Vitreoretinal Surgery in the Treatment of Dislocations of Intraocular Lens and Nucleus-Lens Particules into the Vitreous Cavity

Drops of lens nucleus/cortex particles into the vitreous cavity or dislocations of intraocular lenses (IOLs) are one of the serious complications of cataract surgery with an increasing relative frequency with the increase in the number of cataract surgeries. In addition, spontaneous and traumatic dislocations are other common case groups that should be treated. In this article, the vitreous dislocations of nucleus/cortex residues or IOL dislocations are discussed with different vitreoretinal surgical techniques.

Human Umbilical Cord-Mesenchymal Stem Cells Survive and Migrate within the Vitreous Cavity and Ameliorate Retinal Damage in a Novel Rat Model of Chronic Glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide, and pathologically elevated intraocular pressure (IOP) is the major risk factor. Neuroprotection is one of the potential therapies for glaucomatous retinal damage. Intravitreal mesenchymal stem cell (MSC) transplantation provides a viable therapeutic option, and human umbilical cord- (hUC-) MSCs are attractive candidates for cell-based neuroprotection. Here, we investigated the ability of transplanted hUC-MSCs to survive and migrate within the vitreous cavity and their neuroprotective effects on chronic glaucomatous retina. For this, we developed a chronic ocular hypertension (COH) rat model through the intracameral injection of allogeneic Tenon’s fibroblasts. Green fluorescent protein-transduced hUC-MSCs were then injected into the vitreous cavity one week after COH induction. Results showed that a moderate IOP elevation lasted for two months. Transplanted hUC-MSCs migrated toward the area of damaged retina, but did not penetrate into the retina. The hUC-MSCs survived for at least eight weeks in the vitreous cavity. Moreover, the hUC-MSCs were efficient at decreasing the loss of retinal ganglion cells; retinal damage was attenuated through the inhibition of apoptosis. In this study, we have developed a novel COH rat model and demonstrated the prolonged neuroprotective potential of intravitreal hUC-MSCs in chronic glaucoma.

4D Investigation of Vortex Fluid Motion Inside the Eyeball

The eye is a complex system of boundaries and fluids with different viscosities within the boundaries. At present, there are no experimental possibilities to thoroughly observe the dynamic 4D processes after one or another method of eye treatment is applied. The complexity of cumulative, i.e., focusing, and dissipative, i.e., scattering, convective and diffusion 4D fluxes of fluids in the eye requires 4D analytical and numerical models of fluid transfer in the human eyeball to be developed. The purpose of the study was to develop and then verify a numerical model of 4D cumulative-dissipative processes of fluid transfer in the eyeball. The study was the first to numerically evaluate the values of the characteristic time of the drug substance in the vitreous cavity until it is completely washed out, depending on the injection site; to visualize the paths of the vortex motion of the drug in the vitreous cavity; to determine the main parameters of the 4D fluid flows of the medicinal substance in the vitreous cavity, depending on the presence or absence of vitreous detachment from the wall of the posterior chamber of the eye. The results obtained are verified by the experimental data available to doctors. In the eye, as a partially open cumulative-dissipative system, Euler regions with high rates of cumulative flows and regions with low speeds or stagnant Lagrange flow zones are defined

Evaluation of the Ophthalmotoxic Effect of Quantum Dots and Bioconjugates Based on Them in Terms of the Prospects for the Treatment of Resistant Endophthalmitis. Experimental Research (Stage 1)

Endophthalmitis remains one of the most formidable complications of surgery in ophthalmology, leading to significant functional and anatomical changes. The “gold” standard of treatment for this pathology is the installation of intravenous injections of antibacterial drugs, but taking into account the number and type of pathogens, the growth of antibiotic resistance, the search for alternative methods of treatment of endophthalmitis remains relevant. Colloidal quantum dots, which are nanoscale semiconductor crystals with simulated optical and electronic properties due to changes in their volume, composition, and surface connections, are of interest for research in this direction. This article presents the process of synthesis of CT and bioconjugates based on them in order to assess ophthalmotoxicity with the prospect of further use in the treatment of endophthalmitis. The study was divided into 4 stages, starting with the determination of the required technical specification in order to select the appropriate type of quantum dots taking into account the physical and chemical characteristics (Stage 1), the synthesis of quantum dots (Stage 2), the preparation and titration of a solution of quantum dots of various concentrations for implantation in the vitreous cavity (Stage 3). The final stage was to evaluate the toxic effect of the quantum dot solution in its pure form, as well as in combination with antibiotics (ceftazidime and vancomycin) when administered intravitreally on an animal model. As a result of the study, quantum dots were synthesized and a solution based on them was obtained for introduction into the vitreous cavity. Based on the testing of the animal model (rabbits), a safe dose of the solution was determined, as well as the possibility of its use in combination with antibiotics.

