Evaluation of Asymmetry in Right and Left Eyes of Normal Individuals Using Extracted Features from Optical Coherence Tomography and Fundus Images.

BACKGROUND: Asymmetry analysis of retinal layers in right and left eyes can be a valuable tool for early diagnoses of retinal diseases. To determine the limits of the normal interocular asymmetry in retinal layers around macula, thickness measurements are obtained with optical coherence tomography (OCT). METHODS: For this purpose, after segmentation of intraretinal layer in threedimensional OCT data and calculating the midmacular point, the TM of each layer is obtained in 9 sectors in concentric circles around the macula. To compare corresponding sectors in the right and left eyes, the TMs of the left and right images are registered by alignment of retinal raphe (i.e. diskfovea axes). Since the retinal raphe of macular OCTs is not calculable due to limited region size, the TMs are registered by first aligning corresponding retinal raphe of fundus images and then registration of the OCTs to aligned fundus images. To analyze the asymmetry in each retinal layer, the mean and standard deviation of thickness in 9 sectors of 11 layers are calculated in 50 normal individuals. RESULTS: The results demonstrate that some sectors of retinal layers have signifcant asymmetry with P < 0.05 in normal population. In this base, the tolerance limits for normal individuals are calculated. CONCLUSION: This article shows that normal population does not have identical retinal information in both eyes, and without considering this reality, normal asymmetry in information gathered from both eyes might be interpreted as retinal disorders.

Short-Term Effects of Photodynamic Therapy on Segmentation of Retinal Layers in Central Serous Chorioretinopathy.

BACKGROUND: The present study aims to evaluate the effect of photodynamic therapy (PDT) on the thickness of segmentation layers of the retina in cases with central serous chorioretinopathy (CSCR). MATERIALS AND METHODS: This was a prospective, observational study on cases with CSCR who were candidates for PDT therapy. All patients had undergone at least 1 month of conservative management without satisfactory resolution. PDT was carried out according to the safe half-dose therapy scheme. Spectral-domain optical coherence tomography was employed to evaluate the changes in morphology and segmentation of retinal layers. Patients were followed up for 3 months. RESULTS: Twenty-seven cases (18 males and 9 females) were included. Age of the patients varied from 39 to 59 years (mean: 46.61 ± 12.48 years). Cases were followed for 92.17 ± 3.28 days. Sixteen cases had functional and anatomical improvement by the treatment. Changes in overall retinal (377.39 ± 61.36 to 323.61 ± 71.36; P = 0.004) and all outer retinal segmentation layers including outer plexiform layer (34.93 ± 10.07 to 29.25 ± 6.12; P = 0.008), outer nuclear layer (63.52 ± 30.44 to 46.44 ± 20.62; P = 0.017), and retinal pigment epithelium (40.66 ± 37.73 to 23.78 ± 29.33; P = 0.016) were statistically significant. On the contrary, inner retinal segmentation layers, especially retinal ganglion cell (RGC) layer (38.29 ± 16.63 to 37.26 ± 16.18; P = 0.387), remained statistically unchanged. CONCLUSION: We postulate that PDT alleviates outer retinal edema where fluid accumulation occurs mostly, whereas it does not alter inner retinal and especially RGC layer. These findings may indicate that short-term atrophy of the inner retina did not occur following PDT and may point toward safety of this method for cases with CSCR.

Analysis of Fundus Fluorescein Angiogram Based on the Hessian Matrix of Directional Curvelet Sub-bands and Distance Regularized Level Set Evolution.

This paper presents a new procedure for automatic extraction of the blood vessels and optic disk (OD) in fundus fluorescein angiogram (FFA). In order to extract blood vessel centerlines, the algorithm of vessel extraction starts with the analysis of directional images resulting from sub-bands of fast discrete curvelet transform (FDCT) in the similar directions and different scales. For this purpose, each directional image is processed by using information of the first order derivative and eigenvalues obtained from the Hessian matrix. The final vessel segmentation is obtained using a simple region growing algorithm iteratively, which merges centerline images with the contents of images resulting from modified top-hat transform followed by bit plane slicing. After extracting blood vessels from FFA image, candidates regions for OD are enhanced by removing blood vessels from the FFA image, using multi-structure elements morphology, and modification of FDCT coefficients. Then, canny edge detector and Hough transform are applied to the reconstructed image to extract the boundary of candidate regions. At the next step, the information of the main arc of the retinal vessels surrounding the OD region is used to extract the actual location of the OD. Finally, the OD boundary is detected by applying distance regularized level set evolution. The proposed method was tested on the FFA images from angiography unit of Isfahan Feiz Hospital, containing 70 FFA images from different diabetic retinopathy stages. The experimental results show the accuracy more than 93% for vessel segmentation and more than 87% for OD boundary extraction.

