Retinal Microvascular Vessel Density Differences between Adult Athletes and Nonathletes.

SIGNIFICANCE: Regular physical activity may affect the neurovascular structures. Many studies have shown the positive effects of physical activity on ocular disorders such as glaucoma, retinopathy, and macular degeneration. Athletes were expected to have a better retinal vascular structure compared with the nonathletes. PURPOSE: This study aimed to evaluate the effects of regular physical activity on the retinal microvascular structure. METHODS: This observational and cross-sectional study was conducted between January and July 2020 with participants aged 20 to 35 years who had a visual acuity of ≥20/20, axial length of 22 to 24 mm, refractive defect spherical equivalent of ≤±1 D, and IOP of ≤21 mmHg. Updated AngioScan software (Navis version 1.8.0) of Nidek's RS-3000 Advance system was used to analyze the spectral-domain optical coherence tomography and optical coherence tomography angiography images. RESULTS: A total of 60 right eyes of 60 individuals were included in the study. Thirty subjects were in the athlete group, and 30 patients were in the nonathlete group. Sixteen of the individuals in the athlete group and 15 in the nonathlete group were women (P > .05). Retinal nerve fiber layer and ganglion cell complex thicknesses in all quadrants were thinner in nonathletes (P < .05). All of the Early Treatment Diabetic Retinopathy Study regions except central foveal subfield thickness were significantly higher in the athlete group (P < .05). In the nonathlete group, significantly reduced vessel densities of the superficial and deep capillary plexus and radial peripapillary capillary plexus, and the foveal avascular zone circularity index along with an increased foveal avascular zone perimeter and area were also detected (P < .05). CONCLUSIONS: Our study revealed that optical coherence tomography angiography measurements may be used in the determination of the effects of physical activity on retinal vascular structure changes.

Protection against experimental cisplatin-induced optic nerve toxicity using resveratrol: A rat model study.

AIM: To investigate the effects of resveratrol on oxidative stress and inflammation parameters and histological alterations in cisplatin-induced optic nerve damage in a mouse model. MATERIAL AND METHOD: Thirty-six albino Wistar male rats were divided into three groups as control, 5 mg/kg cisplatin-administered (Cis) and 5 mg/kg cisplatin + 25 mg/kg resveratrol-administered (Cis + Res) animals. At the end of the experimental period, the rats were sacrificed with high-dose (50 mg/kg) thiopental sodium, and their optic nerves were dissected. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS), total antioxidant status (TAS), tumour necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-KB) levels, and histopathological findings were assessed using the optic nerve tissues. RESULTS: In the Cis + Res group, the MDA, TOS, OSI, TNF-a and NFK-B levels were significantly lower and the tGSH and TAS levels were significantly higher compared with the Cis group (P = 0.001). In histological evaluations, there were dilated and congested blood vessels, destruction, oedema, degeneration, haemorrhage, and proliferating capillaries indicating the presence of inflammation and damage only in the Cis-administered group. However, in the Cis + Res group, the histological findings were very similar to the healthy controls. CONCLUSION: Resveratrol is a promising neuroprotective agent for cisplatin-induced optic nerve toxicity with its anti-oxidant and anti-inflammatory effects. Further investigations are needed to evaluate the possible therapeutic effects on other optic nerve toxicities.

The effects of vitamin B12 deficiency on retina and optic disk vascular density.

