58 research outputs found
Aqueous Humor Cytokines in Patients With Acute Nonarteritic Anterior Ischemic Optic Neuropathy
No full textComparison of corneal endothelial cell analysis in patients with uveitis and healthy subjects
No full textPurposeThe aim of this study is to investigate the effect of uveitis in corneal endothelial cell number and morphology by non-contact specular microscopy.MethodsOur cross-sectional study was performed on 56 eyes of uveitis patients and 53 eyes of healthy subjects. Non-contact specular microscopy was performed to all subjects. The cell density (CD), coefficient of variation, cell minimum area (Min) and cell maximum area (Max), the average of cell size (AVG), percent of hexagonality (HEX%), central corneal thickness (CCT), intraocular pressure (IOP) during uveitis and during remission were measured and compared between two groups.ResultsThe mean endothelial cell analysis of the patients was 2540619 cells/mm(2), and the mean endothelial cell analysis of the control group was 2834 +/- 413 cells/mm(2). The difference was statistically significant between the groups (p=0.01). There was a statistically significant difference between two groups in terms of Max, Min, AVG, and HEX values. However, there was no difference in terms of CCT between two groups. There was a significant negative correlation between CD and IOP during uveitis attack. There was a significant negative correlation between the anterior chamber cell value and CD.Conclusion Our results suggested that uveitis affected endothelial cell density, cell size and shape but not the corneal thickness without being influenced by the duration and number of attacks. Increased IOP during uveitis and anterior chamber cell value had an important role on CD in patients with uveitis
Comparison of corneal endothelial cell analysis in patients with uveitis and healthy subjects
No full textComparison of topical nepafenac 0.1% with intravitreal dexamethasone implant for the treatment of Irvine-Gass syndrome
No full textAIM: To compare safety and efficacy of intravitreal dexamethasone (IVD) implant with topical nepafenac (TN) 0.1% in previously untreated Irvine-Gass syndrome (IGS) in clinical practice. METHODS: This was a retrospective study of 62 eyes with IGS after phacoemulsification with posterior chamber intraocular lens (IOL) implantation. None of the patients used treatment before IVD or TN. Best-corrected visual acuity (BCVA) with Early Treatment Diabetic Retinopathy Study chart (ETDRS), slit-lamp, intraocular pressure (IOP) measurement, fundus examination, spectral-domain optical coherence tomography (OCT) and fundus florescein angiography were performed to all subjects at baseline, 1, 3 and 6mo. RESULTS: The mean BCVA of the IVD group was 49.3 +/- 6.8, and the mean BCVA of the TN group was 32.9 +/- 7.3 ETDRS letters in post-treatment month 6. The mean central macular thickness (CRT) of IVD group was 266.6 +/- 53.5 mu m and the mean CRT of TN group was 364.9 +/- 56.3 mu m in post-treatment month 6. Baseline BCVA has correlation with final BCVA in TN group however there was no correlation between baseline BCVA and final BCVA in IVD group. CONCLUSION: IVD is found to be better than TN in controlling pseudophakic macular edema and improving visual acuity. IVD group also has significantly lower CRT however IOP is not significantly different between two groups in post-treatment month 6
Central Retinal Artery Occlusion in Takayasu’s Arteritis as the First Presentation of the Disease
No full textTakayasu’s arteritis (TA) is a chronic inflammatory granulomatous vasculitis which affects large and medium arterial vessels. The disease involves especially subclavian arteries and aortic branches but it can consist of any arteries. The major pathology is granulomatous panarteritis with intima proliferation and defects of the elastic lamina of the vessels. We present a case of central retinal artery occlusion in TA as the first presentation of the disease. To the best of our knowledge, the present case is the first case that demonstrates central retinal artery occlusion as an initial manifestation in TA. A 48-year-old woman was admitted to our clinic with the complaint of sudden and painless vision loss in her right eye for one day. Although retinal artery involvement is a very rare presentation in TA, it is important to recall TA particularly in young patients with retinal artery occlusion
Autonomous path-to-path movement for a vehicle with mecanum wheels
No full textAutomation has played a big role in the development of the industry in the last century. Despite the desire to automate the tedious and repetitive work in greenhouses by robots, the automation level in the horticulture is still far from desired. However, the last decade shows a lot of progress in the horticulture automation and more is expected due to the increasing need for automated processes in this area. Priva B.V. started the Tomation project in 2002 to automate the task of cutting off the leaves of tomato plants. Cutting off the leaves of tomato plants is one of the crop handling tasks done on a regular basis to ensure optimal growth and ripening of the tomatoes. This report presents research concerning the Tomation Project of Priva B.V., aimed at solving the problem of autonomous movement of the leaf-cutting robot in the greenhouse. The robot has to move autonomously in the path and periodically change from path to path. The focus in this report is on the path-to-path movement in the greenhouse. This is a movement where the vehicle rides off the rail, moves to the next path and finally drives back on the rail again to continue with the leaf cutting process. The robot platform is a vehicle equipped with omni-directional mecanum wheels and powered by stepper motors from Nanotec®. These mecanum wheels are omnidirectional wheels and are able to move the vehicle in a lateral direction. The vehicle will move with mecanum wheels on the concrete path and with flanged wheels on the rail. The