Background and Objective: One of the most common extracutaneous complications in psoriasis patients is ocular complications, which is controversial concerning its effect on choroidal thickness. This study aimed to compare the psoriasis patients with healthy individuals in terms of the thickness of the choroidal layer using the Optical coherence tomography technique. Materials and Methods: In this case-control study, 30 psoriasis patients were compared with 32 healthy individuals who were matched for gender and age. Choroidal thickness was measured in both groups using the Optical coherence tomography technique. Furthermore, the relationship of the choroidal thickness with the severity and duration of the disease was assessed in patients. Results: The mean choroidal thickness of the left eye (312. 1± 12. 0 mμ vs. 296. 3± 20. 8 mμ ), right eye (310. 6± 12. 5mμ vs. 297. 5± 17. 5mμ ), and regardless of the left or right eye (311. 3± 12. 2 mμ vs. 296. 9± 19. 1mμ ) was significantly higher in patients, compared to the control group (P=0. 001 for all three mean values). No significant relationship was found between disease duration and severity with choroid thickness. Moreover, the patients with multiple limb involvement had a higher mean choroid thickness; however, it was not statistically significant. Conclusion: According to the results of the present study, patients with psoriasis have a greater choroidal thickness, compared to healthy individuals, which is not related to the severity, type of involvement, and duration of the disease.

Background: The symmetricity of even organs of body may help clinicians in the early detection of diseases.So, we estimated the cup-to-disk ratio (CDR) in left and right eyes and checked the symmetricity between the two eyes using the data of Optical coherence tomography (OCT).Methods: In this study, data from 40 normal subjects were used. This data was taken from the 3D-OCT1000 Tapcon model. For estimating CDR in each B-scan, at first the internal limiting membrane (ILM) and retinal pigment epithelium (RPE) layers were extracted; then using the end-point of RPE layer and the depth of cup, the boundary of disk and cup were determined. Finally, CDR of each B-scan was compared point-by-point and the symmetricity parameters were evaluated.Findings: CDRs in the left and right eyes of 40 normal data were investigated locally. We divided optic disk area into three regions named upper, middle and lower. Then, CDR of each region was calculated for left and right eyes of each patient. The local CDR were 0.433±0.0548, 0.432±0.061, and 0.432±0.0635 for the right eyes and 0.441±0.0635, 0.443±0.0731, and 0.417 ± 0.675 for the left eyes in upper, middle and lower regions, respectively. The differences between local CDRs in different regions of the two eyes were 0.0483±0.042, 0.0420±0.039, and 0.067±0.045, respectively.Conclusion: The results of local comparison of CDRs between the left and right eyes indicated that the level of asymmetricity in the lower region of disk was higher than upper and middle regions, and the middle region has the most symmetricity. In addition, in point-by-point symmetricity evaluation of CDRs, the highest level of symmetricity is seen in the second B-scan, near the center of optic disk.

Background: Retina is the innermost tissue in human eye which sends visual information to the brain by means of optic nerve. Designing an intra-retinal layer segmentation method which can detect the retina surfaces properly in the presence of noise and lack of contrast is an important step in ophthalmology. In this study the combination of morphological component analysis (MCA) and dynamic programming (DP) is used automatically for segmentation of Optical coherence tomography (OCT) images.Methods: Data set for this study was 55 samples which were taken from normal people by Topcon OCT-1000.This study had two phases. In MCA phase the image dictionary was created by clustering with eigenvalues (k-SVD), and then the image was decomposed to cartoon and texture parts by selecting proper bases. In the second phase segmentation was done by the dynamic programming (DP) method on cartoon part and the retinal pigment epithelium (RPE), Verhoeff's memberane (VM), outer segment layer (OSL), innercollagenous layer (ICL), inner synaptic layer (ISL), and outer limiting membrane (OLM) layers were detected.Findings: Comparing the obtained results with gold standard (manual segmentation) shows that minimum error belongs to OSL surface and its error in the form of mean±SD (standard derivation) is 0.030±0.167. For other surfaces the error is calculated in this way from left to right for RPE, VM, ICL, ISL, OLM: -0.66±0.33, -0.59±0.31, -1.00±0.49, -1.72±0.61, -1.05±0.51.Conclusion: MCA in combination with DP can work as an automatic method for six lower intra retina layers' segmentation with acceptable accuracy. One of the main advantages of this method is omitting preprocessing phase for segmentation.

Introduction: To evaluate the clera canal diameters at optic nerve head in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using Optical coherence tomography (OCT) and compare the results with fellow eyes and control group.Material and Methods: In a prospective study, optic nerve head OCT was performed in acute phase of NAION.Horizontal and vertical diameters of the scleral canal at optic disc i.e. the termination of the retinal pigment epithelium, were recorded. The data was compared with fellow eyes and an age- and sex-matched normal control group.Results: Thirty eyes of 30 patients and 20 eyes of 20 normal subjects were studied. Scleral canal diameters were the same for normal fellow eyes, optic atrophy fellow eyes and control eyes. Scleral canal diameters of NAION eyes were significantly greater than control and normal fellow eyes (P<0.001), however, the difference was not significant for optic atrophy fellow eyes.Conclusion: Although in the acute phase, the scleral canal diameters were greater in NAION eyes, no significant difference was found between normal fellow eyes and control eyes.