PURPOSE: In this study, we aimed to determine the alterations in the retina and peripapillary vascular density in patients with vitamin B12 deficiency. MATERIAL AND METHOD: The patients were divided into two groups regarding their vitamin B12 levels as the low vitamin B12 group (< 200 pg/ml) and the normal vitamin B12 group (≥ 200 pg/ml). The retinal nerve fiber layer thickness (RNFLT) and the central macular thickness (CMT) were measured through an SD-OCT analysis. The foveal avascular zone (FAZ), vessel density (VD) of the superficial capillary plexus (SCP), and deep capillary plexus (DCP) of the macula, and the VD of the radial peripapillary capillary plexus (RPCP) for the optic disk were determined by OCT-A. RESULTS: Thirty-three patients were in the low vitamin B12 group and 54 were in the normal group. The mean RNFLT measurements were significantly lower in the low vitamin B12 group (p = 0.001). The RPCP values in all quadrants were significantly lower in the patients with vitamin B12 deficiency (p = 0.001); moreover, there was a significant increase in the FAZ value with a decrease in both superficial (p = 0.001) and deep (p = 0.001) VDs. There was a significant positive correlation between the serum vitamin B12 levels and the RPCP values and superficial and deep VDs, while the FAZ value was negatively correlated with the vitamin B12 levels. CONCLUSION: Vitamin B12 deficiency has diverse effects on ocular structures and retinal vasculature. Decreased VDs and increased FAZ may be associated with severe ocular alterations in the long term, which should be further investigated.

The findings of corneal specular microscopy in patients with type-2 diabetes mellitus.

BACKGROUND: We aimed to compare the morphological characteristics of corneal endothelial cells in type 2 diabetic patients and age-matched healthy subjects by specular microscopy. We also aimed to determine the association of corneal morphological features with the general characteristics and laboratory data of diabetic patients, including disease duration, haemoglobin A1c (HbA1c) levels and urine albumin creatinine ratio. METHODS: A total of 195 diabetic patients and 100 healthy controls were enrolled in the study. All participants underwent a complete ophthalmological examination. Corneal endothelial measurements were performed using a noncontact specular microscopy. Laboratory data including serum fasting glucose, haemoglobin A1c levels, creatinine levels, and the urinary albumin-to-creatinine ratio were recorded. Diabetic patients were further subdivided into 3 groups according to the presence and stage of diabetic retinopathy. Specular microscopy findings and central corneal thickness of all patients were compared. RESULTS: The ECD and hexagonal cell ratio were significantly lower, while the average cell size, CV%, and central corneal thickness were determined to be significantly higher in diabetic patients than in healthy controls (p = 0.001). With the presence and advancement of diabetic retinopathy, the ECD and hexagonal cell ratio decreased, while the average cell size, CV%, and central corneal thickness increased. When correlation analysis was performed between corneal morphological features and laboratory data of diabetic patients, ECD showed a significant negative correlation with diabetes duration (p = 0.028). HbA1c levels, urinary albumin-creatinine ratio (p = 0.041), average cell size and CV showed a positive correlation with these parameters. CONCLUSION: In conclusion, keratopathy is an important complication of type 2 diabetes. With an increase in the stage of diabetic retinopathy, alterations in corneal findings also increased. In that respect, we can suggest that keratopathy should be evaluated more cautiously in diabetic patients.

Effects of adenosine triphosphate on methanol-induced experimental optic nerve damage in rats: biochemical and histopathological evaluation.

PURPOSE: Acute methanol exposure leads to systemic intoxication and toxic optic neuropathy. In this experimental study, we aimed to determine the protective effects of intravenous administration of ATP in methanol-induced optic neuropathy. MATERIALS AND METHODS: A total of 18 male albino Wistar rats weighing between 267 and 282 g were used for the experiment. The animals were divided into three groups as healthy control (HC), methanol (M), and methanol + ATP (M-ATP) groups. Distilled water was given to the healthy control group (n = 6) as the solvent, while 20% methanol was administered orally to the rats in M (n = 6) and M-ATP (n = 6) groups at a dose of 3 g/kg. Four hours after the administration of 20% methanol orally to the M-ATP group, ATP was injected intraperitoneally at a dose of 4 mg/kg. Eight hours after ATP injection, the animals were sacrificed by high-dose (50 mg/kg) thiopental anaesthesia and biochemical and histopathological examinations were performed on the removed optic nerve tissues. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS) and total anti-oxidant status (TAS) were analysed with biochemical tests. RESULTS: MDA, TOS and OSI were significantly higher and tGSH and TAS levels were significantly lower in methanol administered group compared with the healthy controls or M-ATP group (p: 0.001). There was not any significant difference between healthy controls and M-ATP group regarding the oxidative stress parameters. There was a significant destruction and increase in thickness and astrocyte numbers and edema-vacuolization in methanol administered group compared with the healthy controls or M-ATP group (p: 0.001). CONCLUSION: Intravenous ATP administration had a significant positive effect on the oxidative stress parameters and optic nerve structure in methanol-intoxicated rats. Antioxidant therapies should be considered in future studies as a possible therapy for methanol-induced toxic optic neuropathy.

