Prolonged Release Niosomes For Ocular Delivery of Loteprednol: Ocular Distribution Assessment on Dry Eye Disease Induced Rabbit Model.

Loteprednol etabonate (LE) is a topical corticosteroid for the symptomatic management of ocular conditions, encompassing both allergic and infectious etiologies. Owing to the dynamic and static barriers of the eye, LE exhibits significantly low bioavailability, necessitating an increase in the frequency of drug administration. The objective of this study is to overcome the limitations by developing niosomal systems loaded with LE. Design of Experiments (DoE) approach was used for the development of optimal niosome formulation. The optimal formulation was characterized using DLS, FT-IR, and DSC analysis. In vitro and ex vivo release studies were performed to demonstrate drug release patterns. After that HET-CAM evaluation was conducted to determine safety profile. Then, in vivo studies were carried out to determine therapeutic activity of niosomes. Zeta potential (ZP), particle size, polydispersity index (PI), and encapsulation efficacy (EE) were -33.8 mV, 89.22 nm, 0.192, and 89.6%, respectively. Medicated niosomes had a broad distribution within rabbit eye tissues and was absorbed by the aqueous humor of the bovine eye for up to 6 h after treatment. Cumulative permeated drug in the bovine eye and rabbit eye were recorded 52.45% and 54.8%, respectively. No irritation or hemorrhagic situation was observed according to the results of HET-CAM study. Thus, novel LE-loaded niosomal formulations could be considered as a promising treatment option for the dry-eye-disease (DED) due to enhanced bioavailability and decreased side effects.

Aqueous Humor-Derived MYD88 L265P Mutation Analysis in Vitreoretinal Lymphoma: A Potential Less Invasive Method for Diagnosis and Treatment Response Assessment.

PURPOSE: To investigate whether MYD88 L265P mutation, which is frequently present in vitreoretinal lymphoma, can be detected in aqueous humor, a specimen that can be obtained in a clinic setting, potentially mitigating the need for more invasive vitrectomy procedures, and whether this approach can be used to monitor treatment response. DESIGN: Observational case series. SUBJECTS: Patients who were diagnosed with biopsy-confirmed or clinically diagnosed vitreoretinal lymphoma or biopsy-confirmed vitritis. METHODS: We evaluated aqueous humor-derived (AHD) MYD88 L265P mutation during vitreous biopsy or at the initial presentation in the clinic if vitreous biopsy was not feasible. Demographic or clinical features of patients were retrospectively reviewed. Aqueous humor-derived MYD88 L265P mutation was re-evaluated after patients completed a course of intravitreal methotrexate and rituximab injection therapy. The NM_002468.4: c.794T>C (p.L265P) mutation in the MYD88 gene was evaluated in AHD cellular and cell-free DNA using allele-specific polymerase chain reaction. MAIN OUTCOME MEASURES: Detection of AHD MYD88 L265P mutation at the initial diagnosis and to monitor the treatment response. RESULTS: Aqueous humor from 18 eyes of 14 patients with biopsy-confirmed or clinically diagnosed vitreoretinal lymphoma and 3 eyes of 3 patients with biopsy-confirmed vitritis were evaluated. Aqueous humor-derived MYD88 L265P mutation was detected in cell-based and cell-free DNA from 15 (83%) of 18 eyes with biopsy-confirmed or clinically diagnosed vitreoretinal lymphoma but not identified in any of the 3 eyes with vitritis. The mutation was less readily detectable in cellular DNA (10 of 18) compared with cell-free DNA (15 of 18). Furthermore, aqueous sampling after intravitreal methotrexate and rituximab injection therapy revealed absence of this mutation after complete response in 7 eyes. The mutation was detected in 1 eye that developed recurrence in a posttreatment window of 6 months. After a mean of follow-up of 9 months, there was no clinical evidence of vitreoretinal lymphoma recurrence in the 7 eyes with no detectable AHD MYD88 L265P mutation. CONCLUSIONS: This investigational study suggests that AHD MYD88 L265P can be detected in eyes with lymphoma and may thus serve as a surrogate, less invasive biopsy in the diagnosis and follow-up of vitreoretinal lymphoma, particularly when cell-free DNA is evaluated.

