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Dive into the research topics where Imren Akkoyun is active.

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Featured researches published by Imren Akkoyun.


Acta Ophthalmologica | 2012

Structural consequences after intravitreal bevacizumab injection without increasing apoptotic cell death in a retinopathy of prematurity mouse model

Imren Akkoyun; Gulten Karabay; Nihan Haberal; Attila Dagdeviren; Gürsel Yilmaz; Sibel Oto; Leyla Erkanli; Yonca A. Akova

Purpose:  To evaluate the effect of different bevacizumab concentrations on retinal endothelial cell proliferation, retinal structures and apoptotic activity after intravitreal injection in a retinopathy of prematurity (ROP) mouse model.


Ocular Immunology and Inflammation | 2014

Choroidal Thickness in Ocular Sarcoidosis during Quiescent Phase Using Enhanced Depth Imaging Optical Coherence Tomography

Sirel Gür Güngör; Imren Akkoyun; Nihan Haberal Reyhan; Nilufer Yesilirmak; Gürsel Yilmaz

Abstract Purpose: To evaluate the choroidal thickness in patients with ocular sarcoidosis during quiescent phase using enhanced depth imaging optical coherence tomography (EDI-OCT) and comparing it with normal subjects. Method: Eighteen eyes of 9 patients with ocular sarcoidosis (8 women, 1 man, mean age: 59.12 ± 18.49 years) were enrolled in this study. Their subfoveal choroidal thickness was measured using EDI-OCT in the quiescent phase of uveitis, and compared with the age-, sex-, and spherical equivalent-matched normal subjects (6 women, 3 men, mean age: 59.6 ± 14.22 years). Results: The mean subfoveal choroidal thickness was 281.76 ± 88.1 µm in patients with sarcoidosis and 342.32 ± 71.02 µm in controls. Significant differences were found at points between nasal 1500 µm and temporal 1000 µm to the fovea between patients and control group (p = 0.002, at fovea). Conclusions: Patients with ocular sarcoidosis had thinner choroids in the quiescent phases when compared to normal subjects.


European Journal of Ophthalmology | 2013

Anterior segment complications after phacovitrectomy in diabetic and nondiabetic patients

Eylem Yaman Pinarci; Sezin Akça Bayar; Selcuk Sizmaz; Nilufer Yesilirmak; Imren Akkoyun; Gürsel Yilmaz

Purpose. To evaluate early and late postoperative anterior segment complications of phacovitrectomy and foldable intraocular lens (IOL) implantation in eyes with cataract and coexisting vitreoretinal disease in diabetic and nondiabetic patients. Setting. Department of Ophthalmology, Baskent University Hospital, Ankara, Turkey. Methods. The records of 189 consecutive patients with cataract and posterior segment pathology necessitating phacovitrectomy were retrospectively analyzed. Patient profile, indications for surgery, preoperative findings, intraoperative and postoperative course, and postoperative outcome were evaluated. Phacoemulsification was performed through a clear corneal incision with IOL implantation prior to 23-G pars plana vitrectomy. Results. There were 97 (51.3%) diabetic and 92 (48.6%) nondiabetic patients. The most common indications for surgery were vitreous hemorrhage (57; 58.7%), tractional detachment (35; 36%), and premacular hemorrhage (5; 5.1%) in diabetic patients, and rhegmatogenous retinal detachment (40; 43.4%), macular hole (22; 23.9%), epiretinal membrane (20; 21.7%), and vitreomacular traction (10; 10.8%) in nondiabetic patients. Early (within 4 weeks) postoperative complications included elevation of intraocular pressure, fibrinous uveitis, corneal edema, and development of posterior synechia. Long-term (after 4 weeks) complications included migration of silicone oil into the anterior chamber, posterior capsule opacification, and decentered IOL. The ratio of fibrinous uveitis, posterior synechia, and posterior capsule opacification was found higher in the diabetic group (all p<0.05). Conclusions. Combined vitreoretinal surgery and phacoemulsification is safe and effective in treating vitreoretinal abnormalities coexisting with cataract in diabetic and nondiabetic patients. Diabetic patients should be monitored more carefully for fibrinous uveitis and posterior synechia in the early postoperative period and for posterior capsular opacification in the late postoperative period.


Ophthalmologe | 2013

Aderhautdicke nach Buckelchirurgie bei Makula-off-rhegmatogener Ablatio retinae

Imren Akkoyun; Eylem Yaman Pinarci; Nilufer Yesilirmak; Gürsel Yilmaz

BACKGROUND Enhanced depth imaging (EDI) optical coherence tomography (OCT) provides high-definition cross-sectional images of the choroid. Information on alterations in choroidal thickness (CT) after scleral buckling surgery (SBS) is rare. PATIENTS AND METHODS The medical charts of 122 patients (122 eyes) who underwent SBS for macula-off rhegmatogenous retinal detachment (RRD) were retrospectively analyzed. Patients with a follow-up ≥ 6 months were included. Postoperative EDI-OCT images concerning CT were evaluated 1 week, 1 month and 6 months postoperatively in 4 groups: group 1 cerclage + cryopexy (n = 39 eyes), group 2 cerclage + cryopexy + sponge (n = 28 eyes), group 3 SBS + subretinal fluid drainage (SRD) (n = 25 eyes) and group 4 SBS + sponge + SRD (n = 30 eyes). Subfoveal CT was compared between the groups and with the non-operated fellow eye. RESULTS Subfoveal CT in groups 1, 2, 3 and 4 was thicker 1 week postoperatively. There were no significant differences between the groups or when comparing the operated eye with the fellow eye 1 and 6 months postoperatively. CONCLUSION There were no differences in subfoveal CT 1 and 6 months after SBS between the eye with macula-off RRD and the fellow eye. The use of a sponge or SRD induced no differences concerning subfoveal CT.