Serum SCUBE-1 levels in patients with diabetic retinopathy.

PURPOSE: Signal peptide-CUB-Epidermal growth factor-like domain-containing protein 1 (SCUBE-1) is a protein expressed on the cell surface of endothelial cells and platelets. We aimed to determine the alterations in SCUBE-1 levels in patients at different stages of diabetic retinopathy (DR). MATERIALS AND METHODS: Participants were grouped into 4 regarding the presence and stage of diabetic retinopathy as follows: control group (n 32), patients without DR (n 39), patients with background DR (n 42) and patients with proliferative DR (n 55). Age, gender, duration of diabetes, fasting blood glucose levels, serum hemoglobin A1c (HbA1c), SCUBE-1 and malondialdehyde (MDA) levels of the patients were recorded. Central macular thickness and central macular volume were recorded and compared between groups. RESULTS: Totally 136 patients with diabetes mellitus and 32 control cases were included in the study. There is a significant increase in SCUBE-1 and MDA levels with an advance in DR. In correlation analysis, there was only a significant correlation present between serum SCUBE-1 and MDA levels (p 0.001) but not with other parameters. CONCLUSION: For the first time in literature, we determined a significant increase in SCUBE-1 levels in patients with DR. Moreover, with an advance in DR, SCUBE-1 levels were also increasing.

The effects of lutein on optic nerve injury induced by ethambutol and isoniazid: an experimental study.

AIM: Ethambutol and isoniazid are two major effective first line agents in tuberculosis treatment having some visual adverse effects. We aimed to determine the protective effects of lutein on oxidative optic neuropathy induced by ethambutol and isoniazid in an experimental model. MATERIAL AND METHOD: Totally 24 albino Wistar male rats were assigned into 4 groups, with 6 rats in each group as follows: healthy controls (HC group), 50 mg/kg ethambutol +50 mg/kg isoniazid administered group (EI), 0.5 mg/kg lutein +50 mg/kg ethambutol +50 mg/kg isoniazid administered group (LEI-05) and only Lutein (0.5 mg/kg) (LUT group) administered group. From the blood samples and tissues obtained from the rats, Malondialdehyde (MDA), total glutathione (GSH), interleukin 1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α) levels were studied. Histopathological evaluations were performed at the end of the study. RESULTS: Serum and tissue IL-1ß, TNF-α and MDA levels were the highest in EI group which were significantly lower in lutein administered group. On the other hand, serum and tissue total GSH levels were the lowest in EI group which were significantly higher in Lutein administered group. In histopathological evaluations, there were significant differences between EI group and all other three groups with edema and hemorrhage in connective tissue covering optic nerve, dilated and congested capillary, decrease in astrocytes and oligodendrocytes. CONCLUSION: Isoniazid and ethambutol induced toxic optic neuropathy although not common, may have some potential devastating effects on vision. Lutein is determined as an effective agent in prevention of isoniazid and ethambutol induced toxic optic neuropathy.

The effects of lycopene on alloxan induced diabetic optic neuropathy.