Expression of Long Non-Coding RNA (lncRNA) SNHG5 in Patients with Refractory Diabetic Macular Edema and Its Regulatory Mechanism.

BACKGROUND The aim of this study was to assess use of lncRNAs as biomarkers in serum and aqueous humor of patients with diabetic macular edema (DME). MATERIAL AND METHODS Optical coherence tomography and fundus photography were used to analyze the retinal features of the patients. RT-qPCR was used to analyze the differential expression of lncRNA snhg5 in patients who have idiopathic macular hole (MH), DME, or refractory DME. The relationship between SNHG5 and the clinical characteristics of the patients was analyzed. The effect of SNHG5 on the hyperplasia and apoptosis of human retino-microvascular endothelial cells (HRMECs) and its mechanism were analyzed in vitro. RESULTS Patients with idiopathic MH developed retinal nerve epithelium rupture and retinal fundus thickening, and patients with DME or refractory DME showed significant macular edema with hemorrhaging. The refractory DME patients improved after treatment but still showed significant macular edema and multiple laser scarring. SNHG5 expression was not only low in the atrial fluid and plasma in DME patients, but also lower in the refractory DME group compared to the idiopathic MH patients. SNHG5 expression in the aqueous humor and plasma was negatively correlated with disease duration, body mass index, and levels of fasting blood glucose, glycated hemoglobin, proteinuria, and glycosuria. In the in vitro experiments, SNHG5 expression was significantly downregulated in high glucose-induced HMECs. After SNHG5 overexpression, cell proliferation, angiogenesis, and VEGF-A protein levels were distinctly downregulated. CONCLUSIONS SNHG5 correlates with the development of DME and is a potential target for therapy.

Aqueous Cytokine Expression and Higher Order OCT Biomarkers: Assessment of the Anatomic-Biologic Bridge in the IMAGINE DME Study.

PURPOSE: To identify biomarkers for predicting response to anti-vascular endothelial growth factor (VEGF) therapy in diabetic macular edema (DME) and evaluate any links between cytokine expression and optical coherence tomography (OCT) phenotype. DESIGN: The IMAGINE is a post hoc image analysis and cytokine expression assessment of the Efficacy & Safety Trial of Intravitreal Injections Combined With PRP for CSME Secondary to Diabetes Mellitus (DAVE) randomized clinical trial. METHODS: Subjects were categorized as anatomical responders or nonresponders, and within the responder group as rebounders and non-rebounders based on quantitative, longitudinal OCT criteria. Retinal layer and fluid features were extracted using an OCT machine-learning augmented segmentation platform. Responders were further sub-classified by rapidity of response. Aqueous concentrations of 54 cytokines were measured at multiple timepoints. Expression was compared between responder groups and correlated with OCT imaging biomarkers. RESULTS: Of the 24 eyes studied, 79% were anatomical responders with 38% super responders, 17% early responders, and 25% slow responders. Twenty-one percent were nonresponders. Super responders had increased baseline vascular endothelial growth factor (VEGF) (880.0 pg/mL vs 245.4 pg/mL; P = .012) and decreased monocyte chemotactic protein-1 (MCP-1) (513.3 pg/mL vs 809.5 pg/mL; P = .0.042) concentrations compared with nonresponders. Interleukin-6 (-24.9 pg/mL vs 442.8 pg/mL; P = .032) concentrations increased among nonresponders during therapy. VEGF concentrations correlated with central subfield thickness (r = 0.49; P = .01). Panmacular retinal volume correlated with increased interleuckin-6 (r = 0.47; P = .02) and decreased MCP-1 (r = -0.45; P = .03). Matrix metallopeptidase-1 correlated with subretinal fluid volume (r = 0.50; P = .01). CONCLUSIONS: OCT imaging biomarkers correlated with both intraocular cytokines and responsiveness to anti-VEGF therapy, which indicated a possible link to underlying pathways and their relevance to DME prognosis. Baseline concentrations of VEGF and MCP-1 are associated with anatomic response to anti-VEGF therapy.

Nonclinical Pharmacokinetic and Pharmacodynamic Assessment of Bimatoprost Following a Single Intracameral Injection of Sustained-Release Implants.

