Real-Time Thickness Measurement of Marine Oil Spill by Fiber-Optic Surface Plasmon Resonance Sensors

Rapid detection of marine oil spills is becoming increasingly critical in the face of frequent marine oil spills. Oil slick thickness measurement is critical in the hazard assessment of such oil leaks. As surface plasmon resonance (SPR) sensors are sensitive to slight changes in refractive index, they can monitor offshore oil spills arising from significant differences in the refractive index between oil and water. This study presents a gold-film fiber-optic surface plasmon resonance (FOSPR) sensor prepared by polydopamine accelerated wet chemical plating for rapid and real-time measurement of oil slick thickness. We examined oil thickness detection at two interfaces, namely, water-oil and air-oil. Detection sensitivity of −1.373%/mm is obtained at the water-oil interface in the thickness range of 0–5 mm; detection sensitivity of −2.742%/mm is obtained at the air-oil interface in the thickness range of 0–10 mm. Temperature and salinity present negligible effects on the oil slick thickness measurement. The fabricated FOSPR sensor has the ability to detect the presence of oil as well as quantify the oil thickness. It has favorable repeatability and reusability, demonstrating the significant potential for use in the estimation of marine oil slick thickness.

Brain magnetic resonance imaging surface-based analysis and cortical thickness measurement in relapsing remission multiple sclerosis

Background Damage occurs in the brain tissue in MS which appears normal on standard conventional imaging (normal appearing brain tissue). This slow, evolving damage can be monitored by nonconventional advanced MR imaging techniques. New techniques for the measurement of cortical thickness have been validated against histological analysis and manual measurements. The aim of our study was to study the role of MRI surface-based analysis and cortical thickness measurement in the evaluation of patients with Relapsing Remitting Multiple Sclerosis and to detect if there is localized rather than generalized cortical atrophy in Multiple Sclerosis patients and correlating these findings with clinical data. Results 30 patients and 30 healthy control were included in this study and they were subjected to cortical thickness analysis using MRI. The patients in our study showed decreased thickness of the precentral, paracentral, postcentral, posterior cingulate cortices and mean cortical thickness in both hemispheres when compared with the normal control group. Statistical analysis was significant (P value < 0.05) for the precentral, paracentral, postcentral, posterior cingulate cortices and mean cortical thickness in both hemispheres. On the other hand, statistical analysis was not significant (P value > 0.05) for other cortices. There was a significant negative correlation between the precentral, paracentral, postcentral, posterior cingulate cortices and mean cortical thickness in both hemispheres and EDSS scores with correlation coefficients ranging from − 0.9878 to − 0.7977. Conclusions MRI and post-processing segmentation analysis for cortical thickness is non-invasive imaging techniques that can increase the level of diagnostic confidence in diagnosis of MS patients and should be included as routine modality when evaluating patients with MS.

CENTRAL MACULAR THICKNESS AFTER CATARACT SURGERY IN NON-DIABETICS AND DIABETICS WITHOUT RETINOPATHY

Objective: To determine the mean change in central macular thickness after cataract surgery and to compare the mean change in central macular thickness after cataract surgery in non-diabetics and diabetics without diabetic retinopathy Study design: Case control Study settings and duration: A case control study was carried out at Ophthalmology department, POF hospital, Wah Cantt. Study duration was 6 months (April 2019-September 2019) Material and methods: A sample size of 60 patients was calculated by using Open Epi Software. We used non probability consecutive sampling. Patients were divided into two groups; Cases (Diabetic) and controls (non-Diabetic). All patients underwent phacoemulsification and observed after 4 weeks for macular thickness measurement using optical coherence tomography before and after surgery. Data analysis was done with SPSS version 20. Post stratification t test was applied. P value ≤0.05 was considered significant. Results: Total 60 patients were included. Mean age of patients was 65.31 ±7. 63SD.There were 35 (58.3%) males and 25 (41.7%) female patients in the study. We found a significant increase in central macular thickness in cases and controls [(223.100±15.86SD vs 227.2667±17.9SD, p=0.000) and (221.200±12.16SD vs 226.289±16.7861SD, p =0.001)] before and after phacoemulsification in cases and controls respectively. However, no significant difference was found between the groups (p=0.486). Conclusion: Central macular thickness was increased after uncomplicated phacoemulsification in both diabetics and non-diabetics without retinopathy for up to a follow-up period of 4 weeks but the thickness did not differ between the two groups.