vehicle with the mecanum wheels encountered difficulties driving sideways at a critical weight on the platform. Undesired movements occur at these weights, because the stepper motor is not performing all the steps. The scope of the project includes the autonomous path-to-path movement of the robot. The vision system for navigational purposes is not installed yet on the platform. Hence, the inputs from the system are entered manually in this project. It has to be taken into account that the vision system can only look at the front. The path-to-path movement should meet requirements on accuracy, time, speed and the payload of the vehicle. Furthermore, the vehicle has to be able to cope with cracks and obstructions on the road during the movement. Finally, it has to deal with rails that are shifted, because they are not fixed properly on the concrete path. Using the positional feedback of the encoders of the available stepper motor and inputs of a vision system a proper control system is required. To get a good starting point to develop the autonomous movement of the platform, it was important to have a good understanding of the stepper motor and a clear view on the possibilities and modes of use of the motor. The working principle of the stepper motor is explained by describing the common step modes: the full step, the half step and the micro step mode. The difference between the stepper motor and a servo motor is explained. Based on the differences between these motors, the choice on the stepper motor has been reasoned. The technical specifications and the Software Development Kit of the motors are presented. These were needed to learn the possibilities in controlling and using the motors. The mecanum wheels of the vehicle of the Tomation Project serve for omnidirectional purposes. The possibility to move in a lateral direction with these wheels was the main reason for using them. The wheels offer a way to do compact movements on the path, without obstructing the path more than necessary to avoid possible conflicts with other (moving) objects. The omnidirectional movement is realized by appropriately controlling the angular velocity of each wheel separately. Depending on each individual wheel rotation direction and velocity, the resulting combination of the wheels produces a total movement in the desired direction without changing the orientation of the wheels. The navigational purposes of the Tomation project required a proper kinematic model of the vehicle. The equations of motion are used to derive the ideal kinematic model to reach a desired position and orientation. The measured position errors are dealt with by adjusting the kinematic model with experiments. The sources of these errors were slippage, bearing friction and point contact friction. A comprehensive research on rollers of the wheels during omnidirectional movements is performed. This was needed to understand the motion of the rollers and its contribution to the omnidirectional movements. The analyses have shown that as the movement with the vehicle gets more lateral, the rollers will contribute more to the movement. This was also observed during movements of the vehicle. These observations and analyses on the rollers are used to explain the dynamics of the wheels. To understand why the lateral movement of the vehicle needs more phase current than the forward movement, the dynamics of the mecanum wheels are investigated. A misconception in the literature on the dynamic model is explained. The literature neglects the force perpendicular to the rollers without a proper reasoning. The aspect of motion in the rollers is not taken into account. Hence, it is decided to reject the theory in the literature on the dynamics of these vehicles. With observations and analyses on the wheels a new dynamic model has been developed. This model takes also the friction in the rollers into account. This friction causes the main difference between the required force for the forward and lateral movement. It is seen that as the movement gets more lateral, the rollers will have more contribution, so the movement will be more affected by friction. Hence, the lateral movement needs more force to overcome the friction compared to a forward movement. The vehicle of the Tomation project encountered practical problems related to the navigational features of the vehicle. The effects of these problems are analysed and solutions are presented when needed. To navigate properly in the greenhouse a function is developed that provides the number of steps needed per wheel for a given omnidirectional movement. Furthermore, the undesired effects, caused by rounding the target speed of the motor, are dealt with by looking for the nearest movement without these errors. Next, the asynchronous start of the motors caused by the serial connection is solved with an Arduino board that generates a signal to start all the motors simultaneously. Finally, an ultrasonic proximity sensor is used to detect the concrete path when riding off the rail backwards. The vision system could not be used here, since the cameras are facing forward. These functions and additions improve the reliability and robustness of the movement in the greenhouse. With the aforementioned functions and findings from the analyses a reliable and proper path to path movement in the greenhouse is ensured. The movement is split into three separate movements: riding off the rail, moving across to the next path and driving on the rail of the new path. After analysing alternatives for these movements, it has been decided that the vehicle will move just with two motors in the area where transition from the mecanum wheels to the flanged wheels occurs. A lateral movement with the current setup was not feasible for the required payload. If we disregard the payload of the robot, the remaining conditions did meet the requirements of the movement. The research in this project has contributed to the autonomous movement for the vehicle of the Tomation Project of Priva. The path-to-path movement of the vehicle is realized in a reliable way, provided that the motors are strong enough to deliver the required force for the movements. The results will be used for further steps in the project.Mechanical EngineeringDelft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Association of Changes in Thickness of Limbal Epithelial and Stroma with Corneal Scars Detected by High-Resolution Anterior Segment Optic Coherence Tomography