Purpose: To assess the pharmacokinetic (PK)/pharmacodynamic (PD) relationship following intracameral Bimatoprost sustained-release (SR) implants (8, 15, 30, and 60 µg) in dogs to determine the optimal investigative dose in humans. Methods: Forty-four male normotensive beagle dogs were assigned to 1 of 8 groups receiving 8-, 15-, 30-, and 60-µg implants (PD assessment [n = 8/group, 4 groups]; PK assessment [n = 3/group, 4 groups]). Intraocular pressure (IOP) in PD animals and aqueous humor/blood concentrations of bimatoprost and its acid in PK animals were assessed. PK/PD correlation analysis was performed using steady-state data. Residual implants were recovered to assess polymer degradation. Results: Dose-dependent IOP lowering was observed for all dose groups for at least 3 months postdose. Blood concentrations of bimatoprost and bimatoprost acid were below the limit of quantification (<0.25 ng/mL), whereas dose-dependent concentration-time profiles were observed in the aqueous humor. At steady state, observed and predicted correlation between aqueous humor drug concentration and IOP lowering was similar and translatable to findings in humans following topical bimatoprost eyedrop administration. Implants at all doses were well tolerated and polymer degradation was apparent. Conclusions: Dose-dependent IOP lowering with Bimatoprost SR was maintained for at least 3 months in dogs, and the implants were well tolerated. The established PK/PD relationship appears to translate to humans. Doses between 8 and 15 µg appear to provide the best benefit/risk profile for clinical development of the implants. Translational Relevance: The close PK/PD relationship between dog and human helps inform which bimatoprost dose should be investigated in clinical studies.

Comparative assessment of intraocular inflammation following standard or heavy silicone oil tamponade: a prospective study.

PURPOSE: To evaluate the inflammation associated with the use of standard silicone oil (polydimethylsiloxane; PDMS) and heavy silicone oil (HSO) Densiron-68™ in patients undergoing vitrectomy for retinal detachment. MATERIALS AND METHODS: A prospective study was performed involving 35 patients scheduled to undergo vitrectomy for retinal detachment. Patients received PDMS or Densiron-68™ HSO according to superior or inferior retinal localization of the tears, respectively. For assessing the inflammation, prostaglandin E2 (PGE2 ) and interleukin-1α (IL-1α) levels were evaluated in the aqueous. RESULTS: Thirty-five eyes of 35 patients completed the study: 20 eyes received HSO, and 15 eyes received PDMS. The mean aqueous PGE2 level was significantly higher in HSO patients than in PDMS patients (869.16 ± 242.83 pg/ml versus 369.38 ± 209.7 pg/ml, respectively; p < 0.0001). The mean aqueous IL-1α level was also significantly higher in HSO patients than in PDMS patients (81.40 ± 36.9 pg/ml versus 40.8 ± 32.5 pg/ml, respectively; p = 0.002). In HSO, a moderate positive correlation between the endotamponade duration and both PGE2 (r = 0.44; p = 0.05) and IL-1α (r = 0.48; p = 0.033) levels was observed. In PDMS, a strong positive correlation between the endotamponade duration and both PGE2 (r = 0.89; p < 0.0001) and IL-1α (r = 0.68; p = 0.006) levels was observed. CONCLUSION: Although both HSO and PDMS yielded favourable success rates in the surgical treatment of complicated retinal detachments, HSO triggered a more severe inflammatory reaction, in a time-dependent manner.

[Endothelins and dopamine levels in tears for assessment of neurovascular disorders in glaucoma]. / Éndoteliny i dofamin v sleznoi zhidkosti v otsenke neirovaskuliarnykh narushenii pri glaukome.