AIM: To determine the effects of lycopene treatment in prevention of diabetes associated inflammatory response and oxidative stress in an experimental model. With this aim we investigated the levels of oxidative stress markers including Malondialdehyde (MDA), and total oxidative status (TOS)together with inflammatory markers including nuclear factor- kappa B (NFKB) and tumor necrosis factor α (TNF-α) and antioxidants including total glutathione (TGSH), total oxidative status (TOS) and total anti-oxidative status (TAS) levels on eye tissue. MATERIAL AND METHODS: Totally 18 albino Wistar male rats (250-280 grams) assigned into three groups, with six rats in each group as follows: healthy group (HG), control group (CG), and lycopene group (LG). The diabetes was induced with alloxan administration in rats of CG and LG. Lycopene (4 mg/kg) was administered to the rats in LG once a day for 3 months. At the end of this period, the animals were sacrificed and their eyes were enucleated for histopathological evaluations. From the tissues, MDA, GSH, TOS, TAS, TNF-α and NF-κB levels were analyzed. RESULTS: MDA, TOS, OSI, NFKB and TNF-α levels were significantly higher, while TGSH and TAS levels were significantly lower in CG compared with HG (p < 0.001). On the other hand in LG; MDA, TOS, OSI, NFKB and TNF-α levels were significantly lower, while TGSH and TAS levels were significantly higher compared with CG (p < 0.001). Regarding histopathological findings, although there was severe damage on optic nerve of rats in CG; there was only a slight damage in lycopene administered group. CONCLUSION: For the first time in literature we determined that, lycopene was significantly effective in prevention of augmented inflammation and oxidative stress on eye tissue associated with diabetes, as well as the tissue damage on optic nerve. However, studies investigating the long-term clinical effects of lycopene on diabetic individuals are warranted.

The Effects of Intravitreal Ranibizumab, Aflibercept or Dexamethasone Implant Injections on Intraocular Pressure Changes.

BACKGROUND The aim of this study was to compare the alterations in intraocular pressure (IOP) values during the early postoperative period after intravitreal ranibizumab, aflibercept, or dexamethasone implant injections. MATERIAL AND METHODS In this retrospective study, a total of 188 patients were grouped into 3 groups: the ranibizumab group, the aflibercept group, and the dexamethasone group. Ocular axial length (AXL) and anterior chamber depth (ACD) were measured in the pre-injection period. IOP was measured just before the injection at 1 minute,10 minutes, 1 hour, 1 day, and 1 month after injection. RESULTS There was a transient peak in the ranibizumab group and the aflibercept group at 1 minute that started to decrease at 10 minutes and IOP values returned to preoperative values at approximately 1 hour. Similar alterations were also determined for the dexamethasone group with a lesser increase noted. In the correlation analysis, only alterations in IOP levels at 1 minute were negatively correlated with preoperative AXL values. There was not any correlation between preoperative AXL or ACD values and IOP alterations at any other time points. CONCLUSIONS There was a sudden, transient increase in IOP values after intravitreal ranibizumab or aflibercept injections; which return to normal values in a short time without requirement of any medical treatments. This transient peak was determined to be negatively correlated with the preoperative AXL.

Effects of Pycnogenol on cisplatin-induced optic nerve injury: an experimental study.

AIM: To determine the effects of Pycnogenol on cisplatin-induced optic nerve damage. MATERIAL AND METHOD: Totally 18 albino Wistar male rats were assigned into three groups, with six rats in each group as follows: healthy controls (HC group), only cisplatin (2.5 mg/kg) administered group (CIS group) and Pycnogenol (40 mg/kg) + cisplatin (2.5 mg/kg) administered group (PYC group). We analyzed the levels of malondialdehyde (MDA) as a marker of lipid peroxidation and oxidative stress, total glutathione (tGSH) as a marker of antioxidant status, nuclear factor-kappa B (NF-κB) and tumor necrosis factor alpha (TNF-α) as inflammatory markers, total oxidative status (TOS) and total antioxidant status (TAS) on eye tissue together with histopathological evaluation of optic nerve in an experimental model. RESULTS: In CIS group MDA, TOS, TNF-α and NF-κB levels were statistically significantly higher (p < 0.001) than HC group while tGSH and TAS levels were significantly lower (p < 0.001). On the other hand, in PYC group MDA, TOS, TNF-α and NF-κB levels were statistically significantly lower (p < 0.001) than CIS group while tGSH and TAS levels were significantly higher (p < 0.001). CONCLUSION: Pycnogenol pretreatment was highly effective in preventing augmentation of cisplatin-induced oxidative stress and inflammation in eye tissue.

