Browsing by Author "Gokmen, Onur"

Now showing 1 - 8 of 8

The Effects of Chronic Smoking on Retinal Vascular Densities and Choroidal Thicknesses Measured by Optical Coherence Tomography Angiography
(Sage Publications Ltd, 2023) Gokmen, Onur; Ozgur, Gokhan
Purpose To examine the effects of chronic smoking on vascular density in superficial and deep retinal vascular plexuses and choroidal thicknesses. Method Superficial and deep vessel densities and choroidal thicknesses of smoking volunteers and healthy non-smoking volunteers were measured with the Topcon DRI OCT-1 Tritron (R) device and compared with each other. Results This study included 108 eyes of 54 smoking volunteers and 108 eyes of 54 healthy volunteers as a control group. The average superficial vascular density index and deep vascular density indexes of smokers were found to be 39.81 +/- 1.5% and 42.53 +/- 1.9%, respectively (P = 0.53), while the non-smoking control group was 40.09 +/- 1.3% and 41.57 +/- 1.6%, respectively (P = 0.006). Average choroidal thicknesses were 284.22 +/- 59 in smokers and 270.72 +/- 61 in the control group (P = 0.247). Also, smoking quantity per day x years was found to be significantly negatively correlated with average choroidal thicknesses. (P = 0,011). Discussion In this study, it was determined that chronic smoking increases deep retinal vascular densities on retinal vascular plexus. However, the cumulative effect of smoking was found to be negatively correlated with choroidal thicknesses. Smoking has microvascular effects on vessels such as vasodilatation, vasoconstriction, increased platelet aggregation, endothelial dysfunction. However, studies in the literature are in dispute with the effects of smoking on choroidal and retinal vessels. This study may show that chronic smoking may have different vascular effects on the superficial and deep plexuses and choroidal vessels, as well as different effects from acute use.
In-Vitro Dewetting Properties of Planned Replacement and Daily Disposable Silicone Hydrogel Contact Lenses
(Elsevier, 2021) Havuz, Erol; Gokmen, Onur
Aim: To compare the in-vitro videokeratoscopic surface dewetting properties of new-generation silicone hydrogel (SiH) planned replacement contact lenses (CL) with those of daily disposable CLs. Method: A chrome coated cornea model was used for the in-vitro evaluation of surface dewetting. Pre-lens and post-lens film layers were formed by instilling a normal preservative-free normal saline solution (PFNs) (0.9 %) before and after the placement of the CL on the model cornea. The tests were carried out on fanfilcon A, lotrafilcon B, samfilcon A, and senofilcon A lenses, as well as such daily disposable lenses as delefilcon, nesofilcon A and senofilcon one day. Using videokeratoscopic methods, images were obtained at 30-second intervals up to 180 s in the lens and control groups and were analyzed by the ImajeJ (R) program. Results: The mean measured area of the keratoscopic rings was largest in the fanfilcon group (67.56 mm(2)), followed by 61.53 mm(2) in the lotrafilcon A group and 64.60 mm(2) in the samfilcon group, while the smallest area was measured in the senofilcon A group, at 56.90 mm(2). The area was measured as 64.33, 63.09 and 68.39 mm(2) for the delefilcon, nesofilcon and Senofilcon one day CLs, respectively. The dewetting patterns and properties differed in the CL groups (p < 0.05), while no significant differences were found between the measured areas of the planned replacement and daily disposable CL groups (p > 0.05). Discussion: Videokeratoscopy using in-vitro cornea models has been identified as a reproducible and reliable method for the analysis of the surface dewetting of CLs. The dewetting characteristics of CL groups have been found to differ from each other, despite all being produced from SiH materials. The surface wetting coating has been shown to affect CL dewetting performance.
Effects of Covid-19 Infection on Retinal Vascular Density and Choroidal Thickness Measured by Optical Coherence Tomography Angiography
(Elsevier, 2023) Gokmen, Onur; Ozgur, Gokhan
Aim: The present study evaluates the possible effects of COVID-19 on choroid thickness, the Foveal Avascular Zone (FAZ) and retinal vascular indices in the same individuals who had Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) data prior to the COVID-19 pandemic.Methods: The OCT and OCTA images of the same individuals with no known ophthalmic pathology who developed a COVID-19 infection were obtained were retrieved retrospectively from the database and compared with the repeated images of OCT and OCTA images 1-2 months after COVID-19 infection.Results: Eighty eyes of 40 patients (26 female [65%], 14 male [35%]) who had developed a prior Covid-19 infection were included in the study. When comparing the measurements of the same participants before and after Covid-19 infection, no significant difference was detected in the mean average choroidal thicknesses (p=0.998), average superficial (p=0.425) and deep (p=0.333) retinal vascular densities, and superficial (p=0.991) and deep (p=0.075) FAZ measurements.Conclusions: No significant effect of COVID-19 on choroid thickness, FAZ or retinal vascular densities was noted in the present study, although there are some studies in literature with equivocal results.
