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Featured researches published by Uzeyir Erdem.


Ophthalmology | 2010

Safety and Effectiveness of Interferon Alpha-2a in Treatment of Patients with Behçet's Uveitis Refractory to Conventional Treatments

Gungor Sobaci; Uzeyir Erdem; A.Hakan Durukan; Cuneyt Erdurman; Atilla Bayer; Serkan Köksal; Suat Karagül; M.Zeki Bayraktar

PURPOSE To evaluate the intermediate-term safety and effectiveness of interferon alpha-2a (IFNalpha2a) in patients with Behçets uveitis (BU) refractory to corticosteroids and immunosuppressive agents. DESIGN Open, nonrandomized, uncontrolled, interventional, prospective study. PARTICIPANTS Fifty-three patients (106 eyes) with active, vision-threatening BU who failed to respond to conventional treatments. INTERVENTION In 53 patients, acute inflammation was suppressed with effective prednisolone dosage (1-2 mg/kg/day, tapered to 10 mg within 4-6 weeks). The patients were treated with IFNalpha2a 4.5 million international units (MIU) 3 times per week for the first 3 months followed by IFNalpha2a 3 MIU 3 times per week for the next 3 months. Observation or other treatment methods were performed according to the decision tree developed for this study. MAIN OUTCOME MEASURES Remission and complete response (primary outcome measures), frequency of uveitis attacks, visual acuity (VA), and adverse effects (secondary outcome measures). RESULTS During 2 years of follow-up (median 65 months, range 12-130 months), compliance with the therapy was excellent. At the end of 1-year follow-up, treatment response was obtained in 45 of 53 patients (84.9%). The mean attack rate of 3.6+/-1.1 per year (range, 2-8) decreased to 0.56+/-0.75 (range, 0-4) per year (P=0.001). Visual acuity improved (> or = 0.2 logarithm of the minimum angle of resolution units from initial VA) in 30 eyes (28.3%) and worsened in 12 eyes (11.3%). Five patients (9.4%) did not respond to the initial treatment, and 3 patients (5.6%) developed severe adverse effects, including psoriasis, epileptic seizure, and extreme tiredness. Fifteen patients (28.3%) were off treatment for all the medications and disease free for 28+/-13.1 months (range, 12-50 months). CONCLUSIONS These results suggest that IFNalpha2a may be a valuable treatment option in BU that is refractory to corticosteroids and conventional immunosuppressive agents. The possible role of IFNalpha2a as a first-line agent in BU should be validated in randomized controlled clinical trials against newly described biologic agents. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.


Ophthalmology | 2008

Evaluation of Internal Refraction with the Optical Path Difference Scan

Orkun Muftuoglu; Uzeyir Erdem

PURPOSE To evaluate internal refraction and its relation to other optical properties of the eye across a large range of refractive errors, which can provide useful information for the assessment and design of intraocular lenses and corneal ablation patterns. DESIGN Cohort study. PARTICIPANTS Three hundred ninety-four eyes of 197 healthy subjects with a mean age of 27+/-7 years (range, 18-42). METHODS All eyes underwent optical path difference scans to evaluate corneal topography, whole and internal ocular refraction (determined by the subtraction of corneal refraction from whole ocular refraction), and total and higher-order aberrations (HOAs) were assessed. After the conversion of any spherocylindrical refractive errors to vectorial data (sphere equivalent, blurring strength; cylinder, J(0) [power of Jackson cross cylinder at 90 degrees and 180 degrees] and J45 [power of Jackson cross cylinder at 45 degrees and 135 degrees]), the distribution of internal refraction among refraction groups (high myopes, low to moderate myopes, hyperopes, mixed astigmats, and emmetropes) and relationships between internal refraction, corneal refraction, and wavefront aberrations were analyzed. The compensation relation and its rate between corneal and internal astigmatism was assessed by the compensation factor (CF). MAIN OUTCOME MEASURES Whole ocular power and astigmatism, corneal power and astigmatism, internal power and astigmatism, CF for astigmatic data, location of the highest internal refraction zone, and wavefront aberrations. RESULTS The highest refraction zone was mostly (90%) located in the center in myopes, whereas it was located at the nasal side (71%) in hyperopes. There was a significant correlation between whole ocular and internal powers (P<0.01), but no correlation was observed between corneal and internal powers (P>0.05). Internal astigmatism was mostly against the rule. The mean CF J(0) was 0.63+/-3.78 and CF J(45) was 0.57+/-2.47. The magnitude of the internal astigmatism under the 3-mm zone was correlated with the magnitude of corneal astigmatism (P<0.05). The distribution of astigmatic CF differed among refraction groups. There were significant correlations between internal power and spherical aberration (P<0.05) and internal cylinder under the 5-mm zone and HOAs (P<0.001). CONCLUSION There is a remarkable tilt in internal refraction in hyperopes. Although there is a tendency of undercompensation of the corneal astigmatism by internal astigmatism in the entire group of eyes, the compensation differs among refraction groups.