A comparison of the effects of perindopril arginine and amlodipine on choroidal thickness in patients with primary hypertension

Background/aim: This study aimed to investigate the effects of two different medical treatment options on choroidal thickness (CT) in patients with primary hypertension. Materials and methods: Forty newly diagnosed primary hypertension patients and 21 healthy volunteers were included. The patients were randomly divided into two subgroups. Group I started on perindopril arginine and Group II started on amlodipine. Submacular CT using optical coherence tomography (OCT) was measured before treatment and at the third and sixth months after treatment. Results: Initial mean arterial pressure (MAP) values in Groups I and II and the control group were 113.4, 109.8, and 89.4 mmHg, respectively, and mean CT values were 257.9, 286.5, and 300.9 µm. Mean MAP values in Groups I and II and the control group at the sixth month after treatment were 99.7, 99.6, and 90.2 mmHg, respectively, and mean CT values were 293.1, 286, and 297.4 µm. Analysis of the changes occurring during the study revealed significant variation in MAP in Groups I and II, and in CT in Group I only. Conclusion: A gradual increase in CT developed with perindopril arginine therapy in patients with primary hypertension, while no significant change occurred in CT in the amlodipine group.

Assessment of the optic nerve, macular, and retinal vascular effects of COVID-19.

OBJECTIVE: To evaluate the effects of SARS-CoV-2 infection on the optic nerve, macula, and retinal vascular structures. METHODS: This study included 129 participants recovering from COVID-19 and 130 healthy control subjects aged 18 to 55 years. The study was designed as observational and cross-sectional and was conducted between June 2020 and February 2021. The average thicknesses of the retinal nerve fibre layer (RNFL), ganglion cell complex (GCC), and macula also were measured using a spectral domain optical coherence tomography analysis. The vessel densities of the superficial and deep capillary plexuses of the macula, foveal avascular zone, and radial peripapillary capillary plexus of the optic disc were quantified by optical coherence tomography angiography. RESULTS: In all quadrants, the RNFL and GCC were thinner in patients with neurologic symptoms of COVID-19 (p < 0.05). None of the measurements of the Early Treatment Diabetic Retinopathy Study regions significantly differed between patients with and without COVID-19 symptoms (p > 0.05). The foveal avascular zone area, perimeter, circularity index, and vessel densities (%) of the global and inner and outer circles of superficial capillary plexuses and deep capillary plexus and global and superior and inferior halves of the radial peripapillary capillary plexus measurements were found to significantly differ between the symptomatic COVID-19 group and the asymptomatic COVID-19 and control groups (p < 0.05). CONCLUSION: RNFL and GCC thickness evaluation with optical coherence tomography and vessel density evaluation with optical coherence tomography angiography can be considered remarkable diagnostic methods for retinal neurovascular abnormalities and a biomarker for microvascular abnormalities after infection with SARS-CoV-2.

Changes in optical coherence tomography angiography in patients with vitamin D deficiency.

PURPOSE: 25-hydroxyvitamin D [25(OH)D] sufficiency has critical biological importance for the human body. Although there are several studies on the association between serum 25(OH)D levels and macular structure, the data in this regard are limited. This study mainly aimed to investigate macular microvascular structure using optical coherence tomography angiography (OCTA) in 25(OH)D deficiency. STUDY DESIGN: Prospective, single-center, clinical study. METHODS: The study included 82 eyes of 82 patients with 25(OH)D deficiency (Group I) and 50 eyes of 50 healthy subjects (Group II). All participants underwent OCTA examinations. The foveal avascular zone (FAZ) and superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) measurements of the participants were statistically compared between the patients and healthy subjects. RESULTS: The mean 25(OH)D levels measured from the venous blood samples of the participants were 7.61 ± 3.27 ng/mL in Group I and 25.39 ± 4.16 ng/mL in Group II, and the difference between these values was statistically significant (p < 0.0001). The FAZ measurement was significantly higher in Group I. The VDs of the SCP and DCP measurements were significantly higher in Group II. When the central macular thickness values of the participants were compared, Group II had a significantly higher value, but there was no significant difference in the central macular volume and retinal nerve fiber layer thickness analyses. CONCLUSION: The results showed that the FAZ area was significantly higher and the VDs of SCP and DCP were significantly lower in the patients with 25(OH)D deficiency. We found that 25(OH)D deficiency affected macular microvascular architecture.

