Araştırma Çıktıları

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Author: search.filters.author.Karabas, Levent

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    Correlation of Visual Recovery and Increased Ellipsoid Zone Reflectivity After Successful Macular Hole Surgery
    (TURKISH OPHTHALMOLOGICAL SOC, 2020-01-01) Tugan, Busra Yilmaz; Karabas, Levent; Yenihayat, Fatih; Subasi, Sevgi; Kesim, Enes; Ozkan, Berna
    Objectives: To assess changes in reflectivity of the retinal pigment epithelium (RPE), ellipsoid zone (EZ), and external limiting membrane (ELM) on spectral domain-optical coherence tomography (SD-OCT) images and the effects of reflectivity changes on visual acuity improvement after vitrectomy in macular hole patients. Materials and Methods: Twenty-four eyes of 24 patients with idiopathic full-thickness macular hole closed after vitrectomy were retrospectively reviewed. The ``plot profile{''} function of the medical imaging software was used by a single masked physician to analyze RPE, EZ, and ELM reflectivity on OCT images at postoperative 1 month and 12 months. Results: Absolute and relative EZ reflectivity showed highly significant increases at postoperative 12 months compared to 1 month (p<0.001 and p<0.001, respectively). Absolute and relative EZ reflectivity changes from postoperative month 1 to month 12 after macular hole surgery were significantly correlated with best corrected visual acuity improvement (p=0.012 and p=0.020, respectively). Conclusion: EZ reflectivity can be a predictor of functional and anatomical improvement after macular hole surgery.
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    Impact of Intravitreal Dexamethasone Implant on Vessel Diameters in Patients with Retinal Vein Occlusion
    (HINDAWI LTD, 2019-01-01) Tugan, Busra Yilmaz; Karabas, Levent; Ozkan, Berna
    Purpose. To investigate the vasomotor responses and diameter of retinal vessels in patients with macular edema secondary to retinal vein occlusion (RVO) who were treated with intravitreal dexamethasone implant. Methods. We enrolled 17 eyes of 17 patients with macular edema secondary to RVO. All patients were evaluated through optical coherence tomography and dynamic and static retinal vessel analysis, using the Dynamic Vessel Analyzer (Imedos, Jena, Germany) before administration (baseline) and 1week, 1month, and 2months after administration of intravitreal dexamethasone. Measurements of patients were compared to those of 17 eyes of age- and sex-matched control subjects. Results. In static analysis, arteriovenous ratio (AVR) in control subjects was 0.86 (0.80-0.88). In RVO patients, baseline AVR was 0.71 (0.54-0.84) and significantly lower than that in control subjects (p=0.016). Baseline AVR in the RVO group was significantly lower than AVR at month 1 and month 2 (p=0.001 and p<0.001, respectively). CRVE in healthy control subjects was 183.59 +/- 21.79 measurement units (MU) which was significantly different from CRVE of RVO eyes at baseline (207.00 +/- 26.35MU) (p=0.008). Static analysis showed a significant decrease of central retinal vein equivalent (CRVE) from baseline to 1week, 1month, and 2months (p<0.001, p<0.001, and p<0.001, respectively). CRAE in the control group was 176.24 +/- 22.45MU. CRAE in the RVO group was significantly lower at baseline, week 1, month 1, and month 2 compared to that in the control group (p=0.008, p=0.003, p=0.013, and p=0.011, respectively). Dynamic analysis showed that maximum venous and arterial dilations did not statistically differ from baseline to 1week, 1month, or 2months. Conclusion. Using the Dynamic Vessel Analyzer, we found that retinal veins in patients with RVO were significantly larger compared to those in the control group, and intravitreal dexamethasone treatment reduced the diameters of these veins.
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    Quantitative analysis of preclinical ocular microvascular changes in Multisystemic Inflammatory Syndrome in Children (MIS-C) detected by optical coherence tomography angiography
    (SPRINGERNATURE, 2021-01-01) Tugan, Busra Yilmaz; Sonmez, Hafize Emine; Atay, Kubra; Basar, Evic Zeynep; Ozkan, Berna; Karabas, Levent
    Objectives To evaluate the macular and optic nerve head (ONH) vascular density, foveal avascular zone area, and outer retina and choriocapillaris flow in Multisystemic Inflammatory Syndrome in Children (MIS-C) using optical coherence tomography angiography (OCTA). Methods Thirty-four eyes of 34 patients with MIS-C and 36 age and sex-matched healthy controls were investigated in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus (DCP), ONH, FAZ parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA. Results All VD parameters in SCP were significantly lower in MIS-C patients. There was no significant difference between the groups in VD parameters of both DCP and ONH, as well as FAZ area and FAZ perimeter. However, foveal density (FD-300) was significantly decreased in the MIS-C group. (p = 0.024). The outer retina flow area at 1 mm, 2 mm, and 3 mm radius and CC flow area at 1 mm and 2 mm radius were significantly lower in the MIS-C group than in the control group. Although CC flow area at 3 mm radius was decreased in the MIS-C group compared to healthy controls, the difference was not statistically significant. Conclusions We demonstrated a decreased vessel density in SCP, choriocapillaris flow area, and outer retinal flow area in MIS-C patients. Hence, we proposed that OCTA could reveal retinal and choroidal microvascular changes in MIS-C patients who were completely healthy before the diagnosis of MIS-C.