Malignant Glaucoma in a Pseudophakic Eye with Slack Lens Zonules

Purpose: To report a case of malignant glaucoma after glaucoma surgery in a pseudophakic eye with slack lens zonules.Case summary: An 83-year-old man presented with high intraocular pressure of the left eye. He underwent cataract surgery in the left eye ten years ago. He was diagnosed with glaucoma two years ago and had used anti-glaucoma medications. The initial examination of the left eye revealed intraocular pressure of 24 mmHg and zonular dehiscence. We performed Ahmed valve implant surgery because medical treatment failed to lower the intraocular pressure. The anterior chamber angle was nearly closed. After the surgery, over-filtration of aqueous fluid was observed. Injecting the balanced salt solution into the anterior chamber demonstrated misdirected flow of aqueous fluid into the vitreous cavity behind the unstable intraocular lens. The eye was diagnosed with malignant glaucoma; therefore, pars plana vitrectomy was performed. After the vitrectomy, the anterior chamber was not deep; therefore, we repositioned the tip of Ahmed valve implant from the anterior chamber to the vitreous cavity. Subsequently, the anterior chamber became deep and intraocular pressure normalized. The patient remained stable two months after the vitrectomy.Conclusions: Malignant glaucoma can occur in pseudophakic eyes with slack lens zonules after glaucoma surgery, due to misdirection of aqueous fluid. This case suggests that the tip of Ahmed valve implant should be located in the vitreous cavity after vitrectomy, to prevent misdirected flow of aqueous fluid.

Vitreous Noise on Optical Coherence Tomography as an Early Finding of Brolucizumab-Related Intraocular Inflammation

We describe a case of brolucizumab-related intraocular inflammation (IOI) detected using vitreous haze on optical coherence tomography (OCT) at an early stage before the patient was aware of any symptom. A 69-year-old female presented with decreased right vision. The patient was diagnosed with pachychoroidal neovasculopathy and started intravitreal aflibercept (IVA) with a 3+ treat-and-extend strategy (TAE). Although the serous retinal detachment (SRD) disappeared after IVA treatment, the patient was managed with treatment every 4 weeks without extending the treatment interval To shorten the treatment interval, intravitreal brolucizumab (IVBr) was started 44 weeks after starting IVA treatment. After initiating IVBr treatment, the SRD completely disappeared. However, 16 weeks after starting IVBr, OCT showed noise in the vitreous cavity, which had not been seen before, and infrared images showed a black smoke-like shadow over the macula. Despite these findings, the patient had no subjective symptoms, and so IVBr was re-administered with an 8-week TAE interval. Five days after IVBr treatment, vitreous inflammatory cells were observed, and the noise in the vitreous cavity and the smoke-like shadow in the infrared image were further enhanced. We diagnosed the patient with brolucizumab-related IOI, and anti-inflammatory treatment was initiated. After extensive treatment, the vitreous opacity gradually disappeared, and the vitreous noise on OCT and the black smoke-like shadow on infrared images disappeared. IOI may have already been present 16 weeks after starting IVBr treatment, when we judged that there was no inflammation and IVBr was re-administered. When following patients receiving IVBr, IOI may be detected by OCT at an earlier stage by evaluating vitreous haze.