Journal of Refractive Surgery | 2007

Changes in pupil size and centroid shift in eyes with uncomplicated in-the-bag IOL implantation.

Gungor Sobaci; Uzeyir Erdem; Orkun Muftuoglu

PURPOSE To determine changes in entrance pupil size and pupil center shift under low mesopic and photopic conditions of illumination in eyes with in-the-bag intraocular lens (IOL) implantation. METHODS Entrance pupil size and pupil center shift were measured under low mesopic (0.06 lux) and photopic (60 lux) conditions of illumination in 55 patients with unilateral pseudophakia (study group) and 55 age- and sex-matched patients with bilateral cataracts (control group) using the NIDEK OPD-Scan. Pseudophakic eyes had an uncomplicated intraoperative and postoperative course and best spectacle-corrected visual acuity of 20/20. Cataractous eyes had no additional ocular or systemic problems affecting the pupil. Both groups were analyzed with respect to pupil size and shift in both conditions of illumination. RESULTS Mean patient age was 64.2 +/- 6.8 and 63.6 +/- 4.3 years in the study and control groups, respectively (P = .45). In the study group, differences in pupil size under low mesopic (5.12 +/- 1.02 and 5.13 +/- 0.96 mm for pseudophakic and phakic eyes, respectively) and photopic (3.44 +/- 0.39 and 3.45 +/- 0.39 mm for pseudophakic and phakic eyes, respectively) conditions of illumination were not statistically significant (P = 1.00 and P = .95 for pseudophakic and phakic eyes, respectively). Differences in pupil shift between pseudophakic (0.11 +/- 0.08 mm) and phakic (0.12 +/- 0.10 mm) eyes were not statistically significant (P = .83) in the study group. In the control group, differences in pupil size under low mesopic (P = .59) and photopic conditions of illumination (P = .60) in the right and left eyes as well as pupil shift (P = .71) were not statistically significant. CONCLUSIONS Uncomplicated in-the-bag IOL implantation has no influence on pupil size and shift.


Cornea | 2011

Comparison of Oculus Pentacam and Stratus optical coherence tomography for measurement of central corneal thickness.

Osman Melih Ceylan; Adem Türk; Cuneyt Erdurman; Tarkan Mumcuoglu; Uzeyir Erdem; Gokcen Gokce; Selim Dagli

Purpose: Measurement of central corneal thickness (CCT) plays an essential role in the diagnosis and treatment of many ocular diseases. In this study, we aimed to compare the CCT measurements obtained using the Scheimpflug system (Pentacam; Oculus, Inc) with a retinal optical coherence tomography device (Stratus OCT; Carl Zeiss Meditec, Inc) to examine healthy corneas. Methods: CCT measurements of 80 eyes belonging to 40 male patients (mean age: 24.48 ± 6.01 years) were evaluated with the Pentacam and the Stratus OCT. The relationship between the CCT values obtained with these 2 devices was examined with a Pearson correlation analysis, a paired t test, and a Bland-Altman analysis. Results: The average CCT value obtained with Pentacam was 546.11 ± 34.15 μm and that obtained with Stratus OCT was 567.76 ± 35.02 μm. Although the average difference between the devices was 21.65 ± 8.59 μm (P < 0.0001), the measurements obtained with both devices were significantly correlated (r = 0.969, P < 0.0001). In Bland-Altman analysis, there was a high consistency between measurements obtained with either Pentacam or Stratus OCT devices. Conclusions: Corneal thickness measurements differ depending on the device used. Corneal thicknesses that have been calculated with Pentacam were lower than the values obtained with Stratus OCT. Both devices used for CCT measurement are easily applied, noninvasive, and effective. However, the devices are not interchangeable. Stratus OCT is not optimal for CCT measurement because of the important limitations of using manual measurements, but it can be used if other measurement devices designed for the purpose are not available.