Comparison of Six Methods of Central Corneal Thickness Measurement in Healthy Eyes.

OBJECTIVES: Several methods of measuring central corneal thickness (CCT) have been compared, however, the data are still limited and conflicting. The aim of this study was to determine the agreement of CCT measurements performed in healthy eyes using ultrasound pachymetry (USP), non-contact tono/pachymetry, specular microscopy, biometry, Scheimpflug-based corneal topography, and optical coherence tomography (OCT). METHODS: All of the participants underwent a complete ophthalmological examination. The CCT of all of the eyes included was measured using 6 different methods. The agreement between the methods was analyzed using the mean difference and Bland-Altman analysis based on a 95% limits of agreement. RESULTS: A total of 64 patients with a mean age of 40.96±14.52 years (range: 20-78 years) were included in the study. The mean CCT value was 552.10±35.65 µm, 550.40±35.55 µm, 554.67±35.49 µm, 545.39±34.21 µm, 546.25±35.49 µm, and 552.64±33.59 µm using USP, non-contact tono/pachymetry, non-contact specular microscopy, biometry, Scheimpflug-based corneal topography, and OCT, respectively. The bias values determined by Bland-Altman plots were -1.70, -2.56, 6.71, 5.85, and -0.53 for tono/pachymetry, specular microscopy, biometry, topography, and OCT, respectively. OCT demonstrated the lowest bias compared to USP. The overall intraclass correlation coefficient was 0.961 (range: 0.945-0.974) with a 95% confidence interval. CONCLUSION: All of the CCT measurements obtained using non-contact tono/pachymetry, non-contact specular microscopy, biometry, Scheimpflug-based corneal topography, and OCT were consistent with the USP measurements of healthy controls. Larger prospective studies to determine the interchangeability of different methods for CCT measurements in pathological conditions are warranted.

Assessments of vessel density and foveal avascular zone metrics in multiple sclerosis: an optical coherence tomography angiography study.

BACKGROUND/OBJECTIVES: To investigate optical coherence tomography angiography (OCT-A) findings of foveal avascular zone (FAZ) metrics and macular & peripapillary vessel densities (VD) in subjects with multiple sclerosis (MS). METHODS: The study design was prospective and cross-sectional. FAZ metrics and VDs of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) along with the structural OCT measurements were scanned by using the Nidek's RS-3000 Advance in MS patients and healthy controls. All subject also underwent an assessment of visual evoked potentials (VEPs). The relationships between the OCT-A parameters with other clinical findings were analysed. RESULTS: Forty-seven MS patients (94 eyes) and 61 healthy volunteers (122 eyes) were included in this study. Thirty-five eyes of the MS patients had an ON history. The structural OCT measurements were significantly differed between the groups (P < 0.001). All FAZ metrics were inversely correlated with central foveal thickness (CFT) (P < 0.001). The FAZ area and perimeter were inversely correlated with the VD of both SCP and DCP (P < 0.05). The VDs of SCP and DCP were significantly differed between the study groups (P < 0.001). The VEP latency was inversely correlated with the retinal nerve fibre layer, macular and ganglion cell layer thicknesses, the VD of SCP, and the VD of the DCP (P < 0.001). CONCLUSIONS: Based on OCT angiography, VDs of macular and peripapillary area may be useful in detecting damage from ON in patients with MS.

