Impact of dimensional variability of primary packaging materials on the break-loose and gliding forces of prefilled syringes.

A prefilled syringe (PFS) should be able to be adequately and consistently extruded during injection for optimal safe drug delivery and accurate dosing. To facilitate appropriate break-loose and gliding forces (BLGF) required during injection, certain primary packaging materials (PPM) such as the syringe barrel and plunger are usually coated with silicone oil, which acts as a lubricant. Due to its direct contact with drug, silicone oil can increase the number of particles in the syringe, which could lead to adverse interactions. Compliance with regulatory defined silicone oil quantities in certain drug products, such as ophthalmic, presents a trade-off with the necessity for desirable low and consistent BLGF. In addition to its siliconization, the dimensional accuracy of PPM has an important role in controlling BLGF. The dimensions of PPM are individualized depending on the product and its design and have certain tolerances that must be met during manufacturing. Most studies on ophthalmic focused on the adverse interactions between silicone oil and the drug. To the authors' knowledge, there have been no public studies so far that have investigated the impact of the dimensional variability of PPM on the BLGF in ophthalmic PFS. In this study, we applied advanced optical shaft and tactile measuring technologies to investigate this impact. The syringes investigated, were first sampled during aseptic production, and tested for BLGF. Subsequently, defined dimensions of PPM were measured individually. The results showed that the dimensional variability of PPM can have a negative impact on the BLGF, despite their conformity to specifications, which indicates that the currently available market quality of PPM is improvable for critical drug products such as ophthalmic. This study could serve as an approach to define product-specific requirements for primary packaging combinations and thus appropriate specifications based on data during the development stage of drug products.

Axial length adjustment in eyes with silicone oil endotamponade reduces overestimation by a swept-source optical coherence tomography-based biometer.

BACKGROUND: To assess changes in ocular biometry of the phakic eye after pars-plana-vitrectomy (PPV) and silicone oil (SO) endotamponade in eyes with a retinal detachment. METHODS: This retrospective, consecutive case series included 72 eyes of 72 patients who underwent PPV with 5000-centistokes SO endotamponade between July 2018 and June 2023. Pseudophakic eyes and eyes with a combined phacovitrectomy were excluded. Primary endpoints were keratometry values, anterior chamber depth (ACD), lens thickness (LT), horizontal corneal diameter (HCD), and axial length (AL) measured by swept-source optical coherence tomography-based biometry (IOLMaster 700) preoperatively and six weeks postoperatively. A recently described formula was used to adjust the AL (aAL) in eyes with SO endotamponade and a theoretical intraocular lens (IOL) calculation was performed. RESULTS: The mean age was 62.1 ± 8.3 years (range: 37-85). After PPV with SO fill, there was an increase in Kmean (0.19 ± 0.51D), while ACD (0.05 ± 0.13 mm), LT (0.03 ± 0.14 mm), and HCD (0.02 ± 0.24 mm) decreased. Preoperatively, the mean AL was 25.22 ± 1.78 mm, while postoperatively the AL was overestimated by 0.12 ± 0.42 mm on average (p = 0.04). By adjusting the AL, the mean difference could be reduced to -0.002 ± 0.41 mm. The aAL resulted in a difference in the refractive outcome in eyes with an AL > 25 mm of 0.34 ± 0.10D in the IOL calculation. CONCLUSIONS: While changes in biometry after PPV with SO endotamponade in the anterior segment are clinically less relevant, a considerable overestimation of AL with IOLMaster 700 was found. We recommend the use of a recently introduced formula for adjusting AL in eyes with SO, allowing overestimation to be minimised considerably.

Development of Multifunctional Hybrid Coatings (Mechanically Resistant and Hydrophobic) Using Methyltrimethoxysilane-Diethoxydimethylsilane-Tetraethoxysilane Mixed Systems.

For many industrial applications, the simultaneous presence in a material of different functional properties is necessary. The main interest lies in making a single material more versatile and durable, less fragile and more efficient. In this study, two concomitant properties in the same material were mainly studied: resistance to cracking and the increase in its hydrophobic properties. The chosen process was the sol-gel route due to its versatility and the ease of formulating materials from various precursors in order to obtain (multi)functional materials. In this paper, sol-gel coatings were prepared with tetraethoxysilane, methyltrimethoxysilane and diethoxydimethylsilane as precursors. Tetraethoxysilane was mainly used to improve the material's mechanical properties, especially hardness, and silicon oil was added to improve its hydrophobic behavior. The integration of silicon oil was monitored via 29Si NMR. Microstructural characterizations were carried out to correlate the multi-scale properties with the microstructure of the derived films. Young's modulus and hardness were measured to highlight the effect of key formulation parameters on the mechanical strength of the coatings. The synergistic effect of these precursors is underlined as well as the beneficial effect of silicon oil (generated in situ or precondensed).

