses tested at 0.4 and 1.5 microg/lens, for lotrafilcon A (P < or = 0.0001) and lotrafilcon B, respectively (P < or = 0.0001). Galyfilcon A and senofilcon A showed significantly higher PE adsorption at 5.1 and 4.9 microg/lens, respectively, compared with all other silicone hydrogel lenses investigated (P < 0.03). Senofilcon A (P < 0.0001) and balafilcon A (P < 0.02) had the highest affinity for CH of all the lens types after 20 days, with adsorptions of 23.2 and 24.1 microg/lens, respectively. Lotrafilcon B (P < 0.0001) showed the lowest in vitro adsorption of CH of all the lens types, at 3 mug/lens. CONCLUSIONS: In vitro lipid adsorption varied greatly depending on the lens material for both polar and nonpolar lipids. Overall, there was less in vitro adsorption of lipid to the lotrafilcon A and B polymers than for any of the other silicone hydrogel polymers tested. The quantity of lipid adsorption by lotrafilcon polymers was similar to "conventional" hydrogel lenses.

The transient dermal exposure: theory and experimental examples using skin and silicone membranes.

A diffusion model is presented to account for the disposition of chemicals applied to skin as transient exposures. Two conditions are considered that apply to the skin surface following the exposure period, which are applicable to chemicals exhibiting two extremes of chemical volatility. For one case, representing highly volatile compounds, the solution is generalized to apply to multiple transient exposures. For both cases, algebraic expressions are derived to calculate the total amount of chemical that penetrates the skin. The theory is applied to experimental measurements of the in vitro penetration of diethyl phthalate applied to hairless guinea pig (HGP) skin and silicone rubber membranes (SRMs) as transient exposures. The transient exposure theory ably models the experimental data, with coefficients of determination greater than 0.97 (HGP) and greater than 0.99 (SRM). The ability of parameters derived from concurrent infinite dose experiments to predict the time course of absorption from transient exposures is explored. Discrepancies were found between measured cumulative penetration of chemical from transient exposure experiments and penetration predicted from parameters derived from infinite dose experiments, particularly for HGP. Possible reasons are explored. The current model may provide a realistic framework for estimating absorption from occupational, environmental and pharmaceutical dermal exposures.

Interaction with intraocular lens materials: does heavy silicone oil act like silicone oil?

PURPOSE: To determine the interaction of heavy silicone oil with various intraocular lens (IOL) materials and whether heavy silicone oil covers the silicone IOL optic as silicone oil does. SETTING: Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey. METHODS: The study group comprised 5 poly(methyl methacrylate) (PMMA) IOLs, 4 foldable silicone IOLs, 5 foldable hydrophilic acrylic IOLs, and 5 foldable hydrophobic acrylic IOLs. Each IOL was bathed in balanced salt solution (BSS) for 10 minutes and then placed in heavy silicone oil dyed with Sudan Black for another 10 minutes. Afterward, each IOL was reimmersed in BSS for 5 minutes and examined under the light microscope. Digital images were analyzed to determine the optic area covered with heavy silicone oil. RESULTS: The mean heavy silicone oil coverage was 7.05% +/- 7.88% (SD) (range 1.13% to 20.54%) on PMMA IOLs, 100% on silicone IOLs, 12.17% +/- 11.43% (range 1.25% to 31.52%) on hydrophobic acrylic IOLs, and 34.64% +/- 13.28% (range 12.57% to 44.42%) on hydrophilic acrylic IOLs. Heavy silicone oil coverage of silicone IOLs was statistically significantly greater than the coverage of other IOL materials. CONCLUSION: Heavy silicone oil acted the same as silicone oil and covered the entire surface of silicone IOLs.

In vivo fluorescein staining of SI-30NB silicone intraocular lens.

We report a case of a 48-year-old pseudophakic woman who presented 3 weeks after Heidelberg retinal angiography using intravenous sodium fluorescein 2%. Bilateral retinal vasculitis with severe retinal ischemia and extensive capillary dropouts had been diagnosed. Anterior segment examination revealed green staining on the silicone optic of the 3-piece SI-30NB intraocular lens (IOL) (AMO), with no cell or flare in the aqueous humor. The anterior and posterior capsules were not stained. The patient did not report dark vision, double vision, or altered color vision. The anterior and posterior IOL surfaces demonstrated an autofluorescence at the time of fundus photography, which persisted to the 6-week examination although there were no symptoms. This is suggestive of deposits of sodium fluorescein on the IOL surface following angiography.

Kinetics of in vitro lysozyme deposition on silicone hydrogel, PMMA, and FDA groups I, II, and IV contact lens materials.

We sought to compare the kinetics of in vitro lysozyme deposition on silicone hydrogel (SH), polymethyl methacrylate (PMMA), and FDA groups I, II, and IV contact lenses. Lenses were incubated in 125I-labeled lysozyme for time periods ranging from 1 hr to 28 days, and radioactive counts were determined. SH lenses and PMMA deposited less lysozyme than conventional hydrogel lenses (p < 0.05). Lysozyme accumulation on group IV lenses reached a maximum on the seventh day and then plateaued, whereas on groups I, II, and SH lenses, deposition continued to increase across all time periods, reiterating that kinetics of lysozyme deposition is highly material dependent.