Ocular Immunology and Inflammation | 2012

Laser Photocoagulation in Intermediate Uveitis Associated with Retinoschisis

Selcuk Sizmaz; Sirel Gür Güngör; Sezin Akça Bayar; Gürsel Yilmaz; Imren Akkoyun

Purpose: To describe cases of pars planitis associated with retinoschisis, in which laser photocoagulation was carried out. Methods: Retrospective review. Results: Three pars planitis cases were associated with retinoschisis and underwent laser photocoagulation. All cases were idiopathic. Retinoschisis was located in the inferior retinal quadrants in all cases and all of them were in bullous formation. None of the cases developed retinal detachment. Conclusion: As well as posterior vitreous detachment, or peripheral retinal tears, retinoschisis may accompany pars planitis. Laser photocoagulation of the pars plana is effective in these cases both as a treatment and to prevent sight-threatening complications like retinal detachment.


International Journal of Ophthalmology | 2015

Comparison of intravitreal bevacizumab and triamcinolone acetonide theraphies for diffuse diabetic macular edema.

Sibel Aksoy; Gürsel Yilmaz; Imren Akkoyun; Ayşe Canan Yazıcı

AIM To compare therapeutic effects of intravitreal triamcinolone acetonide (IVTA) versus intravitreal bevacizumab (IVB) injections for bilateral diffuse diabetic macular edema (DDME). METHODS Forty eyes of 20 patients with bilateral DDME participated in this study. For each patient, 4 mg/0.1 mL IVTA was injected to one eye and 2.5 mg/0.1 mL IVB was injected to the other eye. The effects of injection for diabetic macular edema (DME) were evaluated using best-corrected visual acuity (BCVA), central macular thickness (CMT) by optical coherence tomography (OCT) and intraocular pressure (IOP) by applanation tonometer. Patients underwent eye examinations, including BCVA, CMT, and IOP at pre-injection, 1, 4, 8, 12 and 24wk after injection. During the follow-up, second injections were performed to eyes which have CMT greater than 400 µm at 12wk for salvage therapy. RESULTS BCVA (logarithm of the minimum angle of resolution) at pre-injection, 1, 4, 8, 12 and 24wk after injection was 0.71±0.19, 0.62±0.23, 0.63±0.12, 0.63±0.13, 0.63±0.14 and 0.61±0.24 in the IVTA group and 0.68±0.25, 0.61±0.22, 0.60±0.24, 0.62±0.25, 0.65±0.26 and 0.59±0.25 in the IVB group, respectively. CMT (µm) at pre-injection, 1, 4, 8, 12 and 24wk after injection was 544±125, 383±96, 335±87, 323±87, 333±92, 335±61 in the IVTA group and 514±100, 431±86, 428±107, 442±106, 478±112, 430±88 in the IVB group respectively. Reduction ratios of mean CMT were 29% at 1wk, 38% at 4wk, 40% at 8wk, 38% at 12wk, and 38% at 24wk in the IVTA group. Second IVTA injections were performed to the 6 eyes (30%) at 12wk. Reduction ratios of mean CMT were 16% at 1wk, 17% at 4wk, 14% at 8wk, 7% at 12wk, and 16% at 24wk in the IVB group. Second IVB injections were performed to the 15 eyes (75%) at 12wk. CONCLUSION This study showed earlier and more frequent macular edema recurrences in the eyes treated with bevacizumab compared with the ones treated with triamcinolone acetonide. Triamcinolone acetonide was found to provide more efficient and long-standing effect in terms of reducing CMT compared with the bevacizumab.


Ophthalmologe | 2014

[Choroidal thickness after scleral buckling surgery in macula-off rhegmatogenous retinal detachment].