Diyabetik Maküler Ödemde İntravitreal Ranibizumab Monoterapisi ve İntravitreal Ranibizumab ve İntravitreal Triamsinolon Kombinasyon Tedavisi Sonuçlarımız
(2021) Gokmen, Onur; Sekeryapan, Berrak; Ozgur, Gokhan
Amaç: Diyabetik maküler ödem (DMÖ) tedavisinde intra-vitreal ranibizumab (IVR) monoterapisi ve IVR+intra-vitreal triamsinolon (IVTA) kombinasyon tedavisinin görme keskinliği (GK) ve santral foveal kalınlık (SFK) üzerindeki etkilerini araştırmak. Gereç ve Yöntemler: Klinik olarak anlamlı DMÖ olan 37 hastanın 52 gözü çalışmaya dahil edildi. Tüm hastalara başlangıçta intra-vitreal yolla 0.5 mg / 0.05 ml ranibizumab uygulandı. 2 ranibizumab enjeksiyonunu takiben yeterli yanıt alınamayan olgulara IVR+IVTA kombinasyon tedavisi uygulandı. Görme keskinliği ve SFK değerleri enjeksiyondan önce ve enjeksiyondan 1, 3 ve 6 ay sonra karşılaştırıldı. Bulgular: Enjeksiyondan önce ortalama görme keskinliği 0.68±0.42 logMAR iken. Birinci ve üçüncü aylarda görme keskinliğinde enjeksiyon öncesi değerlere göre istatistiksel olarak anlamlı bir artış saptandı (p<0.05). Görme keskinliği altıncı ayda da artmasına rağmen, gruplar arasındaki fark istatistiksel olarak anlamlı değildi (p>0.05). Enjeksiyondan önce ortalama SFK değeri 557.4±157.7 μm idi. Enjeksiyon öncesi SFK ile karşılaştırıldığında 1, 3 ve 6. ayların SFK değerlerinde istatistiksel olarak anlamlı bir azalma saptandı (p<0.05). IVR ve IVR+IVTA kombinasyon tedavisi uygulanan hastalar 6 aylık sonuçlarla karşılaştırıldığında, ortalama GK sırasıyla 0.60±0.41 logMar ve 0.58±0.38 logMar olarak bulunmuştur; ortalama SFK değerleri sırasıyla 419.35±205.5 μm ve 487.0±215.5 μm olarak bulundu. İki grup arasında istatistiksel olarak anlamlı bir fark gözlenmedi (p>0.05). Sonuç: IVR+IVTA kombinasyon tedavisi, intra-vitreal ranibizumab monoterapisi ile birlikte dirençli DMÖ olgularında alternatif bir yöntem olabilir.
The Influence of Dead Spaces and the Designs of Injectors on the Amount of Drug Dose in Intra-Vitreal Injection
(Sage Publications Ltd, 2021) Havuz, Erol; Gudul Havuz, Seda; Gokmen, Onur
Aim: To evaluate the dead spaces resulting from different designs of the insulin injectors used for intravitreal injections and the amounts of drug doses. Methods: In the study, five different brands of sterile insulin injectors of 1 mL were used for the test. The weight of the injectors was determined before and after filling the injectors with 0.05 and 0.1 mL distilled water. The weight of the injectors was measured with and without the needle after the water within the injectors had been taken out and weight differences were measured. The difference between the intended amount of fluid to be thrown out and the weight of the fluid remaining in the injector was calculated as percent error. Results: After throwing out 0.05 mL distilled water from the injector, weights of the Beybi(R), Traf(R), Becton Dickinson(R), Ayset(R), and Setojet(R) brands of injectors with 30 G needle were detected to increase the mean 0.0220 +/- 0.006 g, 0.0208 +/- 0.008 g, 0.0355 +/- 0.016 g, 0.0219 +/- 0.017 g, and 0.0150 +/- 0.007 g, respectively compared to the weights of the dry injectors. The 0.1 mL injector group was found to be mean 0.0350 +/- 0.014 g, 0.0264 +/- 0.008 g, 0.0405 +/- 0.015 g, 0.0272 +/- 0.013 g, and 0.0245 +/- 0.014 g, respectively. The maximum increase due to the dead spaces in the injectors was found in the Becton Dickinson(R) injector, both in the 0.05 mL and the 0.1 mL groups (p < 0.000). Conclusion: The injector designs may affect the dose of IVI required to be given. More correct amounts of drugs may be administered via the intra-vitreal route through designs that reduce the dead spaces at the end part of the injector and between the inner wall and the plunger.