PURPOSE: To estimate the possibility of detection of neurovascular ocular disorders in glaucoma by assessing the content of catecholamines and endothelins in lacrimal fluid. MATERIAL AND METHODS: The study included 47 patients with primary open-angle glaucoma (POAG). Tear eluate was analyzed by high performance liquid chromatography (HPLC) for catecholamines concentrations, and enzyme-linked immunoassay (ELISA) was used for evaluation of endothelins content. RESULTS: Endothelin-1 (ET-1) and big endothelin (bET) content in tears of patients with POAG was higher than in healthy controls. Concentration of dopamine (DA) in tears was lower and concentrations of L-dioxyphenylalanine and dihydroxyphenylacetic acid had a tendency for decrease. Noradrenaline content was equal in patients with POAG and controls. Adrenaline was not detected in any tear samples. CONCLUSION: Multidirectional changes of endothelins and DA levels in tears of patients with POAG was found. The increased concentration of ET-1 and its precursor bET promote vasoconstriction and decrease of aqueous humor outflow. The decrease of DA concentration is typical for neurodegenerative processes. Estimation of DA and endothelins concentrations in tears can enable early detection of neurovascular disorders in glaucoma patients and help evaluate their severity.

Clinical Results and Utility of Herpesviruses Multiplex Polymerase Chain Reaction: Assessment of Aqueous Humor Samples From Patients With Corneal Endotheliitis and High Intraocular Pressure.

PURPOSE: The main purpose of this study was to evaluate herpesvirus infection in patients with corneal endotheliitis and high intraocular pressure (IOP) using multiplex polymerase chain reaction (PCR) in aqueous humor samples. MATERIALS AND METHODS: This was a retrospective, observational study of immunocompetent patients living in South Korea. Eligible subjects had typical corneal endotheliitis with an IOP≥21 mm Hg or required antiglaucoma medication. Multiplex PCR was performed using aqueous humor samples obtained at first visit to detect the DNA of 6 herpesviruses. RESULTS: Forty-two eyes from 42 patients with >6 months' follow-up were analyzed. Of these, 16 were herpesvirus-positive: 3 herpes simplex virus 1, 3 varicella-zoster virus, 9 cytomegalovirus, and 1 Epstein-Barr virus. Eyes with coin-shaped or fine keratic precipitates (kps), high IOP, and a low baseline endothelial cell count were more likely to show a positive result on multiplex PCR. Univariate analysis showed that male sex (P=0.014), a previous history of uveitic glaucoma (P=0.048), and the presence of fine kps (P=0.031) were significantly associated with a positive PCR result. On multivariate analysis, male sex (P=0.010) and a previous history of uveitic glaucoma (P=0.031) showed a significant positive association. CONCLUSIONS: Cytomegalovirus was the most commonly detected herpesvirus in patients with corneal endotheliitis and high IOP. A positive PCR result was seen more frequently in male individuals and patients with fine kps or a history of uveitic glaucoma.

Quantitative Assessment of Aqueous Flare After Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy.

PURPOSE: To assess aqueous flare as a measure of subclinical inflammation after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy. METHODS: In this prospective cross-sectional and longitudinal case series at a tertiary referral center, 173 DMEK eyes of 169 patients and 19 age-matched healthy control eyes were included. Aqueous flare [photon count per millisecond (ph/ms)] was assessed by laser flare photometry at 1 day, 1 week, and 1 month after DMEK in group I (evaluation of postsurgical blood-aqueous barrier recovery; n = 25) and on average 28 (±19) months (range, 3-86 months) after DMEK in group II (evaluation of long-term inflammation; n = 148). RESULTS: In group I, flare levels decreased from 1 day to 1 week [25.1 (±9.1) ph/ms vs. 13.4 (±4.8) ph/ms; P = 0.003] and remained stable up to 1 month after DMEK [12.1 (±3.2) ph/ms; P = 0.387]. However, average flare at 1 month was higher than that in healthy controls (P < 0.001). The long-term flare value after DMEK (group II) was 9.6 (±4.2) ph/ms and was higher in eyes associated with allograft rejection (n = 6) versus those without rejection [16.7 (±7.8) ph/ms vs. 9.3 (±3.8) ph/ms, respectively, P < 0.001]. All eyes associated with rejection had flare values above 10 ph/ms. CONCLUSIONS: Aqueous flare after DMEK quickly decreased within the first postoperative month, indicating fast recovery of the blood-aqueous barrier. Long-term flare levels were higher in eyes associated with rejection, suggesting persistent subclinical inflammation. A flare level above 10 ph/ms may be used as a threshold for identifying eyes associated with or at risk of allograft rejection after DMEK.

Assessment of Aqueous Humor Dynamics in the Rodent by Constant Flow Infusion.

