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Dive into the research topics where Onur Konuk is active.

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Featured researches published by Onur Konuk.


Ophthalmic Plastic and Reconstructive Surgery | 2003

Balanced orbital decompression combined with fat removal in Graves ophthalmopathy: do we really need to remove the third wall?

Mehmet Ünal; Fikret leri; Onur Konuk; Berati Hasanreisoglu

Purpose To compare the reduction of proptosis and the incidence of new-onset diplopia after 3-wall (medial, lateral, and inferior) orbital decompression versus balanced medial and lateral wall decompression combined with orbital fat excision in patients with Graves ophthalmopathy. Methods Three-wall orbital decompression including medial, inferior, and lateral walls was performed in 13 eyes of 7 patients (group 1), and balanced medial and lateral wall decompression combined with fat removal was performed in 18 eyes of 11 patients (group 2). A transnasal endoscopic approach was used for medial wall removal. A lateral canthotomy incision combined with a short upper eyelid incision was used for extended lateral wall removal, and this was combined with an inferior conjunctival fornix incision when floor decompression was performed. Results The mean reduction of proptosis was 6.9±1.6 mm and 6.5±1.3 mm in the first and second groups, respectively; the difference was not statistically significant (P =0.37). After 3-wall decompression, 57.1% of the patients had permanent new-onset diplopia (group 1), whereas none of the patients had permanent postoperative diplopia after balanced medial and lateral wall decompression combined with fat removal (group 2). The difference in permanent new-onset postoperative diplopia between two groups was statistically significant (P <0.001). Conclusions Balanced medial and lateral wall decompression combined with orbital fat removal provides an effective reduction in proptosis and reduces the incidence of postoperative permanent diplopia when compared with 3-wall decompression. This technique may eliminate the need for orbital floor excision.


Journal of Refractive Surgery | 2000

Results of photorefractive keratectomy in keratoconus suspects at 4 years.

Kamil Bilgihan; Sengul Ozdek; Onur Konuk; Fikret Akata; Berati Hasanreisoglu

PURPOSE We studied the long-term results of photorefractive keratectomy (PRK) in keratoconus suspects detected by videokeratography (TMS). METHODS Bilateral inferior corneal steepening was detected in 6 candidates for PRK presenting with moderate myopia or astigmatism. Mean follow-up was 44.5 +/- 4.4 months (range, 38 to 54 mo). Mean spherical equivalent refraction was -5.18 +/- 1.60 D (mean sphere, -4.73 D; mean cyclinder, -0.92 D) which was stable for at least the preceding year. The quantitative measurement of inferior corneal steepening (I-S value) was greater than +1.60 (mean, 1.83 +/- 0.11) in all eyes. An Aesculap Meditec Mel 60 excimer laser was used for the PRK procedures and mean follow-up was 44.5 months. Postoperative pachymetric measurements were also performed in 6 eyes. RESULTS Postoperative uncorrected visual acuity was 20/20 in 8 eyes (66.6%) and 20/32 or better in all eyes with a mean postoperative spherical equivalent refraction of -0.70 +/- 0.74 D (mean sphere, -0.63 D; mean cyclinder, -0.39 D). Five eyes (41.6%) were within +/- 0.50 D spherical equivalent refraction. Inferior steepening was associated with thinning of the inferior cornea which was statistically significantly thinner than the superior thickness (Students t-test, P < .05). There were no wound healing problems or any sign that the excimer laser adversely affected the cornea during follow-up. CONCLUSIONS Photorefractive keratectomy seems to be a safe procedure for reducing or eliminating myopia or astigmatism in keratoconus suspect eyes-most probably forme fruste keratoconus-with a stable refraction, but this may be different in eyes with early keratoconus, known to be a progressive disease.