Aqueous misdirection syndrome post silicone oil removal in a vitrectomized eye - a case report.

PUROPSE: Aqueous misdirection syndrome (AMS) is an aggressive post-operative glaucoma unresponsive to conventional measures with grave outcomes. In this report, we describe a rare case of AMS following silicon oil removal in a vitrectomized eye. METHODS: A diabetic patient with tractional retinal detachment underwent pars plana vitrectomy with silicon oil injection. Following retinal reattachment, silicon oil removal was performed at three months. Post oil removal she developed increased intraocular pressure with shallowing of both the peripheral and central anterior chamber suggestive of AMS. RESULTS: Initial medical management with anti-glaucoma medications and cycloplegics was not beneficial. A pars plana lensectomy with complete anterior hyaloidectomy along with a surgical peripheral iridectomy helped relieve the aqueous misdirection. CONCLUSION: AMS can rarely occur following vitrectomy and is likely secondary to intact anterior hyaloid. Lensectomy along with zonulo-hyaloido-iridectomy is essential. This report highlights the occurrence of this rare complication and its effective management.

Combining Perfluorobutylpentane (F4H5) with Glaucoma Drainage Device Implantation for Silicone Oil-Induced Glaucoma: A Pilot Study.

Objectives: Our aim was to perform a perfluorobutylpentane (F4H5) washout in conjunction with glaucoma drainage device (GDD) placement in patients with silicone oil (SO)-induced glaucoma. In this report we present our preliminary results concerning the effectiveness in clearing the SO and the safety of the procedure. Materials and Methods: Eight patients who previously underwent pars plana vitrectomy with SO tamponade due to retinal detachment were selected. Removal of SO was performed on average 10 months after initial surgery. All patients developed glaucoma with evidence of SO remnants in the anterior chamber (AC) and angle. Removal of the remaining SO with F4H5 washout was performed in all cases with concomitant insertion of a GDD to treat the refractory glaucoma. Intraocular pressure (IOP), SO remnants, endothelial cell count, and need for glaucoma medications were evaluated up to 12 months after the surgical procedure. Results: All patients had uneventful surgery with no major complications 12 months postoperatively. A marked reduction of SO remnants in the AC and angle was observed in all cases after surgery. There was a 60.9% decrease in mean IOP 12 months postoperatively (p<0.05) and the need for glaucoma medication was lower in all patients (mean topical medicines: 4 preoperatively vs. 0.75±0.89 postoperatively; p<0.05). Endothelial cell density showed no significant change (mean 2012±129 cells/mm2 preoperatively vs. 1985±134 cells/mm2 postoperatively; p>0.05), and there were no signs of corneal edema. Conclusion: F4H5 is an effective emulsifier for removing SO remnants and may be safely used in conjunction with GDD placement in order to control IOP in eyes with silicone oil-induced glaucoma.

A Rare Complication Causing Another Rare Complication: Corneal Dellen with Infiltration Secondary to Subconjunctival Silicon Oil.

The usage of silicon oil (SO) in vitreoretinal surgery is associated with potential complications. One such complication is the extravasation of SO into the subconjunctival space through open sclerotomies. Subconjunctival SO (SCSO) can cause irregularities in the ocular surface which predisposes to complications like corneal dellen. This corneal dellen can get infected in rare situations. SCSO needs to be removed to stabilize the ocular surface. We present a case of corneal dellen with infiltration which developed as a consequence of SCSO and its management.

Use of Heavy Silicon Oil as Intraocular Tamponade for Inferior Retinal Detachment Complicated by Proliferative Vitreoretinopathy: A Multicentric Experience.