Associations Between Body Mass Index and Choroidal Thickness, Superficial and Deep Retinal Vascular Indices, and Foveal Avascular Zone Measured by Octa
(Elsevier, 2023) Ozgur, Gokhan; Gokmen, Onur
Aim: The present study explores the effects of Body Mass Index (BMI) on choroidal thickness, the deep and superficial retinal capillary plexuses, and the foveal avascular zone (FAZ). Methods: The subjects in this prospective study were divided into five groups based on their calculated BMI. Choroidal thickness, superficial and deep retinal capillary plexuses, and FAZ were measured using enhance depth imaging (EDI) and optical coherence tomography angiography (OCTA). The groups were then compared and correlations with BMI were evaluated. Results: The study included 210 eyes of 105 subjects. The comparison of the BMI groups revealed a significant decrease in the mean choroidal thicknesses in the obese groups (p = 0.001), and a significant negative correlation between BMI and mean choroidal thickness (p = 0.02). The results of the analysis of the mean superficial and deep retinal capillary plexuses did not differ between the groups (p = 0.089, p = 0.808 respectively), while the deep FAZ measurements revealed a significant decrease in the obese groups (p = 0.003). Conclusion: Choroidal thickness and deep FAZ are significantly negatively correlated with BMI, suggesting potential choroidal and retinal microvascular effects of obesity.
Covıd-19 Pandemisinin Oftalmologların Klinik Tutum ve Alışkanlıklarına Etkisinin Araştırılması: Bir Anket Çalışması
(2021) Ozgur, Gokhan; Gokmen, Onur; Beyazyıldız, Özlem; Havuz, Erol
Amaç: Koronavirüs hastalığı-2019 [coronavirus disease-2019 (COVID-19)] pandemisi kısa süre içerisinde tüm dünyada hızla yayı- lırken, hastalarla çok yakın temas gerektiren oftalmolojik muayeneler de oftalmologlar açısından hastalık bulaş riskini artırmaktadır. Bu ça- lışmada, oftalmologların kendilerini korumak adına göz polikliniğinde kullandıkları çeşitli kişisel koruyucu kıyafet, ekipmanlar ile pandemi sürecinde hastalara karşı yaklaşım ve tutum değişikliklerinin incelen- mesi hedeflenmiştir. Gereç ve Yöntemler: Türkiye’de pandemi baş- langıcından itibaren 3 aylık dönem içerisinde oftalmologların poliklinikte maske, kıyafet, biyomikroskop nefes kalkanı, koruyucu gözlük, eldiven kullanımı, kontakt lens verme alışkanlıkları, cerrahi uy- gulamalar, hasta sayıları, hastalara karşı tutumları, geçirilmiş COVID- 19 enfeksiyon öyküleri, COVID-19 pozitif hasta temasları ve oftalmoloji dışı aldıkları COVID-19 görevleri hakkında 22 soruluk anket hazırlanarak, Türkiye’de görev yapan ve ulaşılabilen tüm oftal- mologlara gönderilerek, elde edilen veriler analiz edildi. Bulgular: Ça- lışmaya, 112 gönüllü oftalmolog katılmıştır. Katılımcıların tamamı poliklinikte maske kullanırken, %79,6’sı koruyucu kıyafet, %64,5’i yüz koruyucu ekipman, %96,4’ü biyomikroskop nefes kalkanı kullanmakta idi. Katılımcıların %44’ü oftalmoloji dışı COVID-19 görevinde bulu- nurken, %92’sinin kontakt lens verme, %93’ünün ise cerrahi rutini pan- demi sürecinde değişmiştir. Hastalarla olan iletişim, hasta sayıları, muayene süreleri de değişen oranlarda pandemi sürecinden etkilen- miştir. Sonuç: Oftalmologların, kişisel koruyucu ekipman ve kıyafet- ler konusunda tutum ve davranışları değişkenlikler göstermektedir. Pandemi sürecinde birçok oftalmolog, alanları dışında pandemi görev- lerinde bulunmuşlardır ve bu süreç oftalmologların hastalarla olan ile- tişim ve muayene sürelerini, hasta sayılarını, oftalmologların kontakt lens verme ve cerrahi uygulama gibi rutinlerini değişen oranlarda etki- lemiştir.
Safety Profile of Intravitreal Injections in the Injection Cabinet: No Cases of Endophthalmitis Seen After 7238 Injections
(Kare Publ, 2023) Ozgur, Gokhan; Gokmen, Onur
Objectives: The present study evaluates the rate of endophthalmitis in intravitreal injections (IVI) performed in a modular injection cabin that could be easily sited in a closet in an office environment, and the performance tests of the cabin in terms of heating, ventilation, and air conditioning (HVAC). Methods: The injections were given over approximately 18 months in the cabin and the demographics of the patients were screened retrospectively, and the cabin was subjected to HVAC tests. Results: A total of 7,238 injections were performed in the defined period, and no cases of endophthalmitis were encountered (0%). The results of the airflow and flow rate, particle count, pressure difference, decontamination time, light, moisture, and heat tests were all found to be above the standard defined by the International Organization for Standardization (ISO). Conclusion: An injection cabin is a practical modular construction that can be easily sited in any space without the need for special climatization, and provides a sterile and safe environment for IVI.