The Investigation of Mixed Ferrofluids Containing Iron Oxide nanoparticles and Microspheres

The aim of the present work is the synthesis and characterization of iron oxide (Fe3O4) nanoparticles. These nanoparticles are coated with oleic acid and polyvinyl butyral and mixed with microspheres and further developed ferrofluids with silicon oil. Studies of the performance of the nanoparticles in these ferrofluids with and without coating agents were carried out. The nanoparticles were synthesized using the chemical co-precipitation technique and coated with oleic acid and polyvinyl butyral, and it further mixed with microsphere ferrofluids and developed using silicon oil. The prepared Fe3O4 nanoparticles and their coated forms of oleic acid and polyvinyl butyral were mixed with microspheres; furthermore, ferrofluids were developed with silicon oil. All forms of these ferrofluids are characterized for morphology and phase purity (SEM, XRD, and FTIR). The iron oxide (Fe3O4) nanoparticles have shown different magnetic properties, differentiating macroscopic iron oxide in suspended particles. The ratio of surface to volume increases along with the decrease in atomic size, essential for assessing the surface morphological properties. The magneto-rheological (MR) fluids were determined, and shear stress of Expancel microsphere mixed iron oxide nanoparticle with and without them was found almost equal. However, the ferrofluid with PVB coated nanoparticles and microspheres emerged as a stable rheological ferrofluid, sustaining high shear stress and low viscosity with increasing shear rate. Also, shear rates up to 650 s−1 have been observed, showing very high shear stress withstanding capacity. The stability and performance of the magnetic colloidal ferrofluids depend on the thermal contribution and the balance between attractive/repulsive interactions.

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.

Outcomes of 27 gauge pars plana vitrectomy for a variety of posterior segment diseases

Objective: To report our experience with 27 gauge (27G) pars plana vitrectomy (PPV) system for a variety of simple to complex posterior segment disorders Methods: Single center, Retrospective, Cohort study. Data of 665 eyes of 574 patients that underwent 27G PPV for a variety of indications from July 2015 to June 2019 at a tertiary care hospital was analyzed. Results: Common surgical indications included; Diabetic tractional retinal detachment (196, 29.5%), vitreous haemorrhage (191, 28.7%), full thickness macular hole (80, 12%), epiretinal membrane (66, 9.9%), endophthalmitis (26, 3.9%), tractional diabetic macular edema (14, 2.1%), ectopia lentis (11, 1.7%), dropped lens matter (13, 2%) and others (68, 10.2%). Mean operating time was 62 ± 37 minutes. With the exception of 2 cases where 20G fragmatome was utilized, no case required conversion to 20 gauge system while a 25G trocar was used for the silicon oil injection. Per-operative complications included; iatrogenic retinal tear (2 eyes, 0.3%) and supra choroidal silicon oil migration (1 eye, 0.15%). Post-operative complications were raised IOP (7 eyes, 1%), endophthalmitis (1 eye, 0.15%), hemorrhagic occlusive retinal vasculitis (1 eye, 0.15%) and retinal detachment (2 eyes, 0.3%). Mean Visual Acuity improved from 1.62 ± 0.68 logarithm of minimum angle of resolution (logMAR) to 0.4 ± 0.38 logMAR (P <0.001). Conclusion: With 3 months follow up time, 27 G PPV has proved to be a safe and effective system for both simpler and complex retinal pathologies requiring significant surgical manipulation. Continuous...

The Common Indications of Pars plana vitrectomy (PPV) for posterior Segment Ocular diseases in patients from a Private Retina Clinic