Background and Objective: Diabetic macular edema (DME) is one of the common complications of diabetes which significantly accounts for preventable visual impairment and blindness. Central macular thickness (CMT) is a feature found in DME patients. This study aims to determine the relationship between Optical coherence tomography (OCT)-measured CMT and visual acuity (VA) in patients with DME before and after intravitreal injection of bevacizumab. Methods: This cross-sectional study was conducted on 100 patients with diabetic macular edema with involvement of both eyes referred to the Ophthalmology Department of Rouhani Hospital in Babol who underwent intravitreal injection of Bevacizumab. VA (measured by Snellen chart), CMT (measured by OCT), clinical and paraclinical factors (including the duration of diabetes, glycosylated hemoglobin (HbA1c), fasting blood sugar (FBS), hypertension, and smoking history data) were evaluated and compared among all patients just before and 45 days after Bevacizumab injection. Findings: Before the injection of Bevacizumab in 200 eyes, the mean value of VA (letter score) and mean value of CMT (µm) were 36.83±12.73 and 425.48±85.18 µm, respectively (p<0.001, 95% CI=12.5 – 17.5 and 95% CI=-71.5 – -55.5, respectively). 45 days after Bevacizumab injection, the mean value of absolute VA changes was 15.24±10.16, and the mean value of absolute CMT changes was -67.83±43.08 µm (coefficient=-0.18, 95% CI=-0.39 – 0.05). Conclusion: Although VA was correlated moderately with CMT and the polynomial regression model enhanced the predictive ability, it remains fully obvious that CMT and clinical factors could play an essential role as VA surrogates.

Purpose: OCT is able to determine the optic disc margin automatically. The aim of this study was to evaluate of the automatic OCT Optic nerve head measurements and compared it with manual tracing results.Materials & Methods: This was a cross-sectional, retrospective study. 31 patients evaluated with OCT for analysis of optic nerve head. 19 eyes having glaucoma, 9 eyes with glaucoma suspect, 3 normal eyes were entered to study. The standard test for glaucoma was clinical examination and visual field evaluation. The optic nerve head analysis was done with OCT-2 and optic nerve head parameter compared with automatic and manual disc margin detection.Results: Significant differences were found between most OCT optic nerve head automated and manual disc assessment parameters, however, good agreement was found between the two methods for all parameters (Intraclass Correlation, 0.71 to 0.94).Areas under receiver operator characteristic curves for clinical examination and visual field analysis were similar for all parameters with both methods in glaucomatous and nonglaucomatous groups.Conclusion: Automated OCT optic nerve head analysis may be used in glaucoma and other clinical optic nerve head abnormalities.In manual disc margin detection, significant differences were detected in the mean measurements between observers but, they demonstrated good inter observer agreement (ICC=0.86 to 0.97).Therefore, the automatic optic nerve head measurements are in agreement with the result obtained by manual detection of the disc margin, but the actual measures are not interchangeable.In ROC curve analysis, manual determination of the disc margin did not improve the ability to distinguish between groups for either the clinical assessment or the visual field analysis.Thus, the automatic optic nerve head analysis can be used in the clinical setting but the normal range of optic disc parameters in different age group was not determined and should be evaluated with caution when compared with population study results.

In recent years, Optical neural networks have received a lot of attention due to their high speed and low power consumption. However, these networks still have many limitations. One of these limitations is implementing their nonlinear layer. In this paper, the implementation of nonlinear unit for an Optical convolutional neural network is investigated, so that using this nonlinear unit, we can realize an all-Optical convolutional neural network with the same accuracy as the electrical networks, while providing higher speed and lower power consumption. In this regard, first of all, different methods of implementing Optical nonlinear unit are reviewed. Then, the impact of utilizing saturable absorber, as the nonlinear unit in different layers of CNN, on the network’, s accuracy is investigated, and finally, a new and simple method is proposed to preserve the accuracy of the Optical neural networks utilizing saturable absorber as the nonlinear activating function.

In this paper, stray lights in Optical system of remote sensing satellite camera is simulated. For this purpose, stray lights, sources of production and their destructive effects on the image quality is studied. Moreover, mechanisms to deal with these unwanted lights are presented. Then, the effect of Optical housing and surface coatings on the performance of stray light in satellite camera, has been studied by the results of the simulation. Finally an optimal design includes a set of different techniques for improving the performance of the considered camera was selected. Simulation results show that by this method, at large angles, stray lights can be completely eliminated whereas at angles near the FOV, stray lights intensities can be very much reduced namely up to 100000 times of their original intensity without almost no serious disturbance in the camera’s field of view.