Ophthalmologica | 2010

Unsuccessful Lacrimal Surgery: Causative Factors and Results of Surgical Management in a Tertiary Referral Center

Onur Konuk; Mine Kurtulmusoglu; Zaure Knatova; Mehmet Ünal

Background: To evaluate possible causative factors of unsuccessful dacryocystorhinostomy (DCR) surgery, and present the surgical technique and results of revision external DCR in a tertiary referral center. Methods: During 2001–2007, 79 patients (59 female, 20 male, 83 revised DCR sites) underwent revision external DCR for the management of recurrent epiphora after unsuccessful DCR surgery. The possible reasons for unsuccessful DCR surgery were noted according to the preoperative nasal endoscopic and perioperative findings, and revision surgery was performed to address these. Results: The mean age was 43.1 ± 12.0 years, and the mean follow-up was 21.4 ± 12.4 months. At presentation, 58 patients had a history of 1 unsuccessful lacrimal surgery, 16 had 2 unsuccessful surgeries, and 5 had 3 unsuccessful surgeries. The most common preoperative endoscopic finding was nasal mucosal fibrosis and synechiae, and the most common causes of unsuccessful DCR surgery were inappropriate size and location of the bony ostium, fibrosis at rhinostomy site, and canalicular obstruction, respectively. Of the 83 revised DCR sites, 79 sites underwent external DCR with silicone intubation, and conjunctival DCR with Jones tube insertion was performed in 4 sites. Success was achieved in 78 sites (93.9%) with the first revision DCR surgery, and in 81 sites (97.6%) with the second revision. Conclusions: Revision DCR has standard concepts in common with primary DCR surgery; however, for a favorable surgical outcome, the revision surgery should address possible causative factors of failure.


Journal of Cataract and Refractive Surgery | 2001

Ascorbic acid levels in human tears after photorefractive keratectomy, transepithelial photorefractive keratectomy, and laser in situ keratomileusis

Ayse Bilgihan; Kamil Bilgihan; Yasin Toklu; Onur Konuk; Özgür Yis; Berati Hasanreisoglu

Purpose: To investigate the level of ascorbic acid in human tear fluid after photorefractive keratectomy (PRK), transepithelial PRK, and laser in situ keratomileusis (LASIK). Setting: Departments of Ophthalmology and Biochemistry, School of Medicine, Gazi University, Ankara, Turkey. Methods: Twenty patients (7 women and 13 men) were included in this study. Traditional PRK with epithelial scraping by a blunt spatula followed by surface ablation (7 eyes), transepithelial PRK (7 eyes), or LASIK (6 eyes) was performed. Tears were collected preoperatively and 1 and 5 days postoperatively. Ascorbic acid levels were measured using 2‐4 dinitrophenylhydrazine. Results: Ascorbic acid levels in the tear fluid were decreased significantly 1 day after PRK, transepithelial PRK, and LASIK (P < .05). On the fifth day, the ascorbic acid levels were significantly lower than preoperatively in all groups. Conclusion: After PRK, transepithelial PRK, and LASIK, the ascorbic acid levels of the tear fluid decreased significantly. Because ascorbic acid is the major scavenger of superoxide radicals in tears, topical ascorbic acid therapy may help eliminate the harmful effect of free radicals from excimer laser surgery.


Ophthalmic Plastic and Reconstructive Surgery | 2004

Outcome of patients with nasolacrimal polyurethane stent implantation: do they keep tearing?

Sertaç Öztürk; Onur Konuk; Erhan T. Ilgit; Mehmet Ünal; Özlem Erdem

Purpose To evaluate the results of nasolacrimal polyurethane stent implantation for the treatment of primary acquired nasolacrimal duct obstruction and the effects of obstructed nasolacrimal stent on subsequent dacryocystorhinostomy (DCR). Methods This study was designed as a nonrandomized, prospective clinical trial. Stent implantation was attempted in 53 obstructed lacrimal drainage systems of 47 patients. Stent placement was performed in a retrograde fashion through the external nare over a guide wire, which was introduced from the upper punctum. Occluded stents were removed either with nasal endoscopy or during DCR. External DCR surgery with silicone intubation was performed in cases with stent failure. Results The mean follow-up period was 23.4 months. The success rate of stent implantation was 60.4%, 37.5%, and 31.2% at 6-, 12-, and 18-month follow-up, respectively. Stent obstruction developed in 33 eyes. Twenty underwent external DCR with silicone intubation. During DCR surgery, varying degrees of chronic inflammatory reaction were detected in the lacrimal sac and nasolacrimal duct. The mean follow-up period after DCR was 10.3 months. Epiphora was relieved with DCR in all but one eye. Conclusions The success rate of nasolacrimal polyurethane stent implantation for the treatment of primary acquired nasolacrimal duct obstruction is low and may induce inflammation and fibrous tissue formation. Although this may cause further difficulties in subsequent lacrimal surgery, epiphora could be relieved with meticulous technique.