Ocular manifestations in a child with systemic brucellosis.

Brucellosis is a zoonotic disease with widespread prevalence. It presents with in various range and often with the presence of non-specific clinical signs and symptoms. Brucellosis also may cause different manifestations in eyes such as uveitis, keratitis, conjunctivitis and neuro-ophthalmic defects. Ocular brucellosis is rare among children. Herein, we present a 7-year-old girl with systemic and ocular brucellosis. After treatment with systemic steroid and antibiotics, her signs and symptoms disappeared. Since early treatment is important in preventing permanent visual loss and the other complications of ocular brucellosis, examination of the eyes in brucellosis patients must always be noticed by clinicians working in this field.

Integrated surgical emergency training plan in the internship: A step toward improving the quality of training and emergency center management.

INTRODUCTION: In this study, by using a problem-oriented approach in the needs assessment, identifying the defects and deficiencies in emergency health training centers has been determined as the basis for the requirements. The main objective of the study was the implementation of surgical emergencies integration of the five surgical groups (general surgery, urology, orthopedics, neurosurgery, and ENT) to meet the needs and determining its efficacy. MATERIALS AND METHODS: THIS INTERVENTIONAL STUDY WAS CONDUCTED IN THREE PHASES: (1) Phase I (design and planning): Needs assessment, recognition of implementation barriers and providing the objectives and training program for integrated emergencies. (2) Phase II (implementation): Justification of the main stakeholders of the project, preparation of students' duties in the emergency department, preparation of on-duty plans, supervising the implementation of the program, and reviewing the plan in parallel with the implementation based on the problems. (3) Phase III (evaluation): Reviewing the evidences based on the amount of efficiency of the plan and justification for its continuation. In the first and the second phase, the data were collected through holding focus group meetings and interviews. In the third phase, the opened-reply and closed-reply researcher-made questionnaires were used. The questionnaire face and content validity were confirmed by experts and the reliability was assessed by calculating the Cronbach's alpha. RESULTS: ACCORDING TO THE VIEWS OF THE INTERNS, ASSISTANTS, TEACHERS, AND EMERGENCY PERSONNEL, THE POSITIVE FEATURES OF THE PLAN INCLUDED THE FOLLOWING: Increasing the patients' satisfaction, reducing the patients' stay in the Emergency Department, increasing the speed of handling the patients, balancing the workloads of the interns, direct training of interns by young teachers of emergency medicine, giving the direct responsibility of the patient to the intern, practical and operational training of emergency issues, increasing the teamwork, facing a variety of patients, practicing the role of general practitioners, role-playing on a real patient's bedside, having a multilateral approach to the patient, reducing the wasting time on minor wards, balancing the work and rest schedules of the interns, and better learning and satisfaction of the interns. Over 60% of the participants believed the program has the following benefits: More attention on the training plan, improving the learning of patient management, being more responsive for the training of interns, increasing operational approach to emergency patients, being more aware of the performed actions, and increasing the quality and speed of services provided to patients. The mean score assigned to the whole questionnaire of investigating the viewpoints was 37.5 out of 50. The mean score of the interns' questionnaire was significantly more than the mean score of the assistants. DISCUSSION: The results obtained indicated that the greatest existing consensus about this plan was the positive impact on the learning of interns in the emergency setting. Thus, it will not only increase the number of patients who the interns are managing during the internship course, but also increases the balance of their workload and they can learn and manage the emergency patients with more leisure.

Diabetic retinopathy grading by digital curvelet transform.

One of the major complications of diabetes is diabetic retinopathy. As manual analysis and diagnosis of large amount of images are time consuming, automatic detection and grading of diabetic retinopathy are desired. In this paper, we use fundus fluorescein angiography and color fundus images simultaneously, extract 6 features employing curvelet transform, and feed them to support vector machine in order to determine diabetic retinopathy severity stages. These features are area of blood vessels, area, regularity of foveal avascular zone, and the number of micro-aneurisms therein, total number of micro-aneurisms, and area of exudates. In order to extract exudates and vessels, we respectively modify curvelet coefficients of color fundus images and angiograms. The end points of extracted vessels in predefined region of interest based on optic disk are connected together to segment foveal avascular zone region. To extract micro-aneurisms from angiogram, first extracted vessels are subtracted from original image, and after removing detected background by morphological operators and enhancing bright small pixels, micro-aneurisms are detected. 70 patients were involved in this study to classify diabetic retinopathy into 3 groups, that is, (1) no diabetic retinopathy, (2) mild/moderate nonproliferative diabetic retinopathy, (3) severe nonproliferative/proliferative diabetic retinopathy, and our simulations show that the proposed system has sensitivity and specificity of 100% for grading.