The Relation of Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio with High Axial Myopia.

Purpose: To investigate the relation between high axial myopia and neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) values.Methods: Seventy-nine cases were enrolled, 50 myopic and 29 emmetropic. All participants were assigned into three groups: Group I (high myopia with no retinal involvement), Group II (high myopia with retinal involvement) and Group III (control). NLR and PLR values calculated from blood tests were compared among the groups.Results: Mean NLR levels were 2.23 ± 0.78 in Group I, 2.36 ± 1.06 in Group II, and 1.57 ± 0.33 in Group III. Mean PLR levels were 114.62 ± 23.21 in Group I, 145.16 ± 52.36 in Group II, and 91.42 ± 18.73 in Group III. NLR and PLR values in the high myopia groups were significantly higher than in the control group.Conclusion: NLR and PLR values in cases with high axial myopia were higher than in the emmetropic group. Higher inflammation in the degenerative myopic group in particular may be related to pathological chorioretinal changes.

Evaluation of the Optic Disc and Macula in Healthy Children Using Optical Coherence Tomography Angiography

Objectives: To perform the measurements of the optic disc and macula in healthy children using optical coherence tomography angiography (OCTA) in order to determine the normative data values and compare these by age, gender, spherical equivalent (SE), and axial length (AL). Materials and Methods: A total of 146 eyes belonging to 146 healthy children (74 girls, 72 boys) aged 6 to 16 years were included in this prospective study. Refraction and biometry measurements were performed. Retinal nerve fiber layer thickness (RNFLT), central macular volume, and central macular thickness (CMT) were measured by optical coherence tomography (OCT) after dilatation. Using the OCTA device, foveal avascular zone (FAZ) area, vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the macula, and the VD of the radial peripapillary capillary plexus (RPCP) of the optic disc were recorded. Results: The mean age of the study group was 11.27±3 years, the mean AL was 23.39±1.18 mm and the mean SE was -1.31±1.61 diopters. The mean FAZ area was 0.3±0.09 mm2, the mean SCP-VD was 43.88±3.4%, the mean DCP-VD was 39.6±3.55%, and the mean RPCP-VD was 52.47±3.42%. When the relationship between the OCTA measurements and the SE and AL values were analyzed, there was no statistical significance (p>0.05). When age and OCTA measurements were compared, only DCP-VD values were found to significantly decrease with increasing age (p=0.015). There was no significant difference in OCTA measurements based on gender (p>0.05). Similarly, no statistical age-based differences were observed in RNFLT, CMV and CMT values (p>0.05). Conclusion: With its short procedure time and no dye requirement, OCTA can be safely used in the evaluation of the optic disc and macular perfusion in children. Determination of normative values in children will be useful in detecting pathologic changes in tissue in patients with retinal diseases.

Alterations in optical coherence tomography angiography findings in patients with high myopia.

PURPOSE: The aim of this study was to determine the macular changes using optical coherence tomography (OCT) and OCT-angiography (OCT-A) in eyes with high myopia. Determining the alterations in vascular structures can provide a clearer understanding of the pathophysiological mechanisms of this disease and help define new treatment options and preventive measures. MATERIALS AND METHODS: Ninety-two patients with high myopia (axial length ≥ 26 mm) and 70 control cases without any known systemic or ocular diseases were enrolled in this prospective study. One eye of each patient was included in the statistical analyses. RESULTS: Retinal nerve fiber layer (RNFL) thickness and Early Treatment Diabetic Retinopathy Study (ETDRS) macula map values were lower in myopia compared with the controls. Both superior and inferior ganglion cell complex (GCC) thicknesses were significantly thinner in the high myopia compared with the controls (p < 0.001). Regarding the OCT-A findings, although superficial or deep foveal avascular zones (FAZ) did not significantly differ between the two groups, the density values of superficial and deep microvessels were significantly lower in the high myopia group compared with the control cases. CONCLUSIONS: In patients with high myopia, with an increase in the axial length and a decrease in RNFL and GCC thicknesses, the vascular densities of the superficial and deep retina were reduced in the macular region.