Indian Journal of Ophthalmology | 2013

Color vision versus pattern visual evoked potentials in the assessment of subclinical optic pathway involvement in multiple sclerosis.

Fatih C. Gundogan; Ahmet Tas; Oguzhan Oz; Uzeyir Erdem; Gungor Sobaci

Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP) is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM) 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P100 amplitude, P100 latency in PVEP and total error scores (TES) in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7) and 4.1 ± 4.4 years. MS group showed significantly delayed P100 latency for both checks (P < 0.001). Similarly, MS patients had significantly increased total error scores (TES) in FM-100 Hue (P < 0.001). The correlations between TESs and PVEP amplitudes / latencies were insignificant for both checks (P > 0.05 for all). 14 MS patients (70%) had an increased TESs in FM-100 Hue, 11 (55%) MS patients had delayed P100 latency and 9 (45%) had reduced P100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P100 latency, and 0.173 for P100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.


Clinical and Experimental Ophthalmology | 2007

In vivo confocal microscopy findings in a patient with posterior amorphous corneal dystrophy

Uzeyir Erdem; Orkun Muftuoglu; Volkan Hurmeric

A 21‐year‐old man, with bilateral posterior amorphous corneal dystrophy, was studied by biomicroscopy, corneal topography and in vivo confocal microscopy. The best‐corrected visual acuity was 6/21 in the right eye and 6/6.9 in the left eye. Biomicroscopy revealed bilateral, asymmetric, sheet‐like opacification at the deep posterior stromal layer. The corneal topography displayed asymmetric against‐the‐rule astigmatism in the right eye and prominent steepening at the inferior paracentral cornea in both eyes. In vivo confocal microscopy of the corneas demonstrated microfolds and hyper‐reflective layer at the posterior stroma just adjacent to the endothelial layer. The epithelium, Bowman’s membrane, anterior stroma and the endothelial layer were normal. In vivo confocal microscopy is useful in evaluating the corneal dystrophies.


Documenta Ophthalmologica | 2006

The acute effect of cigarette smoking on pattern visual evoked potentials

Ali Hakan Durukan; Fatih C. Gundogan; Uzeyir Erdem; Selim Kilic; Gungor Sobaci; M.Zeki Bayraktar

Reports of tobacco-induced electrocortical activation and decrements in ocular blood flow in the acute faze indicated that this effect is mediated via nicotin’s action or neuronal systems. In this study, pattern visual evoked potentials were investigated in a group of male smokers (22 right eyes of 22 subjects) in separate real smoking and sham smoking sessions. On each session, pattern visual evoked potentials were recorded before smoking, immediately after smoking, and five minutes after smoking. Latency and amplitude values for P100 peaks were assessed and analyzed in each smoking condition for both real smoking and sham smoking sessions. Real smoking significantly decreased P100 latency values (p value related to difference between pre-smoking and immediately after smoking conditions is 0.009) and increased P100 amplitude values (p value related to difference between pre-smoking and fifth minute after smoking is 0.039). Statistically no significant difference was observed in sham smoking sessions. Our results are consistent with smoking-induced stimulant effects on pattern visual evoked potentials.


European Journal of Ophthalmology | 2009

Two-site phacotrabeculectomy versus bimanual microincision cataract surgery combined with trabeculectomy.

Atilla Bayer; Uzeyir Erdem; Tarkan Mumcuoglu; Akyol M

Purpose To compare the results of two-site phacotrabeculectomy with microincision cataract surgery (MICS) and trabeculectomy. Methods Fifty-eight eyes with coexisting cataract and glaucoma were randomly assigned to have a trabeculectomy in a superior quadrant combined with phacoemulsification and intraocular lens (IOL) implantation through temporal clear corneal incision (two-site phacotrabeculectomy group), or a trabeculectomy in a superior quadrant combined with MICS followed by IOL implantation from the trabeculectomy incision (MICS + trabeculectomy group). The main outcome measures were preoperative and postoperative intraocular pressure (IOP), number of glaucoma medications, best-corrected visual acuity (BCVA), and complications. Follow-up was period was 12 months. Results Twenty-eight two-site phacotrabeculectomies and 30 MICS + trabeculectomies were performed. Mean age of the subjects was 67.4 years. Mean preoperative IOP was 24.6±5.7 mmHg in the two-site phacotrabeculectomy group and 23.7±5.5 mmHg in the MICS + trabeculectomy group (p=0.52). At 12 months postoperatively mean IOP was 14.5±3.0 and 14.3±3.4 mmHg in two-site phacotrabeculectomy and MICS + trabeculectomy groups, respectively (p=0.8). Preoperative and postoperative glaucoma medication numbers were similar and mean number of glaucoma medications decreased in both groups after the surgery (p<0.05). BCVA improved in both groups. Twenty-six of 28 eyes (92%) in the two-site + trabeculectomy group and 27 of 30 (90%) in the MICS + trabeculectomy group had clinically apparent filtering blebs at 12 months (p=0.71). Postoperative complications were comparable. Conclusions MICS + trabeculectomy provided 1 year IOP control comparable to that with two-site phacotrabeculectomy with similar amount of complications and similar final BCVA.