Mice and rats are being increasingly used in glaucoma research and much useful data have been generated from them. One aspect of using these animals for this purpose involves assessment of aqueous humor dynamics. Several techniques have been described in the literature for the determination of one or more of these parameters in rodents, in both living animals and eyes perfused ex vivo. Here, we describe the practical details for a technique for the determination of all principal parameters of aqueous humor dynamics (intraocular pressure (IOP), aqueous humor formation rate (Fin), uveoscleral outflow rate (Fu), aqueous outflow facility (C), and episcleral venous pressure (Pe)) in the living rat and mouse eye, in a single experimental session.

Functional assessment of the aqueous humour distal outflow pathways in bovine eyes using time-of-flight magnetic resonance tomography.

The major part of the aqueous humor leaves the eye through the "conventional outflow pathway", consisting of the trabecular meshwork, Schlemm's canal, collector channels, an intrasceral plexus and the episcleral veins. While the trabecular meshwork is well characterized, little is known about anatomical and functional features of the peripheral outflow tract beyond Schlemm's canal. The emergence of minimally-invasive glaucoma surgery directly targeting the outflow resistance in the trabecular meshwork has elicited growing interest in these structures. We used time-of-flight magnetic resonance imaging in ex vivo bovine eyes to map fluid flow under physiological conditions. We were able to identify the peripheral outflow vessels solely by the signal detected from the fluid flow inside their lumina. A question of clinical relevance is, whether localized opening of the trabecular meshwork leads to only localized or to a 360° increase in intrascleral flow. To address this, a goniotomy ab interno was performed in 3 eyes and the flow signal intensity was quantified sectorially. A significant increase in fluid flow was observed in the sector distal to the goniotomy (p = 0.0005) but not in the other sectors (p = 0.1). As a proof of concept we demonstrated that TOF-MRI based detection of flow in the peripheral aqueous outflow tract is feasible. The functional link observed between trabecular meshwork sectors and their distal outflow tract sectors may be relevant for minimally-invasive glaucoma surgery in humans.

Assessment of biomarkers using multiplex assays in aqueous humor of patients with diabetic retinopathy.

BACKGROUND: With the high prevalence of type 2 diabetes, diabetic retinopathy (DR) has become a leading health problem worldwide. The pathogenesis of DR is complex and several vascular, inflammatory, and neuronal mechanisms are involved. The purpose of this study was to assess the levels of immune and inflammatory biomarkers in the aqueous humor of patients with different severities of DR and to analyze the correlations between Interleukin-6 (IL-6) and these biomarkers, and between IL-6 and the severity of the disease. METHODS: Aqueous humor samples were obtained from 51 non-diabetic patients and 151 diabetic patients. Levels of 45 different cytokines, chemokines, and growth factors were measured using a multiplex bead immunoassay. RESULTS: IL-6, IL-8, Inducible Protein-10 (IP-10), leukemia inhibitory factor (LIF), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF)-A were significantly higher (p < 0.05) in the aqueous humor of the DR patients compared to the non-diabetic patients, while the concentrations of IL-1α, IL-4, IL-9, IL-21, IL-23, IL-27, IL-31, RANTES, interferon-α, growth regulated oncogene (GRO), and tumor necrosis factor (TNF)-α were significantly lower (p < 0.05) in the DR patients. The IL-6 levels increased as the severity of DR increased. In addition, the IL-6 level positively correlated with the IL-8, HGF and LIF levels, while negatively with the IL-31and GRO levels. CONCLUSIONS: These findings suggest that inflammation and immune response may contribute to the pathogenesis of DR, and these biomarkers may potentially be new therapeutic targets for DR.

Gadolinium-enhanced 7.0 T magnetic resonance imaging assessment of the aqueous inflow in rat eyes in vivo.