Purpose: To evaluate common indications and anatomical outcomes of PPV for posterior segment ocular diseases in patients presenting at private retina clinic in Lahore Study design: Cross sectional survey Methods and materials: Over the period of three years, from 1st April 2017 to 3oth April 2020, all patients fulfilling inclusion criterion, were included in study after approval from hospital ethical committee. After taking history and detailed ocular examination, diagnosis was confirmed by B scan or OCT, Hepatitis B & C screening done. The patient age, gender, laterality of eye, lens status, macular status, type of retinal pathology, type of anesthesia, procedure done and type of vitreous tamponade if used were noted. All procedures were performed by a single surgical team and patients were followed for six months for anatomical success or any complication. Data was analyzed by SPSS 25. Results: Out of 266 total patients, 168 (63.2%) were males and 98 (36.8%) were females. Right eye was involved in 125 (47%) and left in 141 (53%). Age range was from 2 years to 83years, mean age for males was 47.30, for females 48.07 years, median age was 50 years, mean age for GA was 30.62 years and 51.71 for LA patients. The highest incidences of posterior segment ocular problems were observed in patients with age range 51 to 60 years. The commonest indication for posterior segment surgery were RRD seen in 107 (40.23%), ROSO in 51 (19.17%) and vitreous hemorrhage 33 (12.41%). Endophthalmitis was indication in 20 (7.52%), dropped nucleus in 11 (4.13%), Macular hole in 7 (2.63%) and ERM in 3 (1.13%). Asteroid hyalosis, intraocular IOFB and diagnostic vitrectomy were least common indication, each seen in 1 (0.5%) patient. Silicon oil was most commonly used Endo tamponade used in 138 (51.88%) patients. All patients were followed for 6 months with vision and retinal status. All patients who underwent pars plana vitrectomy surgery were stable with anatomical success rate till 6 months postoperatively except 10 (3.76%) who required re do operation for retinal detachment or some other complications. Conclusion: Current practice in ophthalmology shows increased frequencies of internal approach (PPV) for vitreoretinal diseases rather external approach (SB). Silicon oil was most common internal tamponade used. Diabetic retinopathy was important cause of vitreous hemorrhage and TRD. Patients should be educated regarding regular fundoscopy and good systemic control of diabetes. Higher incidence of retinal detachment among all age groups needs awareness and education about its warning ocular symptoms. Key words: PPV (Pars plana vitrectomy), RRD (Rhegmatogenous retinal detachment), SB (Scleral buckling), TRD (Tractional retinal detachment), ROSO (removal of silicon oil), GA (general anesthesia), LA (local anesthesia)

Methods of correction of aphakia in silicone tamponade of the vitreous cavity

The purpose of this study is to conduct a comparative analysis of the correction of aphakia by various models of intraocular lenses using silicon oil tamponade (SO) of the vitreous cavity. Materials and methods. The studies were conducted on 16 eyes of patients aged from 56 to 75 years (65.5±12 years) with aphakia and pathology of the vitreal cavity. The duration of the silicone tamponade was 2-3 months. Depending on the use of the type of IOL, all patients were divided into 2 groups. Results. When using an anterior chamber intraocular lens (IOL), the presence of ophthalmic hypertension was revealed in 75% of cases, which is 2.02 times higher than when using transcleral IOL fixation. In 37.5% of cases, the SO output to the anterior chamber is determined, in contrast to the group where IOL hemming was used. A higher percentage of SO migration to the anterior chamber of the eye in group 2 patients is due to a violation of the anatomy of the anterior chamber barrier and the vitreal cavity. Conclusion. Thus, in patients who underwent transcleral IOL fixation, visual acuity is 2.1 times higher than in patients who were implanted with an anterior chamber IOL. Transcleral fixation of the IOL can form the necessary barrier between the anterior and posterior chambers of the eye, and is also the closest IOL position to the physiological one. Key words: intraocular lens, silicone oil, transcleral fixation.

The analysis of the results of surgical treatment of macular holes of varying degrees of complexity

Purpose. To provide an analysis of the results of surgical treatment of macular holes, reflecting our own experience of vitreoretinal operations for this pathology of the macular interface. Material and methods. The work was carried out in a private ophthalmological clinic "EyeDoctor" in Almaty, Kazakhstan. The patients were divided into 3 groups, depending on the stage of macular holes and concomitant eye diseases. Results. 1. The macular hole 2-3 stage it is enough to carry out vitrectomy with careful removal of the ILM and PRP technology (the defect is up to 400 microns). 2. The macular hole 4 stage – removal the ILM with PRP technology with obligatory tamponade with silicon oil. Conclusion. To predict the results, it is necessary to take into account the stage of macular hole, its morphological and functional parameters, the duration of the process and the presence of concomitant ocular pathology. Key words: macular hole, J.D. Gass classification, vitrectomy, PRP method.

The Discovery of Floating Boats on the Oscillating Levitated Liquid Layer

When air bubbles are injected into a still bath with liquid, it’s known that they will rise to the top surface because of their small mass. However, oscillations, which can provide a dynamical stabilizing effect, can make air bubbles sink when created below a certain depth that changes along with the forcing amplitude. Three experiments are needed to show the defy-gravity behavior caused by vibration on liquid. Using silicon oil, a syringe, a needle, and a vertically oscillating shaker with amplitude, an air layer formed by sinking bubbles, which defy the well-known Archimedes’ principle, is being trapped under the levitating liquid layer acts as a spring-mass. With the further experiment using two light foam boats, it was observed that an upside-down buoyant force was acting on the liquid provided by vibration, supporting the boats to flow on both interfaces of the liquid layer. A symmetric Archimedes’ principle is discovered to be reflected on the lower interface created by the dynamic stabilization as well. This discovery about the effect vibration can have on liquid, and alternately the forces acting on the object floating on this liquid brings lots of future development to light and is new progress in the area of fluid mechanics.