INTRODUCTION: This is a multicentric study on the use of heavy silicon oil (HSO) as an intraocular tamponade for inferior retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR). METHODS: 139 eyes treated for RD with PVR were included in the study. 10 (7.2%) were affected by primary RD with inferior PVR, while 129 (92.8%) were affected by recurrent RD with inferior PVR. 102 eyes (73.9%) had received a silicon oil (SO) tamponade in a previous intervention prior to receiving HSO. Mean follow-up was 36.5 (standard deviation = 32.3) months. RESULTS: The median interval between HSO injection and removal was 4 months (interquartile range: 3). At the time of HSO removal, the retina was attached in 120 eyes (87.6%), whereas in 17 eyes (12.4%), it had re-detached while the HSO was in situ. 32 eyes (23.2%) showed recurrent RD. A subsequent RD relapse was observed in 14.2% of cases with no RD at the time of HSO removal, and in 88.2% if an RD was present at the time of HSO removal. Advancing age showed a positive association with retinal attachment at the end of follow-up, while the risk of RD relapse at the end of the follow-up showed a significant negative association with HSO tamponade duration and with the use of SO rather than air or gas as post-HSO tamponade materials. Mean best corrected visual acuity was 1.1 logarithm of minimum angle of resolution at all follow-up time points. 56 cases (40.3%) needed treatment for elevated intraocular pressure (IOP), with which no clinically relevant variables were associated during follow-up. CONCLUSION: HSO represents a safe and effective tamponade in cases of inferior RD with PVR. The presence of RD at the time of HSO removal is a negative prognostic factor for the development of a subsequent RD relapse. According to our findings, in cases of RD at the time of HSO removal, a short-term tamponade should definitely be avoided, in favor of SO. Special attention must be paid to the risk of IOP elevation, and patients should be closely monitored.

Micropulse Transscleral Cyclophotocoagulation Results in Secondary Glaucoma.

The aim of this study was to analyze the long-term outcome of first session of micropulse transscleral cyclophotocoagulation (MP-CPC) for refractory glaucoma developed after vitreoretinal surgery combined with silicone oil implantation. The inclusion criteria of this consecutive case series were: patients with secondary glaucoma in the refractory stage who underwent MP-CPC between 2018 and 2021, vitreoretinal surgery combined with silicon oil implantation, and at least a 24-month follow-up period after MP-CPC. Success was defined as the baseline eye pressure reduced at least 20%, and it should be ranged between 10 to 20 mmHg without further MP-CPC at the end of the follow-up. For this retrospective study, 11 eyes of 11 patients were selected. The reduction in IOP was found to be significant (p = 0.004) at the end of the follow-up time, and the success rate was 72% according to our results. The change in the number of antiglaucoma agents in the administered eyedrops was not significant compared to the baseline values. At the end of the follow-up period the change in BCVA values was not significant (p = 0.655). Our results confirm significant IOP lowering effect of this subthreshold method preserving visual performance safely even in eyes with previous vitrectomy surgery with a silicone oil implantation.

Pupillary block glaucoma due to anterior migration of nonemulsified silicone oil in a phakic patient: A case report and review of literature.

This report describes a case of acute pupillary block glaucoma related to migration of nonemulsified silicone oil into the anterior chamber (AC) in a young phakic patient. A 24-year-old male diabetic patient underwent uneventful left eye pars plana vitrectomy (PPV) with silicon oil endotamponade for diabetic macula-off tractional retinal detachment. Two weeks after discharge, he presented with severe left eye pain. Examination revealed hand motion vision, high intraocular pressure (IOP) of 67 mmHg with ciliary injection, corneal edema, and two large nonemulsified silicone oil bubbles in the AC at the pupillary margin. Medical management with topical antiglaucoma medications (AGMs) and intravenous acetazolamide and mannitol failed to reduce the IOP. The patient underwent left eye PPV, silicone oil removal, and AC wash. IOP was eventually controlled after the operation without AGM. Pupillary block glaucoma after silicone oil injection is well recognized in aphakic patients, but ophthalmologists should be aware that it can occur in phakic and pseudophakic patients, particularly in complicated cases and patients with a weakness of the iris-lens diaphragm.

Macular Parameters Change during Silicon Oil Tamponade for Retinal Detachment Surgery.