The goal of this study was to calculate the anterior chamber volume and assess aqueous inflow in rat eyes in vivo, under anesthetic condition. Gadolinium-contrast agent (Gd-DTPA, 234.5 mg/ml) was administered to Sprague-Dawley rat eyes via anterior chamber injection or instillation of 234.5 or 117.25 mg/ml Gd-DTPA in 0.2% azone as eye drops, and changes of Gd signal visualized by 7.0 T magnetic resonance imaging (MRI). The safety of local application of Gd-DTPA and azone were performed after MRI scanning. The anterior chamber injection of Gd-DTPA (234.5 mg/ml) group was used for anterior chamber volume and aqueous inflow calculating. Serial changes in Gd-DTPA relative concentration in the anterior chamber was determined based on the initial Gd signal gray values and the initial relative concentration of Gd-DTPA after anterior chamber Gd-DTPA injection. The mean aqueous inflow in rat eyes in vivo was assessed based on changes in Gd-DTPA relative concentration and the anterior chamber volume. Eye drops of Gd-DTPA (234.5 mg/ml) in 0.2% azone readily allowed safe assessment of the aqueous inflow by 7.0 T MRI. Under anesthetic condition in vivo, the mean anterior chamber volume (ACV) in rats was 8493.6 ± 657.4 µm3, no differences were observed in the aqueous inflow measured by topical instillation of 234.5 mg/ml Gd-DTPA in 0.2% azone (0.182 ± 0.011 µl/min) between that measured by anterior chamber injection (0.165 ± 0.041 µl/min, P > 0.05), Timolol reduced aqueous inflow to 0.124 ± 0.020 µl/min (P < 0.05). Our results indicated that Gd-enhanced 7.0 T MRI allows evaluation of the Gd signal variation and anterior chamber volume in rats in vivo. The aqueous inflow calculation via non-invasive local application of 234.5 mg/ml Gd-DTPA can be assessed by the variability of relative concentration of Gd-DTPA in anterior chamber and ACV in vivo, under anesthetic condition.

Diagnosis and Treatment of Acute Retinal Necrosis: A Report by the American Academy of Ophthalmology.

PURPOSE: To evaluate the available evidence in peer-reviewed publications about the diagnosis and treatment of acute retinal necrosis (ARN). METHODS: Literature searches of the PubMed and Cochrane Library databases were last conducted on July 27, 2016. The searches identified 216 unique citations, and 49 articles of possible clinical relevance were reviewed in full text. Of these 49 articles, 27 were deemed sufficiently relevant or of interest, and they were rated according to strength of evidence. An additional 6 articles were identified from the reference lists of these articles and included. All 33 studies were retrospective. RESULTS: Polymerase chain reaction (PCR) testing of aqueous or vitreous humor was positive for herpes simplex virus (HSV) or varicella zoster virus (VZV) in 79% to 100% of cases of suspected ARN. Aqueous and vitreous specimens are both sensitive and specific. There is level II and III evidence supporting the use of intravenous and oral antiviral therapy for the treatment of ARN. Data suggest that equivalent plasma drug levels of acyclovir can be achieved after administration of oral valacyclovir or intravenous acyclovir. There is level II and III evidence suggesting that the combination of intravitreal foscarnet and systemic antiviral therapy may have greater therapeutic efficacy than systemic therapy alone. The effectiveness of prophylactic laser or early pars plana vitrectomy (PPV) in preventing retinal detachment (RD) remains unclear. CONCLUSIONS: Polymerase chain reaction testing of ocular fluid is useful in supporting a clinical diagnosis of ARN, but treatment should not be delayed while awaiting PCR results. Initial oral or intravenous antiviral therapy is effective in treating ARN. The adjunctive use of intravitreal foscarnet may be more effective than systemic therapy alone. The role of prophylactic laser retinopexy or early PPV is unknown at this time.

Clinical, Pharmacokinetic, and In Vitro Studies to Support Bioequivalence of Ophthalmic Drug Products.

For ophthalmic drug products, the determination of bioequivalence can be challenging, as drug concentrations at the site of action cannot always be measured. The FDA has recommended a variety of studies that can be used to demonstrate bioequivalence for different ophthalmic drug products. Product-specific bioequivalence recommendations for 28 ophthalmic products have been posted on FDA's website as of May 2016, outlining the specific tests which should be performed to demonstrate bioequivalence. The type of study that can be used to demonstrate bioequivalence depends on the drug product's active pharmaceutical ingredient(s), dosage form, indication, site of action, mechanism of action, and scientific understanding of drug release/drug availability and drug product characteristics. This article outlines the FDA's current guidance on studies to demonstrate bioequivalence through clinical endpoint studies, pharmacokinetic studies, and in vitro studies for generic ophthalmic drug products.