Journal of Ophthalmology | 2015

Acute effect of cigarette smoking on pupil size and ocular aberrations: a pre- and postsmoking study.

Uzeyir Erdem; Fatih C. Gundogan; Umut Asli Dinc; Umit Yolcu; Abdullah Ilhan

Aim. To evaluate the acute effects of cigarette smoking on photopic and mesopic pupil sizes and wavefront aberrations. Methods. Cigarette smoker volunteers were recruited in the study. Photopic and mesopic pupil sizes and total ocular aberrations were measured before smoking and immediately after smoking. All volunteers were asked to smoke a single cigarette containing 1.0 mg nicotine. Pupil sizes and total ocular aberrations were assessed by optical path difference scanning system (OPD-Scan II ARK-10000, NIDEK). Only the right eyes were considered for statistical analysis. The changes of pupil size and total ocular aberrations after smoking were tested for significance by Wilcoxon signed ranks test. Results. Mean photopic pupil size decreased from 3.52 ± 0.73 mm to 3.29 ± 0.58 mm (P = 0.001) after smoking. Mean mesopic pupil size was also decreased from 6.42 ± 0.75 mm to 6.14 ± 0.75 mm after smoking (P = 0.001). There was a decrease in all the measured components of aberrations (total wavefront aberration, higher-order aberration, total coma, total trefoil, total tetrafoil, total spherical aberration and total higher-order aberration) after smoking; however the differences were insignificant for all (P > 0.05). Conclusion. Our results indicate that pupil constricts after smoking. On the other hand, smoking does not alter ocular aberrations.


Theoretical Biology and Medical Modelling | 2012

Antiviral activity of salivary microRNAs for ophthalmic herpes zoster

M. Kemal Irmak; Uzeyir Erdem; Ayhan Kubar

Ophthalmic herpes zoster is a common ocular infection caused by the varicella-zoster virus (VZV). Viral mRNA transcripts play a major role in the replicative cycle of the virus and current antiviral agents have little effect in preventing and treating the complications. Therapeutic use of saliva for certain painful ocular diseases such as ophthalmic herpes zoster is a well-known public practice in our region. We thought that antiviral activity of saliva may stem from salivary microvesicles and we aimed to look for molecules with antiviral activity in these vesicles. As a possible candidate for antiviral activity, salivary microvesicles contain at least 20 microRNAs (miRNAs), small noncoding RNAs, which suppress the translation of target mRNAs. miRNAs not only participate in maintenance of normal cell functions, but are also involved in host–virus interactions and limit the replication of certain virus types. Thus, miRNA gene therapy by targeting mRNAs required for VZV survival may find a niche in the treatment of ophthalmic herpes zoster. But, how could salivary microvesicles reach into the corneal cells to demonstrate their antiviral activity. We suggest that human salivary microvesicles can be effective carriers of miRNA for corneal cells, because they contain a molecular machinery for vesicle trafficking and fusion allowing them to be endocytosed by target cells. After binding to the plasma membrane, microvesicles seem to enter into the corneal cells through the clathrin-mediated endocytosis. In the cytosol, human salivary miRNAs base-pair with specific viral mRNAs and inhibit their translation, thus limiting the replication of the virus.

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Gungor Sobaci

Military Medical Academy

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Abdullah Ilhan

Military Medical Academy

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Ahmet Tas

Military Medical Academy

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Umit Yolcu

Military Medical Academy

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Gokcen Gokce

Military Medical Academy

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Atilla Bayer

Military Medical Academy

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Selim Dagli

Military Medical Academy

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