British Journal of Ophthalmology | 2015

PREGO (presentation of Graves’ orbitopathy) study: changes in referral patterns to European Group On Graves’ Orbitopathy (EUGOGO) centres over the period from 2000 to 2012

Petros Perros; Miloš Žarković; Claudio Azzolini; Göksun Ayvaz; L Baldeschi; Luigi Bartalena; Antonella Boschi; Claire Bournaud; Thomas Heiberg Brix; Danila Covelli; Slavica Ćirić; Chantal Daumerie; Anja Eckstein; Nicole Fichter; Dagmar Führer; Laszlo Hegedüs; George J. Kahaly; Onur Konuk; Jürg Lareida; John H. Lazarus; Marenza Leo; Lemonia Mathiopoulou; Francesca Menconi; Daniel Morris; Onyebuchi E. Okosieme; Jaques Orgiazzi; Susanne Pitz; Mario Salvi; Cristina Vardanian-Vartin; Wilmar M. Wiersinga

Background/aims The epidemiology of Graves’ orbitopathy (GO) may be changing. The aim of the study was to identify trends in presentation of GO to tertiary centres and initial management over time. Methods Prospective observational study of European Group On Graves’ Orbitopathy (EUGOGO) centres. All new referrals with a diagnosis of GO over a 4-month period in 2012 were included. Clinical and demographic characteristics, referral timelines and initial decisions about management were recorded. The data were compared with a similar EUGOGO survey performed in 2000. Results The demographic characteristics of 269 patients studied in 2012 were similar to those collected in the year 2000, including smoking rates (40.0% vs 40.2%). Mild (60.5% vs 41.2%, p<0.01) and inactive GO (63.2% vs 39.9%, p<0.01) were more prevalent in 2012. The times from diagnosis of thyroid disease to being seen in EUGOGO centres (6 vs 16 months) and from first symptoms of GO (9 vs 16 months) or from diagnosis of GO (6 vs 12 months) to first consultation in EUGOGO centres were shorter in 2012 (p<0.01). The initial management plans for GO were no different except surgical treatments for patients with mild inactive disease were more frequently offered in the 2012 cohort than in 2000 (27.3% vs 17%, p<0.05), and selenium supplements were offered only in the 2012 cohort (21.2% vs 0%, p<0.01). Conclusions These findings suggest that the clinical manifestations of patients with GO may be changing over time in Europe.


Ophthalmic Plastic and Reconstructive Surgery | 2008

Long-term success rate of perforated punctal plugs in the management of acquired punctal stenosis.

Onur Konuk; Berrak Urgancioglu; Mehmet Ünal

Purpose: To give the long-term success rates of punctal dilatation with insertion of perforated punctal plugs (PPP) for the management of acquired punctal stenosis. Methods: A series of 44 eyes of 26 patients who underwent PPP implantation for the management of acquired punctal stenosis were retrospectively evaluated in terms of the severity of acquired punctal stenosis, associated eyelid disorders, implantation technique of PPP, and long-term success rate of PPP for the treatment of epiphora. In all patients, punctal dilation was performed prior to the insertion of plugs. Patients demonstrating moderate or severe horizontal eyelid laxity underwent a lateral tarsal strip procedure before PPP implantation. Complete stenosis of the punctum was treated with the radiofrequency unit before PPP implantation. The plugs were extracted at 2 months in every patient. Results: The mean age of the patients was 63.6 ± 10.5 years. The median interval between the onset of epiphora and PPP implantation was 15 months. There were 14 complete stenoses, 29 partial punctal stenoses, and 1 squamous papilloma involving the inferior punctum causing epiphora. Associated eyelid laxity was detected in 14 of 44 eyes (31.8%), and 8 eyes underwent a lateral tarsal strip procedure before PPP implantation. The mean follow-up time was 19.0 ± 13.4 months. Success was achieved in 37 of 44 eyes (84.1%), with relief of epiphora. Of the 7 eyes with continued epiphora, 3 eyes demonstrated recurrent punctal stenosis and 4 eyes demonstrated mild horizontal eyelid laxity. Conclusions: The long-term success rate of PPP implantation for the treatment of acquired punctal stenosis is satisfactory. Associated eyelid pathologies should be evaluated for their contribution to epiphora and be treated before PPP implantation.


