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    Clearance of Intravitreal Daptomycin in Uveitis-Induced Rabbit Model
    (Taylor & Francis Inc, 2015) Ozcimen, Muammer; Sakarya, Yasar; Ozcimen, Serap; Sakarya, Rabia; Goktas, Sertan; Iyisoy, Sinan; Alpfidan, Ismail
    Purpose: To investigate the elimination rate of daptomycin after intravitreal injection in uveitis-induced rabbits. Materials and methods: Intravitreal injection of the single dose of 200 mu g/0.05mL daptomycin was administered to rabbits starting 24 h after induction of uveitis by an intravitreal endotoxin injection. Aqueous humor and vitreous humor samples of eight eyes per time point were collected at selected time intervals (1, 3, 6, 24, 48, 72 and 96 h), and the in vitreous half-life was calculated. Daptomycin concentrations in vitreous and aqueous humor were assayed with high-performance liquid chromatography. Results: The vitreous concentration was noted to decline slowly with time. The mean vitreous concentration was 23.25 +/- 10.99 mu g/mL and 11.10 +/- 3.33 mu g/mL at 96 h in inflamed and normal eyes, respectively. The vitreous daptomycin concentration showed an exponential decay with a half-life of 25.67 h in normal eyes and 34.6 h in inflamed eyes. The aqueous levels of daptomycin in normal eyes were low but remained significantly higher than those of inflamed eyes. Conclusions: Given that the injected dose corresponds to several times the minimum inhibitory concentrations of organisms most involved in endophthalmitis, and that therapeutic levels are present up to 96 h after injection, intravitreal daptomycin should be considered for the treatment of endophthalmitis caused by Gram-positive bacteria.
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    Daptomycin versus Vancomycin in an Enterococcus faecalis Endophthalmitis Rabbit Model
    (Taylor & Francis Inc, 2016) Ozcimen, Muammer; Kurtoglu, Muhammet G.; Goktas, Sertan; Omeroglu, Ethem; Sakarya, Yasar; Alpfidan, Ismail; Ozcimen, Serap
    Purpose: To compare bactericidal activities of daptomycin (DAP) and vancomycin (VAN) in an experimental rabbit model of Enterococcus faecalis endophthalmitis. Materials and methods: The right vitreous cavities of 24 New Zealand rabbits were inoculated with 100 colony-forming units of E. faecalis; and after 24 h, rabbits were randomly divided into three groups. DAP group (n = 8, 0.2 mg/0.05 ml intravitreally), VAN group (n = 8, 1 mg/0.05 ml intravitreally) and balanced salt solution group (BSS, n = 8, 0.05 ml intravitreally). Clinical examination scores were recorded, and vitreous aspirates were obtained for microbiological analysis on days 0, 1, 2, 3 and 4. Rabbits were sacrificed, and the eyes were enucleated for histopathological assessment. Results: There was no difference between the DAP, VAN and BSS groups in terms of the clinical grading of endophthalmitis 24 h after the inoculation. The bacterial counts were similar between the VAN and DAP groups except on day 1, where it was significantly lower than those in the VAN group (p = 0.003). On day 4, 62% of the eyes treated with DAP, and 50% of the eyes treated with VAN were sterilized. All of the eyes from the BSS group showed increasing bacterial growth from day 0 to day 4. There was no difference between the DAP and VAN groups in terms of the histopathological and clinical examination scores, while they were significantly lower than those in the BSS group. Conclusions: This study demonstrates evidence of the effectiveness of DAP for the treatment of experimental E. faecalis endophthalmitis.
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    Effect of Nepafenac Eye Drops on Pain Associated With Pterygium Surgery
    (Lippincott Williams & Wilkins, 2015) Ozcimen, Muammer; Sakarya, Yasar; Goktas, Sertan; Sakarya, Rabia; Yener, Halil I.; Bukus, Abdulkadir; Demir, Lutfi S.
    Objective: To assess the effects of nepafenac ophthalmic suspension 0.1% for control of pain in patients undergoing pterygium surgery. Methods: This randomized, double-masked placebo-controlled study included 62 adults undergoing pterygium surgery. Patients were randomly assigned to receive nepafenac ophthalmic suspension 0.1% or balanced salt solution placebo. They were asked to assess the level of pain using an 11-point numeric rating scale at 6, 12, 24, 48, and 72 hr after surgery. Patients also were evaluated daily for the progression of corneal epithelial healing until complete closure was observed. Results: Except at 72 hr after surgery, the patients reported significantly less pain in eyes receiving nepafenac than in eyes receiving placebo. There was no statistical difference between the two groups in corneal epithelial healing. Conclusions: Treatment with nepafenac ophthalmic suspension 0.1% significantly reduced postoperative pain compared with placebo after pterygium surgery.