No full textAim To investigate the corneal central and limbal thickness in cornea scar patients using high-resolution anterior segment optical coherence tomography (AS-OCT) and to determine the changes in the limbal region due to the corneal scar. Also, to evaluate tear film parameters in scar patients. Methods Thirty patients with central corneal scar and 30 control subjects. The control subjects were healthy individuals who came to our clinic for routine ophthalmological examination. They were enrolled in this matched case-control study. Central epithelial thickness (ET), stromal thickness (ST), limbal epithelial thickness (LET), and limbal stromal thickness (LST) were analyzed using high-resolution AS-OCT. For evaluation of the ocular surface, the following techniques were used: tear break-up time (BUT) employing standard sterile strips of fluorescein sodium, Schirmer test- I (SCH), and the Ocular Surface Disease Index (OSDI) Questionnaire. Results The mean central ET of the patient group was 51.5 +/- 12.4 mu m, while the mean central ET of the control group was 59.2 +/- 9.0 mu m. There was a statistically significant difference between patients and controls (p = 0.008). The mean LST of the patients was 747.9 +/- 115.7 mu m, and the mean LST of the controls was 726.3 +/- 79.7 mu m. There was a statistically significant difference between patients and controls according to BUT (p = 0.009) and SCH (p = 0.04). However, there was no significant difference between OSDI results of patients and controls (p = 0.08). Conclusion Corneal monitoring with high-resolution AS-OCT is a simple, noninvasive, useful technique for corneal scar patients. Cornea scars cause decreased ET. This result could be associated with lower tear film parameters in scar patients. The scar length is associated with higher intraocular pressure (IOP) values. Decreased LET and increased LST were detected in scar patients
Thickness changes in foveal, macular, and ganglion cell complex regions associated with Behcet uveitis during remission
No full textPurpose: To investigate foveal, macular, and ganglion cell complex (GCC) thickness in patients with Behcet uveitis during remission. Methods: We included patients with panuveitis attacks caused by Behcet disease. Patients were taking immunosuppressive therapy and had no active ocular inflammation. After complete ophthalmologic examination, optical coherence tomography (OCT) was performed with a macula multi-cross protocol. The OCT images were evaluated for structural changes. Patients with no structural changes were imaged with the macula map protocol to obtain parafoveal and perifoveal macular and GCC thicknesses. Patients were compared to an age-matched control group with the Mann-Whitney U test. In correlation analyses, we examined relationships among visual acuity (logMAR), disease duration, and the number of attacks. Results: The study included 27 eyes of 21 patients (mean age 38.14 +/- 9.18 years; mean disease duration 65.4 +/- 74.6 months; mean number of attacks 2.5 +/- 1.9). The OCT showed foveal thicknesses of 260.29 +/- 34.17 mu m in patients and 280.58 +/- 19.54 mu m in controls (p = 0.010). Foveal thickness was not related to visual acuity (p = 0.485), but was negatively correlated to disease duration (p = 0.016) and number of attacks (p = 0.001). Patients and controls showed similar macular thickness in parafoveal quadrants (p = 0.294, p = 0.096, p = 0.88, p = 0.111) and perifoveal quadrants (p = 0.241, p = 0.517, p = 0.53288, p = 0.241). Patient parafoveal GCCs were significantly thinner than in controls in the inferior temporal quadrant (p = 0.041), but not in other quadrants (p = 0.867, p = 0.832, p = 0.390). Patient perifoveal GCCs were significantly thicker than in controls in the superior and inferior temporal quadrants (p = 0.008, p = 0.008) and somewhat thicker (but not significantly) in the superior and inferior nasal quadrants (p = 0.052, p = 0.138). Conclusions: Patients with Behcet uveitis in remission showed insignificant decreases in foveal and macular thickness and significant increases in perifoveal GCC thickness compared to controls. The increased perifoveal GCC thickness may result from macular ischemia persisting in remission
Elevated Neutrophil Lymphocyte Ratio in Recurrent Optic Neuritis
No full textPurpose. To demonstrate the relation between optic neuritis (ON) and systemic inflammation markers as neutrophil lymphocyte ratio (N/L ratio), platelet count, mean platelet volume (MPV), and red cell distribution width (RDW) and furthermore to evaluate the utilization of these markers to predict the frequency of the ON episodes. Methods. Forty-two patients with acute ON and forty healthy subjects were enrolled into the study. The medical records were reviewed for age, sex, hemoglobin (Hb), Haematocrit (Htc), RDW, platelet count, MPV, white blood cell count (WBC), neutrophil and lymphocyte count, and neutrophil lymphocyte ratio (N/L ratio). Results. The mean N/L ratio, platelet counts, and RDW were significantly higher in ON group (p=0.000, p=0.048, and p=0.002). There was a significant relation between N/L ratio and number of episodes (r=0.492, p=0.001). There was a statistically significant difference for MPV between one episode group and recurrent ON group (p=0.035). Conclusions. Simple and inexpensive laboratory methods could help us show systemic inflammation and monitor ON patients. Higher N/L ratio can be a useful marker for predicting recurrent attacks
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