Cefazolin-Gentamicin versus Vancomycin-Ceftazidime Eye Drops for Bacterial Corneal Ulcers;a Randomized Clinical Trial.

PURPOSE: To compare the efficacy of topical cefazolin-gentamicin versus vancomycinceftazidime for treatment of bacterial corneal ulcers. METHODS: This randomized double-masked clinical trial was performed on consecutive patients with bacterial corneal ulcers referred to Feiz Hospital, Isfahan, Iran from 2004 to 2005. Patients were randomly assigned to cefazolin-gentamicin or vancomycin-ceftazidime eye drops in a masked fashion. Outcome measures included time for resolution of stromal infiltration, re-epithelization of the epithelial defect, and clearance of anterior chamber inflammation as well as culture results and complications. RESULTS: The study included 89 eyes of 89 patients with bacterial corneal ulcers consisting of 57 (64%) male and 32 (36%) female subjects. Specimens were culturenegative in 46% of cases. Forty-one eyes received cefazolin-gentamicin and 48 eyes were treated with vancomycin-ceftazidime. Time for resolution of stromal infiltration was 17.7± 4.3 days versus 13.8± 3.6 days (P=0.04), time to complete re-epithelization was 13.2± 3.1 days versus 9.6± 2.7 days (P=0.01) and time for clearing of the anterior chamber was 11.6± 2.9 days versus 8.1± 2.3 days (P=0.04) in the cefazolin-gentamicin and vancomycin-ceftazidime groups, respectively. The most common complaint related to the medications was ocular burning in 73.1% of patients treated with cefazolingentamicin and 62.9% of cases receiving vancomycin-ceftazidime (P=0.007). CONCLUSION: Vancomycin-ceftazidime eye drops seem to be more effective than cefazolin-gentamicin eye drops for the treatment of bacterial corneal ulcers and are probably better tolerated locally.

Ocular disorders in renal transplant patients.

This cross-sectional study was performed to determine ocular findings in renal transplant recipients and to correlate them with certain clinical characteristics related to transplantation. The study was performed on 150 patients who had received a renal transplant at least three months earlier and had serum creatinine levels < 3 mg/dL. All patients underwent a complete ophthalmologic examination. Clinical variables studied related to the transplant included cause of renal failure, duration of hemodialysis prior to transplantation and immunosuppressive regimen. Overall, 91 male and 59 female subjects with a mean age of 39.9 +/- 17.7 years were included. At least one ocular abnormality could be detected in 89.3% including impaired visual acuity < or = 20/25 (48.6%), conjunctival degeneration in the palpebral fissure (36.6%), posterior sub-capsular cataracts (24%), pinguecula (17.3%), retinal pigment epitheliopathy (14%), arteriovenous crossing changes (8.6%), proliferative diabetic retinopathy (6%), central serous chorioretinopathy and retinal vein occlusions (each in 3.3%), and non-proliferative diabetic retinopathy, optic nerve atrophy and diabetic macular edema (each in 2.7%). Abnormal ocular findings were not correlated with the underlying renal disorder or use of cyclosporine and prednisolone; however, they were positively correlated with transplant duration, pre-transplant dialysis duration and usage of azathioprine or mycophenolate mofetil. Our study suggests that ocular disorders are frequent among renal transplant patients especially with older transplants and those with a longer period of pre-transplant hemodialysis.

Stereoacuity following LASIK.

PURPOSE: To evaluate the effect of laser in situ keratomileusis (LASIK) on stereoacuity (SA). METHODS: This prospective study includes 200 patients scheduled for LASIK. SA was evaluated preoperatively and one week, one month and three months postoperatively using the Random Dot test. Patients with preoperative SA worse than 480 sec/arc were excluded from the study. RESULTS: The study included 138 female (69%) and 62 male (31%) subjects. Spherical equivalent was -0.5 to -12.0 D. Mean preoperative SA was 124.80±124.64 (range 480-15) sec/arc which deteriorated to 138.30±126.48 sec/arc one week after surgery (P=0.158) but improved to 111.30±112.15 sec/arc (P=0.002) one month and 103.65+112.20 sec/arc (P=0.001) three months postoperatively. Overall, stereoacuity decreased in 9.5%, increased in 32.5% and remained unchanged in 58% of patients (P=0.007). Patients with anisometropia had worse SA; eventually, SA increased in 5 non-amblyopic anisometropic patients. CONCLUSION: Despite the overall improvement in mean SA after LASIK, a minority of patients experienced decreased SA. Anisometropic patients without amblyopia seem to have a chance for improved SA after LASIK.