Platelet adhesion and protein adsorption on silicone rubber surface by ozone-induced grafted polymerization with carboxybetaine monomer.

Platelet adhesion and protein adsorption on the silicone rubber film grafted with N,N'-dimethyl-N-methacryloyloxyethyl-N-(2-carboxyethyl) ammonium (DMMCA) was studied. The grafting was carried out by means of ozone-induced method and was confirmed by ATR-FTIR and XPS investigations. The grafted films possessed relatively hydrophilic surface revealed by contact angle measurement. The blood compatibility of the grafted film was evaluated in vitro by platelet adhesion in platelet-rich plasma (PRP) and protein absorption in bovine fibrinogen (BFG) using silicone film as the reference. No substantial platelet adhesion was observed for the grafted films incubated in PRP for 60 and 180 min. The protein absorption was also significantly reduced after incubated in bovine fibrinogen for 60 min. Both the results indicated that the blood compatibility of silicone rubber was greatly improved by ozone-induced grafting of carboxybetaine zwitterionic polymer onto its surface.

Polydimethylsiloxane versus polytetrafluoroethylene for vocal fold medialization: histologic evaluation in a rabbit model.

The objective is to study the tissue reaction of the paralyzed vocal cord in response to the injection of particulate plastics in a rabbit model. Forty-five New Zealand rabbits with surgical vocal-fold paralysis were used in the study. Histologic reactions of the larynx and the regional lymph nodes were analyzed by a single blinded pathologist at 6 weeks and 6 months after a vocal-cord injection of Teflon or of silicone elastomer. Macroscopic studies of the liver, lungs, spleen, kidney, and brain were performed. The histological study showed a greater proportion of chronic granulomatous inflammation in animals injected with silicone than in those injected with Teflon. The immunohistochemical study showed a higher degree of phagocytosis of Teflon particles than of the silicone particles. The silicone group presented a more severe fibrous reaction than the Teflon group, but the difference was not significant. No migration particles were found. It is concluded that silicone, having a greater viscosity than Teflon because of the size of its particles, induces more fibrosis and a larger proportion of foreign giant cells in the host. Due to this histological reaction, silicone particles present greater anchorage and stability.

Interaction of intraocular lenses with various concentrations of silicone oil: an experimental study.

The aim of this study was to evaluate the interaction between various widely used intraocular lenses (IOLs) and silicone oils of different viscosities. Four groups of IOLs, including monoblock foldable hydrophilic acrylic IOLs (Morcher, type 92s); monoblock hydrophobic acrylic IOLs (Acrysof-SA60AT, Alcon); single-piece rigid polymethylmethacrylate (PMMA) IOLs (Intraocular Optical International-IOI-65130) and a three-piece foldable silicone optic IOL (CeeOn Edge 911A, Pharmacia UpJohn) were analyzed in vitro to determine the percentage adherence 1,000-centistoke, 1,300-centistoke or 5,000-centistokes silicone oil on the IOL optic. For each IOL type, there was no statistically significant difference in the mean silicone oil coverage (MSC) of the IOL optics for the different viscosities of silicone oil. Silicone IOLs had the highest MSC percentage (79.9%) whereas hydrophilic acrylic IOLs were the least silicone-covered IOLs (7.8%) compared to the other IOL types tested in this study. It is not the concentration of silicone oil that affects silicone oil coverage. When performing small-incision cataract surgery in patients who may require silicone oil injection, foldable hydrophilic acrylic or hydrophobic acrylic lenses should be preferred over standard foldable silicone lenses.

Elapsed time for capsular apposition to intraocular lens after cataract surgery.

OBJECTIVE: To examine when the anterior and posterior lens capsule completely become apposed to optics of silicone and acrylic intraocular lenses (IOLs) implanted after cataract surgery and to determine whether the different IOL materials influence the timing of completion of capsular contact. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: Seventy eyes of 70 patients who were scheduled to undergo cataract surgery were randomly assigned to two groups using random number tables based on the type of IOL implanted: silicone or acrylic. Thirty-two patients in each group completed the follow-up. INTERVENTION: All eyes underwent phacoemulsification surgery with implantation of either a silicone or acrylic IOL. All IOLs were accurately placed into the capsular bag. MAIN OUTCOME MEASURES: Contact of the anterior and posterior lens capsule with the IOL optic surface was evaluated using the Scheimpflug videophotography system at 3, 5, 7, 9, 11, 14, 21, and 28 days after surgery. The postoperative day at which each capsule was completely apposed to the IOL optic was determined. In addition, anterior chamber depth was also measured. RESULTS: The anterior capsule was in contact with the IOL optic on the same day or earlier than the posterior capsule in all patients. Complete apposition of the IOL was observed significantly earlier with silicone IOLs than with acrylic IOLs with both the anterior capsule (6.2 versus 3.6 postoperative days; P < 0.0001) and the posterior capsule (11.1 versus 7.4 postoperative days; P = 0.0339). No significant change in mean anterior chamber depth was observed with the silicone IOL, whereas there was significant anterior shift after implantation of the acrylic IOL. CONCLUSIONS: Capsular contact with the IOL optic is completed within approximately 8 days after cataract surgery with silicone IOLs and 11 days with acrylic IOLs. Complete apposition to both the anterior and posterior capsule was significantly earlier with silicone IOLs than with acrylic IOLs.