Background and Objectives: To evaluate possible changes in macular thickness parameters during and after silicon oil tamponade and in pars plana rhegmatogenous retinal detachment surgery. Materials and Methods: Our retrospective study included 34 consecutive patients who underwent 23-gauge retinal detachment surgery with silicon oil tamponade. Central macular thickness (CMT), central macular volume cube (CMV) and average macular thickness cube (AVG) were measured by optical coherence tomography (OCT) before rhegmatogenous retinal detachment surgery with silicon oil tamponade during tamponade (seven days, one month and three months after surgery), and one month after silicon oil removal. Results: In our sample, macular parameters CMT, CMV and AVG in patients who underwent retinal detachment surgery were statistically reduced during silicon oil tamponade (p < 0.05). After silicon oil removal, all parameters recovered, reaching numeric values which were not statistically significant compared to preoperative values. The average span of silicon oil tamponade was 162 +/- 23 days. Conclusions: Silicon oil tamponade during 23-gauge rhegmatogenous retinal detachment surgery leads to a transitory reduction of central macular thickness, central macular volume cube and average macular thickness cube in eyes that underwent retinal surgery. After silicon oil removal, macular parameters returned to preoperative values in most of the patients.

Surgical Audit for the Outcome of Primary Rhegmatogenous Retinal Detachment Repair in the Kingdom of Bahrain.

PURPOSE: The purpose of the study was to audit the primary and final success rate for primary rhegmatogenous retinal detachment (RRD) surgery performed between 2017 and 2022 at the Department of Ophthalmology in Salmanyia Medical Complex, the Kingdom of Bahrain. In addition, secondary outcomes for our study include assessments of risk factors for recurrence, final visual outcomes and complication rates. METHODS: Prospective observational study showed data analysis of case series for 75 RRD patients operated during the study period. All patients who met the inclusion criteria were included in the study and evaluated by a specialized vitreoretinal surgeon before and after their operation. All patients were operated by the same surgeon (M.A) in the study period. Data collected from the hospital's electronic medical recording system (I-Seha) include macular state, pre- and postoperative best-corrected visual acuity, duration of symptoms, the presence of proliferative vitreoretinopathy (PVR), retinal breaks and their locations, any ocular comorbidities associated in the perioperative period such as increase in intraocular pressure or development of cataract, and operative notes related to the type of primary, secondary, and tertiary surgery if needed. RESULTS: A total number of 70 eyes from 70 patients with the majority of male patients (74.28%, n = 52) were included in the study. The mean age of the participants was 54.75 years (range: 11-91 years). Most of the patients 48.57% presented within 6 days of symptoms. Nearly 77.1% of the operated cases were macula off, whereas 22.85% were macula on. Thirty-six of the eyes (51.4%) had complex RRD with a combination of PVR (34.2%). Sixty-three of the eyes (51.4%) underwent standard 23G pars plana vitrectomy, while the combined surgery with a scleral buckle was performed on 9 eyes (12.8%). Five patients underwent pneumatic retinopexy and two patients had primary scleral buckles. Combined phacoemulsification with vitrectomy in selected cases was performed on 13 eyes (18.5%). Different tamponading agents were used 35 eyes (50%) silicon oil, 17 eyes (24%) C3F8, and 18 eyes (25%) SF6. The primary reattachment rate after one operation was 77.1% (54 eyes). The final reattachment rate following a second or third procedure was 95.7%. The mean postoperative visual acuity was 6/18 (range: 6/6 to hand motions). Thirty percent of the cohort of patients had a visual acuity of 6/12 or better. Sixteen out of the 70 eyes redetached (22.8%) and 10 of those eyes (62.5%) were classified as "complex" preoperatively which is thought to be a significant risk factor for failure. CONCLUSION: Our audit overall met international success rates despite the presence of some complex scenarios which required multiple surgical interventions. The primary use of gas or silicon oil did not influence reattachment rates but had a statistical significance when it came to final visual outcomes.

Long-Term Macular Vascular Changes after Primary Rhegmatogenous Retinal Detachment Surgery Resolved with Different Tamponade or Different Surgical Techniques.