SIGNIFICANCE OF ULTRASONOGRAPHY IN EVALUATION OF VITREORETINAL PATHOLOGY

INTRODUCTION:Vitreoretinal pathologies include vitreal haemmorhage and vitreal detachment, retinal detachment, retinoblastoma, diabetic retinopathy, leukocoria, trauma over eye. The eye being an external sense organ lends itself to an easy and rapid examination of anterior segment but structure posterior to the papillary plane i.e lens, vitreous cavity and humor, retina, choroid in an opaque media could not be evaluated by just fundus examination. OBJECTIVES OF RESEARCH: Demographic prole of patient with vitreoretinal pathologies. Diagnose the patient with vitreoretinal pathologies by ultrasonography. Detect and characterize the vitreoretinal pathologies by ultrasonography, clinical ndings and post management conrmatory ndings to establish the diagnostic accuracy of ultrasonography in vitreoretinal pathologies. MATERIALAND METHOD: Study design:Institution based prospective, descriptive study Study setting: USG section at Dept. of Radiodiagnosis, Medical College, Kolkata Place of study: Dept. of Radiodiagnosis, Medical College, Kolkata Period of study:January 2018 to august 2019 Study population:Referred patient from regional institute of opthalmology Sample size: 50 patients. RESULT AND ANALYSIS: We showed that 29(48.3%0 patients had vitreous haemorrhage. 19(31.7%) patients had retinal detachment. 10(16.7%) patients had posterior vitreous detachment. 7(11.7%) patients had endophthalmitis. 9(15.0%) patients had retinoblastoma. 1(1.7%) patients had PHPV. 1(1.7%) patients had asteroid hyalosis. 1(1.7%) patients had retinoschisis. 5(8.3%) patients had normal. SUMMARYAND CONCLUSION: From, the present study it was noted that Ultrasonography is very efcient tool in diagnosing various ocular abnormalities. Ultrasonography can categorize the lesions in the posterior chamber well, depending on the echotexture and anatomy. Even the exact location of the lesion and surrounding structures can be well made out. Ultrasonography can detect structural changes that were missed or could not be detected by clinical examination especially with opaque media as well. Ultrasonography is proved to be very useful diagnostic tool in detection and evaluation of vitreo-retinal pathologies in patients with opacities in the vitreous cavity.

Anti-Vascular Endothelial Growth Factor Therapy as an Adjunct to Diabetic Vitrectomy

Introduction: The purpose of this work is to study the efficacy of the preoperative intravitreal administration of bevacizumab as an adjunct to vitrectomy in patients with Proliferative Diabetic Retinopathy (PDR). Methods: This retrospective comparative study was performed on 118 eyes (118 patients) with proliferative diabetic retinopathy (PDR), which underwent vitrectomy surgery at the Department of Diabetic Eye Disease at Zarifa Aliyeva National Ophthalmology Centre (Baku, Azerbaijan) in 2015-2019. The main group (the bevacizumab group) included 48 eyes with PDR that received intravitreal administration of bevacizumab (Avastin; Genentech Inc., USA) within one week before vitrectomy; the control group included 70 eyes that did not receive a bevacizumab injection for at least 3 months before the vitrectomy. The minimum follow-up was 12 months. Results: In both groups, complete retinal attachment after primary vitrectomy was achieved in all eyes (100%). Clinically significant intraoperative haemorrhage was observed in the preoperative bevacizumab injection group in 31.2% and the control group- 51.4%, p = 0.030. The preoperative bevacizumab injection reduced the risk of clinically significant haemorrhage by 2.3 times and the need for endodiathermy by 2.7 times (p = 0.031 and p = 0.024, respectively). Early vitreous cavity haemorrhage was observed in 15.0% in the bevacizumab group and in 35.5% in the control group (p = 0.038). The preoperative injection of bevacizumab before vitrectomy reduced the risk of vitreous cavity haemorrhage in the early postoperative period by 3.0 times (p = 0.036). Conclusion: The preoperative use of bevacizumab as an adjunct to diabetic vitrectomy can help reduce the incidence of intraoperative and early postoperative vitreous cavity haemorrhage, which leads to better functional results in the early postoperative period. Over the long-term follow-up period, the effect of the preoperative bevacizumab injections decreases.

Intraocular Temperature at Different Sites in Eye Measured at the Beginning of Vitreous Surgery

The temperature of the vitreous has been reported to vary during cataract and vitreous surgery. We measured intraocular temperature at four intraocular sites; the anterior chamber (AC), just behind the crystalline lens, mid-vitreous, and just anterior to the optic disc (OD) at the beginning of vitrectomy with a thermoprobe in 48 eyes. The temperatures were compared in three groups; eyes that underwent vitrectomy for the first time (Group V, n = 30), eyes that had previous vitrectomy and the vitreous cavity had been filled with balanced salt solution (BSS; Group A, n = 12), and eyes that had previous vitrectomy and the vitreous cavity was filled with silicone oil (Group S, n = 6). There was a gradient in the temperature in all groups, i.e., it was lowest in the AC, and it increased at points closer to the retina. The intraocular temperature was significantly correlated with the type of fluid in the vitreous cavity. The mean intraocular temperatures were not significantly different in Groups V and A, but they were significantly higher in Group S. Clinicians should be aware of the differences in the temperature at the different intraocular sites because the temperatures may affect the physiology of the retina and the recovery process.