Current Eye Research | 2014

Intraocular Pressure Lowering Effect of Orbital Decompression is Related to Increased Venous Outflow in Graves Orbitopathy

Zafer Onaran; Onur Konuk; Suna Özhan Oktar; Cem Yücel; Mehmet Ünal

Abstract Purpose: To investigate the effects of combined orbital bone and fat decompression on intraocular pressure (IOP) and superior ophthalmic vein blood flow velocity (SOV-BFV), and their association with the clinical features of Graves orbitopathy (GO). Methods: During the 2002–2008 period, 72 eyes of 36 GO cases demonstrating moderate to severe orbitopathy were evaluated according to their clinical features as: cases with or without dysthyroid optic neuropathy (DON), and underwent orbital decompression. A control group comprised 40 eyes of 20 healthy subjects. In both groups, a full ophthalmic examination including IOP and Hertel measurements was performed, and SOV-BFV was analyzed with color Doppler imaging. Examinations were repeated after orbital decompression in GO patients. Results: All the cases demonstrated clinical features of inactive disease. Among the patients 24 of 72 eyes (33.3%) showed clinical features of DON. After surgery, the mean decrease in Hertel values was 6.2 ± 1.8 mm (p = 0.001). The mean decrease in IOP was 3.0 ± 1.7 mmHg (from 17.3 ± 2.7 to 14.3 ± 2.0 mmHg) after orbital decompression where the post-operative values were comparable with the control group (12.9 ± 1.4 mmHg, p = 0.36). The mean increase in SOV-BFV achieved with decompression was 1.2 ± 0.6 cm/s (from 4.8 ± 1.7 to 6.0 ± 1.8 cm/s) and post-operative SOV-BFV values were also comparable with the control group (6.6 ± 1.3 cm/s, p = 0.26). The increase in SOV-BFV in cases with DON did not differ from cases without DON (p = 0.32), however, post-operative SOV-BFV of cases with DON was stil lower than cases without DON (p = 0.035). Conclusions: Combined orbital bone and fat decompression significantly reduced the IOP levels and increased the SOV-BFV in GO. This could be the confirmative finding of prediction that elevated IOP in GO is associated with increased episcleral venous pressure. The post-operative changes in IOP and SOV-BFV show differences regarding the clinical features of disease.


Clinical Dysmorphology | 2007

A novel mutation in TRIM37 is associated with mulibrey nanism in a Turkish boy.

T may Do anc; Berrin Konuk; Nursel Alpan; Onur Konuk; Riikka H. H m l inen; Anna-Elina Lehesjoki; Mustafa Tekin

Mulibrey nanism is a rare autosomal-recessive disorder characterized by prenatal onset severe growth retardation and pericardial constriction associated with abnormalities of muscle, liver, brain and eye. More than 80% of previously reported patients are of Finnish origin in whom a founder mutation in the TRIM37 gene have been described. We report on a 7-year-old Turkish boy who presented with classical phenotypic features of mulibrey nanism. Mutation screening of the TRIM37 gene revealed that the proband had a homozygous two base pair deletion, c.1894_1895delGA, resulting in a frame-shift and a premature termination codon. Our proband is one of the rare examples of mulibrey nanism outside Finland and extends the mutation spectrum in this disorder.


Retina-the Journal of Retinal and Vitreous Diseases | 2006

Ocular ischemic syndrome presenting as central retinal artery occlusion in scleroderma.

Onur Konuk; Ozdek Sc; Onal B; Tiftikçioğlu Y; Gökhan Gürelik; Berati Hasanreisoglu

Ocular ischemic syndrome (OIS) comprises various ocular signs and symptoms due to severe stenosis of the ipsilateral carotid arterial system. The obstruction can be within the common carotid or internal carotid artery, and the affected vessel is totally occluded in one half of the cases.1 Most central retinal artery occlusions (CRAOs) are caused by thrombosis at or just proximal to the lamina cribrosa, and the patients have sudden painless visual loss with cloudy retinal swelling and a cherry red spot in the fovea. However, obstructions more proximal to the lamina cribrosa, such as in the ophthalmic artery or internal carotid artery, may have similar clinical features that may be difficult to distinguish from CRAO.2 We describe a patient with scleroderma who developed total internal carotid artery occlusion simulating clinical features of CRAO.

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Petros Perros

Royal Victoria Infirmary

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