Thiol-Disulfide Homeostasis and Serum Ischemia Modified Albumin Levels in Patients with Primary Open-Angle Glaucoma.

Aim: Glaucoma is an optic neuropathy causing progressive impairment of visual functions. We aimed to assess the alterations in thiol-disulfide homeostasis and serum ischemia modified albumin (IMA) levels, which are the determinants of antioxidant status, in patients with primary open-angle glaucoma (POAG). Material and Method: A total of 140 eyes from 70 patients with POAG and 174 eyes of 87 healthy, control cases were included in the study. All study participants underwent a complete ophthalmic evaluation. Alterations in serum thiol-disulfide homeostasis and IMA levels were measured in all participants. Results: IMA levels were significantly higher in glaucoma group (p:0.001). Native thiol, Total thiol and Native/Total thiol ratio were significantly decreased while Disulfide, Disulfide/Native thiol, and Disulfide/Total thiol ratios were significantly higher in glaucoma group (p:0.001). There was no significant difference regarding central corneal thickness (CCT), iridocorneal angle, albumin, IMA and adjusted IMA levels in patients with different stages of glaucoma. In correlation analysis, there was a negative correlation between Native thiol, Total thiol and Native/Total thiol ratio and disease period, number of daily drops required and stage of the disease in glaucoma patients. There was also a positive correlation between Disulfide, Disulfide/Native thiol and Disulfide/Total thiol levels and the disease activity. Conclusion: In patients with POAG, thiol-disulfide homeostasis is disturbed in the favor of pro-oxidant molecules and IMA levels are increased, indicating the presence of augmented oxidative stress. In that aspect, systemic and local anti-oxidant treatments may be new targets in glaucoma treatment. Larger, prospective studies about the role of anti-oxidants in prevention and treatment of POAG are warranted.

The effects of thiamine pyrophosphate on ethanol induced optic nerve damage.

BACKGROUND: We aimed to determine the protective effects of thiamine pyrophosphate on ethanol induced optic neuropathy in an experimental model. METHODS: The rats were assigned into 4 groups, with 6 rats in each group as follows: healthy controls (HC group), only ethanol administered group (EtOH group), ethanol + thiamine pyrophosphate (20 mg/kg) administered group (TEt-20 group), and only thiamine pyrophosphate (20 mg/kg) (TPG group) administered group. To the rats in TEt-20 and TPG groups, 20 mg/kg thiamine pyrophosphate was administered via intraperitoneal route. To the rats in HC and EtOH groups, the same volume (0.5 ml) of distilled water as solvent was applied in the same manner. To the rats in TEt-20 and EtOH groups, one hour after application of thiamine pyrophosphate or distilled water, 32% ethanol with a dose of 5 g/kg was administered via oral gavage. This procedure was repeated once a day for 6 weeks. From the blood samples and tissues obtained from the rats, Malondialdehyde (MDA), reduced glutathione (GSH), interleukin 1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α) levels were studied. Histopathological evaluations were performed to the optic nerve tissue. RESULTS: Serum and tissue IL-1ß, TNF-α and MDA levels were the highest in EtOH group which were significantly lower in thiamine pyrophosphate administered group (TEt-20 group) (p: 0.001). Serum and tissue reduced GSH levels were the lowest in EtOH group which were also significantly higher in TEt-20 group (p:0.001). In histopathological evaluations, in EtOH group there was obvious destruction and edema with hemorrhage and dilated blood vessels which were not present in any other groups. CONCLUSIONS: There was an apparent destruction in ethanol administered group in histopathological analyses with an augmented level of oxidative stress markers and all those alterations were prevented with concomitant thiamine pyrophosphate administration. These protective effects of thiamine pyrophosphate are extremely important in chronic ethanol consumption. Clinical studies are warranted to define the exact role of thiamine pyrophosphate in prevention of ethanol induced optic neuropathy.