Background: The aim of this study was to assess long-term macular vascular changes and their correlation with functional recovery in patients successfully treated for Macula-ON and Macula-OFF rhegmatogenous retinal detachment (RRD). Methods: This retrospective observational study included 82 eyes of 82 patients who received primary successful retinal detachment surgery, 33 Macula-ON and 49 Macula-OFF. Superficial and deep capillary plexuses (SCP and DCP) were evaluated by optical coherence tomography angiography (OCTA), and were correlated with visual acuity (VA), surgical technique and tamponade at 12 months after surgery. The fellow eyes were used as controls. Results: At 12-month follow-up, there was a significant decrease in the vessel density (VD) in the SCP in the operated eyes compared to control eyes (p < 0.05) in both the Macula-ON and Macula-OFF groups. Vessel length density (VLD) decrease in SCP was more extended in the Macula-OFF group. No difference in the DCP perfusion parameters was found, compared to controls. Subgroup analysis dependent on the type of surgery or tamponade showed no significant differences of VD and VLD. An inverse correlation was found between the SCP VD and the duration of silicone oil (SO) tamponade (p = 0.039). A significant correlation was observed between parafoveal SCP VD and final best corrected visual acuity (BCVA) (p = 0.028). The multivariate linear regression analysis showed that only the type of tamponade was significantly correlated with the final BCVA in the Macula-ON group (p = 0.004). Conclusions: Our study described long-term perfusion changes in RRD after surgery, with lower SCP VD and VLD in the operated eyes compared to the fellow ones, not influenced by type of surgery or tamponade. The choice of tamponade and SO removal timing may affect functional outcomes, especially in Macula-ON RRD. In conclusion, such functional and perfusion changes can be considered biomarkers that highlight the relevance of careful management of this sight-threatening disease.

When the savior becomes a demon: Silicon oil synechia-induced glaucoma.

Background: Silicon oil is an important adjunct for achieving internal tamponade in the treatment of retinal detachment. Silicone oil tamponade often leads to narrowing of the angle and development of adhesions between the iris and anterior chamber angle structures, with consequential elevation of the intraocular pressure. The video showcases the management of these challenging scenarios. Purpose: To highlight the management of early synechial closures due to silicon oil tamponade. Synopsis: The video highlights the management of early synechial closure following silicon oil tamponade. Surgical pupilloplasty has been demonstrated to break the peripheral anterior synechias on intraoperative gonioscopy as well as on anterior segment optical coherence tomography (AS-OCT). Performing pupilloplasty in the early phase of development of peripheral anterior synechias (PAS) helps to break the existing synechias and prevent angle closure and sequential deterioration of vision. Highlights: Surgical pupilloplasty helps to relieve the post silicon oil-induced secondary angle closure glaucoma by breaking the peripheral anterior synechias and significantly opening the anterior chamber angles. Online Video Link: https://youtu.be/xe2NGlhPBF4.

Outcomes of combined phacoemulsification/intraocular lens implantation and silicon oil removal.

PURPOSE: To evaluate the outcomes and complications of simultaneous silicon oil removal (SOR) and phacoemulsification and intra ocular lens implantation. METHODS: In this retrospective non-comparative case series, the visual, refractive and anatomical outcomes of patients who underwent combined phacoemulsification/silicone oil removal (5700 centistokes) surgery between 2017 and 2019 in a single center were evaluated. RESULTS: Forty-four eyes of 44 patients (eighteen males) were included. The mean age of the patients was 51.45 ± 11.59 years. The primary pathology was tractional retinal detachment (TRD) secondary to diabetic retinopathy in 36 eyes and rhegmatogenous retinal detachment (RRD) in 8 eyes. The median time period between silicone oil tamponade and removal was 9 months. There was no statistically significant difference between best corrected visual acuity (-0.14 ± 0.69 LogMAR, p= 0.19) and intraocular pressure (p= 0.26) before and after the surgery. Mean post-operative spherical equivalent (SE) at last visit was 0.36 ± 1.64 which was different from the target refraction (- 0.5D). After cataract/SOR surgery, one eye (2.3%) developed retinal re-detachment in RRD patient. Vitreous hemorrhage occurred in nine eyes (20.5%) which all had TRD as the primary pathology. CONCLUSION: Combined phacoemulsification, silicone oil and IOL implantation removal surgery seems to be a safe and useful procedure with high success rate and acceptable visual, refractive and anatomical outcomes.

[Reasons and risk factors for recurrent retinal detachment after removal of silicon oil in various vitreoretinal diseases]. / Ursachen und Risikofaktoren für eine erneute Netzhautablösung nach Silikonölentfernung bei verschiedenen vitreoretinalen Grunderkrankungen.

