Comparison of Intraocular Pressure Changes Due to Exposure to Mobile Phone Electromagnetics Radiations in Normal and Glaucoma Eye.

PURPOSE: The aim of this study is to investigate the effects of electromagnetic waves (EMWs) emitted by a mobile phone on the intraocular pressure (IOP) in the eyeball. METHODS: This quasi-experimental study was conducted on 166 eyes from 83 individuals in the 40-70 age range who referred to "Khatam-al-Anbia Hospital, Mashhad, Iran" in 2016. There were two groups of participants, and the first one consisted of 41 participants who had normal eyes, whereas the second one comprised 42 participants who suffered from open-angle glaucoma disease. The IOP in both groups was measured and recorded by a specialist before and after talking 5 min on the cellphone with the help of the Goldman method. Statistical analysis such as paired t-test and analysis of variance was performed and all tests are statistically significant at (P < 0.05). For this purpose, the SPSS software (version 16) was applied. RESULTS: IOP in the glaucoma eye (42 eyes) ipsilateral to mobile phone before and after the intervention was 18.64 ± 6.7 and 23.53 ± 6.3, respectively (P < 0.001). However, IOP in the control group (41 eyes) ipsilateral to mobile phone before and after the intervention was 12.95 ± 3.5 and 13.39 ± 2.8, respectively (P = 0.063). IOP change in the opposite glaucomatous eye to mobile phone in glaucoma group (39 eyes) and normal group (44 eyes) was not significantly different before and after the phone call (P = 0.065 and P = 0.85, respectively). CONCLUSION: We found that the acute effects of EMWs emitted from the mobile phones can significantly increase the IOP in glaucoma eye, while such changes were not observed in normal eyes.

Changes in the ABCD Keratoconus Grade After Intracorneal Ring Segment Implantation.

PURPOSE: To assess the changes in the ABCD keratoconus staging system 6 months after intracorneal ring segment implantation. METHODS: Fifty eyes of 50 patients with keratoconus who were implanted with the Keraring (Mediphacos, Belo Horizonte, Brazil) using the femtosecond laser were assessed. Preoperative and postoperative assessments included determination of distance uncorrected visual acuity and distance corrected visual acuity (DCVA), refraction, and Scheimpflug tomography with the Pentacam HR. In the ABCD keratoconus staging system, the elements A, B, C, and D stand for anterior and posterior radii of curvature in a 3.0-mm zone centered on the thinnest point (TP), corneal thickness at the TP, and DCVA, respectively. RESULTS: Keraring implantation produced significant flattening changes (preoperatively vs. postoperatively) in the anterior (6.60 ± 0.48 vs. 7.22 ± 0.57 mm, P < 0.001) and posterior (4.99 ± 0.47 vs. 5.16 ± 0.53 mm, P = 0.002) radii of curvature of the 3-mm zone centered on the corneal TP associated with a statistically significant improvement in the DCVA (0.56 ± 0.24 vs. 0.70 ± 0.22 in the decimal notation, P = 0.001) with no significant change in the corneal thickness at the TP (P = 0.285). The most changes occurred in element A of the ABCD keratoconus classification. Also, a 1-stage change was observed for element B, whereas elements C and D did not show changes in their postoperative stages after ring implantation. ABCD keratoconus staging before ring implantation was A2B3C2D1 and changed to A1B2C2D1 6 months after surgery. CONCLUSIONS: The ABCD staging system provides a more comprehensive guide that better illustrates the structural changes and visual acuity as one aspect of visual function after the implantation of the intrastromal corneal ring segments.

Diagnostic Ability of Corneal Shape and Biomechanical Parameters for Detecting Frank Keratoconus.

PURPOSE: To assess the diagnostic capability of corneal shape and biomechanical parameters for distinguishing normal eyes from frank keratoconus (KCN). METHODS: This is a retrospective analysis of eyes of 137 control subjects and 145 patients with KCN, with one of their eyes randomly selected as the study eye. Corneal biomechanical parameters were assessed using the Corvis ST (Oculus Optikgeräte GmbH) and Oculus Response Analyzer (Reichert Ophthalmic Instruments). Corneal tomography was performed using the Oculus Pentacam. The clinical diagnosis of KCN was based on slit-lamp findings (eg, Fleischer ring, Vogt striae) and abnormal topographic patterns on the sagittal (axial) front curvature map, disregarding tomographic and biomechanical findings. The discriminative ability for each parameter was tested using the Mann-Whitney U test. The accuracy of each parameter with statistically significant differences was determined using receiver operating characteristic curves, which were compared using the DeLong method. RESULTS: Statistically significant differences were observed for all corneal shape and biomechanical parameters tested (P < 0.05) except peak distance at the highest concavity (P = 0.504). The area under the curve (AUC), sensitivity, and specificity for corneal hysteresis (CH) and corneal resistance factor (CRF) were 0.894, 80.7%, and 84.7% and 0.946, 85.5%, and 89.1%, respectively. The dynamic corneal response parameters from the Corvis ST, stiffness parameter at first applanation, integrated radius (IR), and deformation amplitude ratio at 2 mm (DA-2 mm) had AUC, sensitivity, and specificity of 0.965, 86.2%, and 94.9%; 0.961, 87.6%, and 93.4%; and 0.950, 80.7%, and 98.5%. The Corvis biomechanical index had an AUC of 0.998 (95% confidence interval, 0.983-1.000), with 96.6% sensitivity and 99.3% specificity. The Belin-Ambrósio enhanced ectasia deviation index (BAD-Dv3) and the tomographical/biomechanical index (TBI) had an AUC of 1.0 (95% confidence interval, 0.987-1.000), with sensitivity and specificity of 100%. The combined indices, Corvis biomechanical index, BAD-D, and TBI, had a statistically higher AUC than that of all corneal biomechanical parameters (DeLong, P < 0.001). CONCLUSIONS: The Scheimpflug-derived shape and biomechanical parameters are able to accurately distinguish normal corneas from frank (clinical) keratoconic corneas. However, the combined parameters were more effective. Further studies should test milder ectasia cases.

Modeling of thermodiffusion in liquid metal alloys.

In this paper following the linear non-equilibrium thermodynamics approach, an expression is derived for the calculation of the thermodiffusion factor in binary liquid metal alloys. The expression is comprised of two terms; the first term accounts for the thermally driven interactions between metal ions, a phenomenon similar to that of the non-ionic binary mixtures, such as hydrocarbons; the second term is called the electronic contribution and is the mass diffusion due to an internal electric field that is induced as a result of the imposed thermal gradient. Both terms are formulated as functions of the net heats of transport. The ion-ion net heat of transport is simulated by the activation energy of viscous flow and the electronic net heat of transport is correlated with the force acting on the ions by the rearrangement of the conduction electrons and ions. A methodology is presented and used to estimate the liquid metal properties, such as the partial molar internal energies, enthalpies, volumes and the activity coefficients used for model validation. The prediction power of the proposed expression along with some other existing thermodiffusion models for liquid mixtures, such as the Haase, Kempers, Drickamer and Firoozabadi formulas are examined against available experimental data obtained on ground or in microgravity environment. The proposed model satisfactorily predicts the thermodiffusion data of mixtures that are composed of elements with comparable melting points. It is also potentially and qualitatively able to predict a sign change in thermodiffusion factor of Na-K liquid mixture. With some speculation, the sign change is attributed to an anomalous change in thermoelectric power of Na-K mixture with composition.