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    The effect of rebreathing and hyperventilation on retinal and choroidal vessels measured by spectral domain optical coherence tomography
    (Taylor & Francis Ltd, 2015) Ozcimen, Muammer; Sakarya, Yasar; Goktas, Sertan; Sakarya, Rabia; Alpfidan, Ismail; Yener, Halil I.; Demir, Lutfi S.
    Objective: The purpose of this study was to examine the vasoreactivity in retina and choroid of the healthy eyes in response to experimentally altered partial arterial pressure of carbon dioxide (PaCO2) using a non-invasive technique, spectral domain optical coherence tomography (SD-OCT). Materials and methods: The study included non-smoking participants between 18 and 35 years of age, having visual acuity of 20/20 and with no systemic and ocular diseases. At baseline, the participants breathed room air (normocapnia). Hypocapnia was created with the help of hyperventilation; for this, the participants were instructed to draw deep and quick breaths, resulting one breathing cycle per 2 s. To create hypercapnia subjects rebreathed from a 5 l bag at least 3 min. Choroidal thickness and retinal artery diameter were measured at baseline, and hyperventilation and rebreathing conditions by SD-OCT. Results: Twenty eyes of 20 healthy subjects were included in this study. Their mean age was 24.90 +/- 5.32 years. Hyperventilation caused a significant reduction in choroidal thickness, compared with baseline, at all points; whereas rebreathing caused no significant change at all points. The mean diameters of the arteries were 151.80 +/- 7.88 mm, with a significant decline to 148.90 +/- 7.25 mm at hyperventilation condition and a significant increase to 153.50 +/- 7.88 mm at rebreathing condition (p = 0.018, p = 0.043, respectively). Conclusion: This study demonstrated that, SD-OCT was a useful tool in measuring the ocular vascular response under hypercapnia and hypocapnia conditions. These findings may be helpful for further understanding the physiological nature of ocular blood flow and this preliminary study provides a basis for future studies.
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    Ganglion cell complex thickness changes in patients with different states of bipolar disorder
    (Springernature, 2022) Cokunlu, Yusuf; Mirza, Enver; Caliskan, Ali Metehan; Inanli, Ikbal; Cicek, Ismet Esra; Ozcimen, Muammer; Eren, Ibrahim
    Objectives Neuroimaging studies in patients with bipolar disorder have suggested that a neuropathological process may be effective in this disease. Neurodegenerative changes in the retina can be followed by optical coherence tomography, a non-invasive imaging method that allows in vivo visualization of the retinal layers. The aim of this study was to investigate the possible differences in optical coherence tomography parameters during euthymic, manic, and depressive episodes in patients diagnosed with bipolar disorder. Methods A total of 150 patients with bipolar disorder were included in the study, divided into three groups (50 patients in a euthymic state, 50 patients in a manic state, and 50 patients in a depressive state) and compared with 50 healthy controls. Ganglion cell complex thickness was measured with automated macular segmentation software of spectral-domain optical coherence tomography. Results Ganglion cell complex thicknesses were thicker in all quadrants in patient groups than the control group but the differences were significant in perifoveal superior and perifoveal inferior quadrants (p < 0.001, p < 0.001). There were no differences in ganglion cell complex thickness among the patient groups (p > 0.05). Conclusion The evaluation of ganglion cell complex thickness by spectral-domain optical coherence tomography may give a clue for monitoring neurodegenerative changes in patients with bipolar disorder.
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    Peripapillary choroidal thickness in patients with chronic obstructive pulmonary disease
    (Taylor & Francis Ltd, 2016) Ozcimen, Muammer; Sakarya, Yasar; Kurtipek, Ercan; Bekci, Taha T.; Goktas, Sertan; Sakarya, Rabia; Yener, Halil I.
    Objective: To evaluate the peripapillary choroidal thickness of patients with chronic obstructive pulmonary disease (COPD) via enhanced depth imaging optical coherence tomography (EDI-OCT).Materials and methods: A total of 80 patients with COPD (80 eyes) and 50 control subjects (50 eyes) were enrolled. Choroidal scans and the retinal nerve fiber layer (RNFL) thickness were obtained for all eyes using OCT.Results: The average peripapillary choroidal thickness measurements of the COPD group (147.5853.53m) were lower than the control group (160.84 +/- 44.73m) (p=0.068). Inferior segment thicknesses were significantly thinner than the other segments (p<0.05). Subfoveal choroidal thickness and RNFL thickness measurements of the COPD group were also lower than those of the control group (p=0.111).Conclusion: Hypoxia in COPD seems to affect the choroidal thickness. Thinning of the choroid may be attributed to increased vascular resistance and reduced blood flow in patients with COPD. The possible effects of the disease to the eye may be clarified through the role of the choroidal vasculature in the blood supply of the anterior optic nerve head.