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.

Background: Multiple sclerosis (MS) is a chronic neurodegenerative disease that damages myelinated fibers within the central nervous system. Data obtained using optical coherence tomography (OCT) have recently been identified as a potential biomarker for this disease. We aimed to measure circumpapillary retinal nerve fiber layer thickness (cpRNFLT) using OCT and to compare the results in healthy participants with those of individuals having clinically definitive MS with and without a history of optic neuritis. Methods: This cross-sectional study recruited patients with clinically confirmed MS, with and without optic neuritis, and healthy individuals as a control group. We documented demographic characteristics, duration of MS, and time elapsed since the episode of optic neuritis. All participants underwent a thorough ocular examination and measurement of total, superior, and inferior cpRNFLT using swept-source OCT. Results: In participants with MS, women outnumbered men in the subsets with (90%) and without (64%) optic neuritis. The control group comprised approximately similar numbers of men and women. There was a statistically significant difference in total, superior, and inferior cpRNFLT between study groups (all P < 0. 001). Pairwise comparisons revealed significantly thinner total, superior, and inferior cpRNFLTs in patients having MS with and without (all P < 0. 001) optic neuritis when compared with the controls. We found significantly higher total, superior, and inferior cpRNFLTs in women than in men (all P < 0. 05). However, we found no significant correlation between total, superior, or inferior cpRNFLT and patient age, duration of MS, or time elapsed since the optic neuritis episode (all P > 0. 05), except for a significant moderate inverse correlation between patient age and total cpRNFLT (r =-0. 41,P < 0. 05), indicating a loss of total cpRNFLT with age. Conclusions: Patients with clinically confirmed MS, with or without optic neuritis, had a significantly decreased cpRNFLT compared to that of healthy individuals. There was a significant inverse correlation between age and total cpRNFLT and a difference in cpRNFLT between the sexes, indicating that age and sex may influence the measurement of cpRNFLT using OCT in patients with MS. As a screening tool, OCT should be used along with other existing diagnostic modalities for patients with definite or suspected MS. Further longitudinal studies including various classifications of MS with or without isolated episodes of optic neuritis, along with diagnostic accuracy studies, could provide more robust conclusions on the suitability of OCT as a biomarker of MS.

We performed a comprehensive search of the published literature in PubMed and Google Scholar to identify types, prevalence, etiology, clinical impact, and current methods for correction of various artifacts in optical coherence tomography angiography (OCTA) images. We found that the prevalence of OCTA image artifacts is fairly high. Artifacts associated with eye motion, misidentification of retinal layers, projections, and low optical coherence tomography signal are the most prevalent types. Artifacts in OCTA images are the major limitations of this diagnostic modality in clinical practice and identification of these artifacts and measures to mitigate them are essential for correct diagnosis and follow-up of patients.

Structural glaucomatous changes occur more frequently in the earlier stages of glaucoma than functional defects, so we should give special care to optical coherence tomography (OCT) importance as the best current method. The retinal nerve fiber layer (RNFL) change detection is more useful in early glaucoma, the ganglion cell complex (GCC) in moderate to advanced glaucoma, while the visual field test is more useful in advanced stages, but overall, using a combination of RNFL, optic nerve head (ONH), and macular thickness measurement modalities is recommended for glaucoma evaluation because each parameter may be affected earlier than the others so, considering the findings from the RNFL, ONH, and macula enhances early diagnosis of glaucoma.

Purpose: To identify and explain different artifacts in macular optical coherence tomography (OCT). Methods: For this comprehensive review, a PubMed and Google Scholar (January 1995– October 2018) search was conducted by the researchers, using the keywords such as OCT, artifacts, artefact, and macula. Results: We reviewed the main OCT artifacts including software break-down or misidentification of retinal layers, incomplete segmentation error, complete segmentation failure, mirror artifact (inverted artifact), cut edge artifact, degraded image scan, out‑ of‑ register artifact, off‑ center artifact, motion artifact, foveal duplication, segmentation shift, blink artifact, static or fixed image artifact, linear artifact, and perfluorocarbon liquid‑ producing artifact. Conclusions: There are various artifacts in OCT image scans. The identification of these artifacts may help in accurate interpretations of OCT images in clinical settings that can affect the diagnosis and management of different retinal disorders.