BACKGROUND: Pars plana vitrectomy (ppV) combined with silicone oil tamponade is a standard technique in the treatment of complicated retinal detachment. There are still recurrent cases of retinal detachment after silicone oil removal or redetachment with in situ oil tamponade. OBJECTIVE: The aim was to identify possible risk factors for retinal redetachment and to use the knowledge for optimizing treatment. METHODS: Analysis of data from patients who were treated with ppV and silicone oil tamponade in the University Department of Ophthalmology in Marburg during 2010-2015 and who had a retinal redetachment during this period. The results were divided into two groups, redetachment with oil in situ and redetachment after oil removal. RESULTS: A total of 43 cases (15.6%) had a redetachment, which included 22/43 cases (50%) with a redetachment after oil removal and 21/43 cases (50%) with redetachment with oil in situ. The cause for the renewed detachment was given as proliferative vitreoretinopathy (PVR) in 90.6% (39/43) of the cases, new foramina in 20.9% (9/43) and persisting foramina in 25.5% (11/43). CONCLUSION: Vitreoretinal scar formation (PVR reaction) was the main risk factor for renewed retinal detachment. Persisting foramina were also named as a frequent cause. Recurrent retinal detachment represents a significant challenge for vitreoretinal surgeons and for the patients considering the economic and emotional burden due to multiple interventions.

Characterizing Oligomeric Hydroxyl Silicon Oils by MALDI-TOF MS With the Pyridine-Modified Matrix.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) is a powerful technique for analysis of various polymers, but it is still very difficult to characterize silicone oil due to its poor ionization efficiency. In this work, oligomeric hydroxyl silicone oils were successfully characterized by MALDI-TOF, by using pyridine-modified 2,5-dihydroxylbenzoic acid (DHB) as the matrix. Furthermore, the mixed crystal of DHB and hydroxyl silicone oil was analyzed by scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS), and the analytical results verified that modification with pyridine could remarkably improve the solubility of hydroxyl silicone oil in DHB, leading to the enhancement of its ionization efficiency in MALDI. The analysis of the MS spectra of a series of hydroxyl silicone oils indicated that they tended to be ionized by the attachment with Na+, and the average molecular weight and the degree of polymerization were measured for several oligomeric hydroxyl silicon oils.

Rhegmatogenous retinal detachment in Coats' disease: a case report.

BACKGROUND: Coats' disease was originally defined as a unilateral idiopathic exudative retinopathy in young males, characterized by abnormal retinal vascular telangiectasia with intraretinal and subretinal lipid exudation. The retinal detachment is usually exudative. Herein, we describe a case of rhegmatogenous retinal detachment with detectable retinal break in a patient with Coats' disease. CASE PRESENTATION: A 15-year-old Indo-Aryan male patient presented with sudden painless diminution of vision in his right eye of 4 days duration. Upon examination, the anterior segment in both eyes and left fundus was within normal limits. Dilated fundus evaluation of the right eye revealed telangiectasia of the retinal vessels, with subretinal exudation in superotemporal and superonasal quadrants and presence of subretinal fluid in the superotemporal area extending into fovea. There was also presence of single flap horseshoe tear in the superotemporal quadrant at around the 10 o'clock position in the equatorial region, with no secondary changes. The retina was reattached with encircling band buckle combined with vitrectomy and silicon oil tamponade. Seven months post vitrectomy, lenticular opacification developed, for which he underwent silicon oil removal, along with lens aspiration and implantation of foldable intraocular lens. Over the period of 1 year, his best corrected visual acuity improved from 6/60 to 6/18 in the affected eye at the last follow-up visit. The recovery was uneventful following the subsequent surgery. CONCLUSION: Coats' disease has a remarkable diversity in clinical presentation and morphology. The disease can also present with an underlying break, which may not be attributed to any iatrogenic modality. The treatment modalities in coats' disease should be tailored individually due to the low incidence of the disease and the great variation in severity upon presentation. Prompt management restores the best possible anatomical outcome and maintains good vision.

Solution Crystallization of Polycarbonate Surfaces for Hydrophobic State: Water Droplet Dynamics and Life Cycle Assessment towards Self-Cleaning Applications.

Polycarbonate sheets are optically transparent and have the potential to be used as one of the cover materials for PV applications. Solution treatment of polycarbonate surfaces enables to create surface texture topology giving rise to a hydrophobic state, which is favorable for self-cleaning applications. In the present study, hydrophobization of polycarbonate surface is investigated via crystallization of surface by a one-step process. The influence of texture topology, which is created via crystallization, on water droplet mobility and optical transmittance is examined. Findings revealed that solution treatment, using acetone, results in crystallized polycarbonate surfaces with a hydrophobic state. Depending on the treatment duration, the texture characteristics of crystallized surface change while influencing the water contact angle hysteresis. This in turn affects the droplet mobility over the inclined crystallized surface and alters the UV visible transmittance. Moreover, the droplet mobility improves and dust mitigation rates from the treated surface increase as the solution treatment duration are reduced to 2 min. Oil impregnated samples result in improved UV visible transmittance; however, droplet motion changes from rolling to sliding over the surface. A sliding water droplet enables the removal of the dust particles from the oil-impregnated sample surface.

