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  • Küçük Resim
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    Disc–fovea distance and choroidal thickness: is there a relationship?
    (SAGE PUBLICATIONS LTD, 2022) Cevher, Selim; Üçer, Mehmet Barış; Şahin, Tayfun
    Background: The distance between the optic disc center and the fovea is a biometric parameter; however, it is unclear whether DFD (disc–fovea distance) affects the choroidal thickness. Objective: The aim of this study is to investigate the association between DFD and choroidal thickness. Design: This is a prospective, and cross-sectional study. Methods: Two hundred fifty eyes of 250 healthy participants were examined in terms of DFD, age, axial length, spherical equivalent, and choroidal thickness. Inclusion criteria included aged between 20–40 years, no posterior segment disorders, and participants with best-corrected visual acuity (10/10 according to Snellen’s chart). Participants with high hypermetropia (>4 diopter) or myopia (>6 diopter) or any systemic disease likely to affect choroidal thickness were excluded. Choroidal thickness measurements were performed at subfoveal, 1.0 mm temporal, and 1.0 mm nasal using the enhanced-depth imaging optical coherence tomography. Results: The mean age of all the participants was 26.21?±?5.73 years, mean DFD was 4634.29?±?274.70 µm, mean axial length was 23.62?±?0.83 mm, and mean spherical equivalent was ?0.61?±?1.06 diopter. The mean subfoveal, nasal, and temporal choroidal thicknesses were 388.73?±?90.15 µm, 351.26?±?88.09 µm, and 366.50?±?79.56 µm, respectively. A negative correlation was found between subfoveal, nasal, and temporal choroidal thicknesses and axial length (r?=??0.157, p?=?0.013; r?=??0.168, p?=?0.008; r?=??0.174, p?=?0.006, respectively). Insignificant correlation was found between choroidal thicknesses and spherical equivalent (p?>?0.05). There was not a statistically significant correlation between DFD and subfoveal, nasal, and temporal choroidal thicknesses (r?=??0.028, p?=?0.655; r?=?0.030, p?=?0.641; r?=??0.025, p?=?0.699, respectively). In addition, there was not a statistically significant correlation between age and choroidal thickness. Conclusion: This study shows that DFD and spherical equivalent do not affect choroidal thickness; axial length negatively affects choroidal thickness. In addition, age does not affect choroidal thickness between 20 and 40 years.
  • Küçük Resim
    Öğe
    How does anisometropia affect the choroidal vascularity index?
    (WOLTERS KLUWER MEDKNOW PUBLICATIONS, 2022) Cevher, Selim; Şahin, Tayfun
    Purpose: To investigate the choroidal vascularity index (CVI) and morphological features of the choroid in anisometropic amblyopia. Methods: In this prospective cross sectional study, 39 patients with unilateral anisometropic amblyopic patients and 33 eyes of 33 healthy control participants were involved. These participants were examined in terms of axial length (AL), spherical equivalent (SE), central macular thickness (CMT), choroidal thickness (CT), total choroidal area (TCA), luminal area (LA), stromal area (SA), LA/SA ratio, and CVI. All parameters were compared between amblyopic eyes, healthy fellow eyes, and healthy control eyes. The Shapiro–Wilk tests, Chi square test, the paired t test, Wilcoxon signed rank test, Mann–Whitney U test, Kruskal–Wallis test, and Pearson/Spearman correlation tests were used. Results: In the hyperopic patients; SE, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA, and CMT were greater in amblyopic eyes than in healthy fellow eyes and control eyes (P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively), and CVI, LA/SA ratio, and AL were smaller in amblyopic eyes than in healthy fellow eyes and control eyes ([P < 0.001, P = 0.006], P < 0.001, and P < 0.001, respectively). In the myopic patients, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA values were statistically smaller in amblyopic eyes than in healthy eyes and control eyes ([P < 0.001, P = 0.002), [P = 0.004, P = 0.012], [P = 0.012, P = 0.032], [P < 0.001, P = 0.013], [P < 0.001, P = 0.024], and [P < 0.001, P = 0.047], respectively). The differences in the AL and choroidal parameters were due to myopia and hyperopia. Conclusion: The choroidal structural parameters of the amblyopic eyes were different from that of the healthy eyes.
  • [ X ]
    Öğe
    The association between plasma concentration of pigment epithelium-derived factor and diabetic retinopathy
    (WALTER DE GRUYTER GMBH, 2023) Şahin, Tayfun; Karabulut, Alpaslan
    Objectives Diabetic retinopathy (DRP) is one of the most common microvascular complications of diabetes. The pigment epithelium-derived factor (PEDF) is a protein that is one of the most potent angiogenesis inhibitors. The effect of blood PEDF concentration on DRP formation remains unclear. The present study aimed to determine whether the plasma concentration of PEDF is effective on the appearance of DRP. Methods The present study consisted of 62 patients with diabetes mellitus and 20 healthy participants. The patient group included 28 patients with non-proliferative DRP, 13 with proliferative DRP, and 21 diabetic patients without DRP. The PEDF levels in patient serum samples were detected through the ELISA method. The body mass index of the participants was calculated. Results Serum PEDF levels of diabetic patients (1.533 ± 0.233??g/mL) were found to be lower (2.163 ± 0.343??g/mL) than healthy participants (p=0.002). The PEDF levels were similar in the DRP and non-DRP groups (p=0.337). The plasma PEDF level decreased along with the progression of DRP (p=0.001). Conclusions The PEDF concentration in the blood decreases along with the increase of DRP grade. Decreased blood concentration of PEDF may be important to predict microvascular complications. Agents containing PEDF may be used intraocularly/systemically for therapeutic purposes to prevent vascular complications of diabetes in the near future.