Imren Akkoyun; Eylem Yaman Pinarci; Nilufer Yesilirmak; Gürsel Yilmaz

BACKGROUND Enhanced depth imaging (EDI) optical coherence tomography (OCT) provides high-definition cross-sectional images of the choroid. Information on alterations in choroidal thickness (CT) after scleral buckling surgery (SBS) is rare. PATIENTS AND METHODS The medical charts of 122 patients (122 eyes) who underwent SBS for macula-off rhegmatogenous retinal detachment (RRD) were retrospectively analyzed. Patients with a follow-up ≥ 6 months were included. Postoperative EDI-OCT images concerning CT were evaluated 1 week, 1 month and 6 months postoperatively in 4 groups: group 1 cerclage + cryopexy (n = 39 eyes), group 2 cerclage + cryopexy + sponge (n = 28 eyes), group 3 SBS + subretinal fluid drainage (SRD) (n = 25 eyes) and group 4 SBS + sponge + SRD (n = 30 eyes). Subfoveal CT was compared between the groups and with the non-operated fellow eye. RESULTS Subfoveal CT in groups 1, 2, 3 and 4 was thicker 1 week postoperatively. There were no significant differences between the groups or when comparing the operated eye with the fellow eye 1 and 6 months postoperatively. CONCLUSION There were no differences in subfoveal CT 1 and 6 months after SBS between the eye with macula-off RRD and the fellow eye. The use of a sponge or SRD induced no differences concerning subfoveal CT.


Türk Oftalmoloji Dergisi | 2018

Bilateral Asymmetric Rhegmatogenous Retinal Detachment in a Patient with Stickler Syndrome

Caner Öztürk; Almila Sarıgül Sezenöz; Gürsel Yilmaz; Imren Akkoyun

Here we present the long-term anatomical and visual outcomes of bilateral asymmetric rhegmatogenous retinal detachment repair in a patient with Stickler syndrome. A 17-year-old girl presented with decreased visual acuity in both eyes for more than one year. Her best-corrected visual acuity (BCVA) was 0.1 in the right eye and 0.05 in the left eye. Slit-lamp anterior segment examination revealed subcapsular cataract in both eyes. Fundus examination showed bilateral rhegmatogenous retinal detachment, chronic retinal detachment accompanied by multiple retinal holes, tears and membranous fibrillary vitreous in the peripheral retina. Grade C2 proliferative vitreoretinopathy was observed in the left eye. Scleral buckling surgery was performed initially for both eyes. After the primary surgical procedure, retinal reattachment was achieved in the right eye and the left eye underwent phacoemulsification, intraocular lens implantation, pars plana vitrectomy (PPV), and silicone oil injection. After these surgical procedures retinal reattachment was achieved in the left eye. Silicone oil removal was performed six months after PPV surgery. After surgical treatment, BCVA was 0.6 in the right eye at the end of the 3.5-year follow-up period. After silicone oil removal, BCVA reached 0.2 in the left eye after 36 months of follow-up and retinal reattachment was achieved in both eyes. Scleral buckling surgery and PPV are effective and confidential methods for the treatment of chronic retinal detachment cases in Stickler syndrome.


Saudi Journal of Ophthalmology | 2018

A diagnostic dilemma in a patient with delayed onset endophthalmitis

Zeynep Eylül Ercan; Imren Akkoyun; Sirel Gür Güngör; Gürsel Yilmaz

We report a case of nonpainful uveitis nine months after an uncomplicated phacoemulsification cataract surgery. Chronic postoperative endophthalmitis was suspected. Diagnostic vitrectomy and partial capsular bag removal was performed, but the specimens cultured in microbiology laboratory showed no pathogens. Systemic workup came positive for skin Tuberculosis test, and presumed intraocular tuberculosis treatment was started accordingly. Inflammation persisted, so a repeat vitrectomy was performed with removal of the lens implant with the capsule, and this time bedside culture inoculation was performed in operating room, revealing Pseudomonas infection. Delayed-onset postoperative endophthalmitis typically progresses slowly and therefore can be confused with uveitis and treated with steroid and immunosuppressant treatment regimes. Our case confirms both the value of immediate bacterial inoculation and the necessity of aggressive surgical treatment in chronic postoperative endophthalmitis cases.


Cephalalgia | 2018

Relationship between white matter hyperintensities and retinal nerve fiber layer, choroid, and ganglion cell layer thickness in migraine patients:

Ilkin Iyigundogdu; Eda Derle; Leyla Asena; Feride Kural; Seda Kibaroglu; Ruhsen Öcal; Imren Akkoyun; Ufuk Can

Aim To compare the relationship between white matter hyperintensities (WMH) on brain magnetic resonance imaging and retinal nerve fiber layer (RNFL), choroid, and ganglion cell layer (GCL) thicknesses in migraine patients and healthy subjects. We also assessed the role of cerebral hypoperfusion in the formation of these WMH lesions. Methods We enrolled 35 migraine patients without WMH, 37 migraine patients with WMH, and 37 healthy control subjects examined in the Neurology outpatient clinic of our tertiary center from May to December 2015. RFNL, choroid, and GCL thicknesses were measured by optic coherence tomography. Results There were no differences in the RFNL, choroid, or GCL thicknesses between migraine patients with and without WMH (p > 0.05). Choroid layer thicknesses were significantly lower in migraine patients compared to control subjects (p < 0.05), while there were no differences in RFNL and GCL thicknesses (p > 0.05). Conclusions The ‘only cerebral hypoperfusion’ theory was insufficient to explain the pathophysiology of WMH lesions in migraine patients. In addition, the thinning of the choroid thicknesses in migraine patients suggests a potential causative role for cerebral hypoperfusion and decreased perfusion pressure of the choroid layer.

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