Sliding Water Droplet on Oil Impregnated Surface and Dust Particle Mitigation.

Self-cleaning of surfaces becomes challenging for energy harvesting devices because of the requirements of high optical transmittance of device surfaces. Surface texturing towards hydrophobizing can improve the self-cleaning ability of surfaces, yet lowers the optical transmittance. Introducing optical matching fluid, such as silicon oil, over the hydrophobized surface improves the optical transmittance. However, self-cleaning ability, such as dust mitigation, of the oil-impregnated hydrophobic surfaces needs to be investigated. Hence, solution crystallization of the polycarbonate surface towards creating hydrophobic texture is considered and silicon oil impregnation of the crystallized surface is explored for improved optical transmittance and self-cleaning ability. The condition for silicon oil spreading over the solution treated surface is assessed and silicon oil and water infusions on the dust particles are evaluated. The movement of the water droplet over the silicon oil-impregnated sample is examined utilizing the high-speed facility and the tracker program. The effect of oil film thickness and the tilting angle of the surface on the sliding droplet velocity is estimated for two droplet volumes. The mechanism for the dust particle mitigation from the oil film surface by the sliding water droplet is analyzed. The findings reveal that silicon oil impregnation of the crystallized sample surface improves the optical transmittance significantly. The sliding velocity of the water droplet over the thick film (~700 µm) remains higher than that of the small thickness oil film (~50 µm), which is attributed to the large interfacial resistance created between the moving droplet and the oil on the crystallized surface. The environmental dust particles can be mitigated from the oil film surface by the sliding water droplet. The droplet fluid infusion over the dust particle enables to reorient the particle inside the droplet fluid. As the dust particle settles at the trailing edge of the droplet, the sliding velocity decays on the oil-impregnated sample.

Comparison Between Pars Plana Vitrectomy with and without Encircling Band in the Treatment of Pediatric Traumatic Rhegmatogenous Retinal Detachment.

BACKGROUND AND OBJECTIVES: To compare anatomical and visual results of pars plana vitrectomy (PPV) with or without additional encircling band in the management of pediatric traumatic rhegmatogenous retinal detachment (RD) in a tertiary referral center. METHODS: A retrospective review of children diagnosed with traumatic rhegmatogenous retinal detachment treated by pars plana vitrectomy with or without encircling band. RESULTS: One hundred thirty-nine eyes of 139 children diagnosed with traumatic rhegmatogenous retinal detachment. Surgeries were performed between May 2011 and November 2016. Patients were followed up for at least 18 months after last intervention. The included eyes were categorized into two groups. Group A (vitrectomy with additional encircling band) included 72 eyes of 72 children; 58 boys and 14 girls. Group B (vitrectomy without encircling band) included 67 eyes of 67 children; 58 boys and 9 girls. In group A, the mean age was 9.21±3.24. Attached retina was achieved in 61% (44 out of 72 eyes), of which 34 eyes remained attached after silicon oil removal, and 10 eyes remained attached under silicon oil tamponade. Recurrent RD under oil was present in 28 eyes (38.9%). In group B, the mean age was 11.06±3.64. Attached retina was present in 61.2% (41 out of 67 eyes), of which 30 eyes remained attached after oil removal, and 11 eyes remained attached under silicon oil tamponade. Recurrent RD was present in 26 eyes (38.8%). In group A, the final visual acuity (VA) ranged from NLP to 0.5; 58.7% of patients achieved VA more than counting fingers at 1 meter, and 34.6% of patients achieved VA of 0.05 or more. In group B, the final postoperative VA ranged from NLP to 0.9; 16% of patients achieved VA from counting fingers at 1 meter to 0.05, and 29.2% achieved VA of 0.05 or more. CONCLUSION: Although no statistically significant difference between the two groups (combined vitrectomy and encircling band versus vitrectomy alone in pediatric traumatic retinal detachment), it is wise to consider adding encircling band in severe trauma cases.