Safety of femtosecond laser-assisted cataract surgery: assessment of aqueous humour and lens capsule.

PURPOSE: To investigate the effect of femtosecond laser-assisted cataract surgery (FLACS) on aqueous humour and lens capsule. METHODS: This prospective randomized comparative study enrolled 19 eyes that underwent FLACS as the trial group and 20 eyes that underwent conventional phacoemulsification as the control group. The femtosecond laser platform (LLS-fs 3D; LensAR, Orlando, FL, USA) was used to generate capsulotomy (laser energy 8 µJ) and lens fragmentation (laser energy 10 µJ). Morphology of the cutting edge and cells of anterior capsule was assessed by light microscopy. The proteins in the aqueous humour were identified by mass spectrometry (Ultraflex III TOF/TOF; Bruker Dalton, Bremen, Germany). Electrolyte in the aqueous humour was detected by a chemistry analyzer (Aeroset Clinical Chemistry Analyzer; Abbott Laboratories, Abbott Park, IL, USA). RESULTS: The cutting edge of anterior capsule was saw-tooth-shaped under magnification of 200× and 400× in the trial group, while it was smooth in the control group. Intact cells were found in the boundary area next to the cutting edge of anterior capsule in both groups. ß-Crystallin B1, γ-crystallin S and transferrin were detected in the aqueous humour in the trial group. The concentrations of K+ , Na+ and Cl- in the aqueous humour in the trial group differed significantly from those in the control group (p = 0.02, 0.03 and 0.04, respectively). CONCLUSION: Femtosecond laser-assisted cataract surgery (FLACS) causes release of transferrin and crystallin from lens to aqueous humour and results in significant changes in the concentrations of K+ , Na+ and Cl- in aqueous humour. However, these changes due to FLACS have no clinical significance or toxicity.

[New algorithm of aqueous humor dynamics assessment in glaucoma].

The purpose of the study was to develop a new algorithm of aqueous humor dynamics assessment in glaucomatous eyes, which would take into account the shape of the tonographic curve and individual elastic properties of the corneoscleral capsule. Basic ophthalmic examination supplemented with tonography and differentiated tonometry was performed on 33 patients with primary open-angle glaucoma (POAG), 8 POAG suspects, and 9 healthy controls. Obtained data were processed in accordance with the developed algorithm. A new formula for calculating the coefficient of outflow facility and several additional parameters describing the condition of aqueous pathways were proposed. In POAG patients these parameters significantly differed from those in healthy controls.

[Antibiotic susceptibility patterns of bacteria isolated from keratitis and intraocular infections at Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia]. / Sensibilidad antibiótica de bacterias obtenidas de queratitis e infecciones intraoculares en la Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia.

INTRODUCTION: Bacterial resistance is critical for the selection of antibiotics in the treatment of infections, so it is vital to know its current status in our geographical area. OBJECTIVE: To determine in vitro antibiotic susceptibility of bacterial isolates obtained from keratitis and intraocular infections. MATERIALS AND METHODS: A retrospective study of microbiological tests in Fundación Oftalmológica de Santander (FOSCAL) was carried out between June, 2011, and January, 2012. RESULTS: A total of 92 samples were examined and 110 bacteria, 27 fungi and 12 free-living amoebae were identified. Polymicrobial infections constituted 50% of the total; 1.1%, 0%, 1.1%, 16.9%, 29.3% and 85% of Gram-positive bacteria were resistant to imipenem, moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin and tobramycin, respectively, while 0%, 8.3%, 0%, 0%, 18.2% and 27.3% of Gram-negative bacteria were resistant to imipenem, moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin and tobramycin, respectively. For methicillin-resistant coagulase-positive staphylococci, resistance percentages to imipenem, moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin and tobramycin were 0%, 0%, 0%, 7%, 17% and 100%, respectively. For methicillin-resistant coagulase-negative staphylococci, resistance percentages to imipenem, moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin and tobramycin were 3%, 0%, 0%, 24%, 44% and 100%, respectively. Overall bacterial resistance to imipenem, moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin and tobramycin, for both Gram-positive and Gram-negative, was 1%, 1%, 1%, 15.1%, 28% and 64.5%, respectively. CONCLUSIONS: The levels of bacterial resistance to imipenem, moxifloxacin and gatifloxacin were lower than for levofloxacin, ciprofloxacin and tobramycin. The levels of resistance to tobramycin were very high, which calls into question its usefulness in this region of our country.