The diagnostic accuracy and prognostic value of OCT for the evaluation of the visual function in children with a brain tumour: A systematic review

Purpose To systematically review the evidence on the diagnostic accuracy and prognostic value of retinal optical coherence tomography (OCT) to detect visual acuity (VA) or visual field (VF) loss in children with a brain tumour. Methods PubMed, Embase and Cochrane Library databases were searched from inception to February 2021. We included studies evaluating retinal OCT and standard visual function parameters (VA and or VF) in children with a brain tumour. Two authors independently extracted data from each included study. They also assessed the methodological quality of the studies using the QUADAS-2 or QUIPS tool. The diagnostic accuracy of OCT was evaluated with receiver operating characteristic analysis, sensitivity, specificity, positive predictive value and negative predictive value. The prognostic value of OCT was evaluated with predictive measures (odds ratio). Results We included five diagnostic studies, with a total of 186 patients, all diagnosed with optic pathway glioma. No prognostic studies were eligible for inclusion. Included studies evaluated either retinal nerve fiber layer (RNFL) thickness or ganglion cell layer—inner plexiform layer (GCL-IPL) thickness. There was considerable heterogeneity between OCT devices, OCT protocols, visual function parameters and threshold values. Sensitivity and specificity for RNFL thickness measurement ranged from 60.0% to 100.0% and 76.6% to 100%, respectively. For GCL-IPL thickness measurement, area under the curve ranged from 0.91 to 0.98 for different diameters. Conclusion The literature regarding the diagnostic accuracy and prognostic value of OCT parameters in children with a brain tumour is scarce. Due to heterogeneity and a considerable risk of bias of included studies, we cannot draw solid conclusions regarding the accuracy of retinal OCT. Future research should investigate the potential of OCT as diagnostic and prognostic tool for the evaluation of the visual function and detection of visual impairment in children with any type of brain tumour.

Analysis of Ocular Biometric Parameters in Patients with Cystoid Macular Edema

Relevance. Cataract surgeries are among the most frequently performed ophthalmic surgeries in the world. Despite the fact that they become less traumatic every year, such interventions are still accompanied by post-surgery complications, one of which is cystic macular edema (CME) or Irwin–Gass syndrome. Purpose. To analyze ocular biometric parameters in patients with CME. Material and Methods. The study included 40 patients (40 eyes) with post-surgery CME. All patients underwent ultrasound biometry, axial length measurement, crystalline lens thickness measurement with Bio&Pachy Meter AL-4000 (Tomey, Japan) and optical coherence tomography (OCT) with Cirrus HD-OCT 5000 (Carl Zeiss, Germany) to assess central foveal thickness. Depending on the axial length, all eyes were divided into “long” and “short” relative to the average axial length of 23.3 mm. The data was analyzed with STATISTICA 10 software (StatSoft Inc., USA). Results. The incidence of CME after uncomplicated cataract surgery in Cheboksary branch of the S. Fyodorov Eye Microsurgery Federal State Institution amounted to 0.002%. Axial length among patients with CME ranged from 20.53 mm to 25.4 mm; the average value amounted to 22.67 ± 1.05 mm. The majority of eyes were “short” – 31 eyes (77.5%), whereas 9 eyes (22.5%) were “long”. “Short” eyes exhibited a greater crystalline lens thickness (4.81 ± 0.53 mm) compared to “long” eyes (4.42 ± 0.42 mm) (рM-U = 0.014). Conclusion. The development of CME after uncomplicated cataract surgery is more often observed in eyes with axial length smaller than 23.3 mm.