Intravitreal docosahexaenoic acid in a rabbit model: preclinical safety assessment.

PURPOSE: The purpose of the present study was to evaluate the retinal toxicity of a single dose of intravitreal docosahexaenoic acid (DHA) in rabbit eyes over a short-term period. METHODS: Sixteen New Zealand albino rabbits were selected for this pre-clinical study. Six concentrations of DHA (Brudy Laboratories, Barcelona, Spain) were prepared: 10 mg/50 µl, 5 mg/50 µl, 2'5 mg/50 µl, 50 µg/50 µl, 25 µg/50 µl, and 5 µg/50 µl. Each concentration was injected intravitreally in the right eye of two rabbits. As a control, the vehicle solution was injected in one eye of four animals. Retinal safety was studied by slit-lamp examination, and electroretinography. All the rabbits were euthanized one week after the intravitreal injection of DHA and the eyeballs were processed to morphologic and morphometric histological examination by light microscopy. At the same time aqueous and vitreous humor samples were taken to quantify the concentration of omega-3 acids by gas chromatography. Statistical analysis was performed by SPSS 21.0. RESULTS: Slit-lamp examination revealed an important inflammatory reaction on the anterior chamber of the rabbits injected with the higher concentrations of DHA (10 mg/50 µl, 5 mg/50 µl, 2'5 mg/50 µ) Lower concentrations showed no inflammation. Electroretinography and histological studies showed no significant difference between control and DHA-injected groups except for the group injected with 50 µg/50 µl. CONCLUSIONS: Our results indicate that administration of intravitreal DHA is safe in the albino rabbit model up to the maximum tolerated dose of 25 µg/50 µl. Further studies should be performed in order to evaluate the effect of intravitreal injection of DHA as a treatment, alone or in combination, of different retinal diseases.

In vivo assessment of aqueous humor dynamics upon chronic ocular hypertension and hypotensive drug treatment using gadolinium-enhanced MRI.

PURPOSE: Although glaucoma treatments alter aqueous humor (AH) dynamics to lower intraocular pressure, the regulatory mechanisms of AH circulation and their contributions to the pathogenesis of ocular hypertension and glaucoma remain unclear. We hypothesized that gadolinium-enhanced magnetic resonance imaging (Gd-MRI) can visualize and assess AH dynamics upon sustained intraocular pressure elevation and pharmacologic interventions. METHODS: Gadolinium contrast agent was systemically administered to adult rats to mimic soluble AH components entering the anterior chamber (AC) via blood-aqueous barrier. Dynamic Gd-MRI was applied to examine the signal enhancement in AC and vitreous body upon microbead-induced ocular hypertension and unilateral topical applications of latanoprost, timolol maleate, and brimonidine tartrate to healthy eyes. RESULTS: Gadolinium signal time courses in microbead-induced hypertensive eyes possessed faster initial gadolinium uptake and higher peak signals in AC than control eyes, reflective of reduced gadolinium clearance upon microbead occlusion. Opposite trends were observed in latanoprost- and timolol-treated eyes, indicative of their respective drug actions on increased uveoscleral outflow and reduced AH production. The slowest initial gadolinium uptake but strongest peak signals were found in AC of both brimonidine-treated and untreated fellow eyes. These findings drew attention to the systemic effects of topical hypotensive drug treatment. Gadolinium leaked into the vitreous of microbead-induced hypertensive eyes and brimonidine-treated and untreated fellow eyes, suggestive of a compromise of aqueous-vitreous or blood-ocular barrier integrity. CONCLUSIONS: Gadolinium-enhanced MRI allows spatiotemporal and quantitative evaluation of altered AH dynamics and ocular tissue permeability for better understanding the physiological mechanisms of ocular hypertension and the efficacy of antiglaucoma drug treatments.