Ayse Oner

Ocular blood flow in patients with obstructive sleep apnea syndrome (OSAS).

BackgroundSleep-related disorders are among the important risk factors for neurovascular diseases. Obstructive sleep apnea syndrome (OSAS) is characterized by snoring, excessive daytime sleepiness, and insomnia. Our aim was to investigate the presence of glaucoma in patients with OSAS and to reveal vascular pathology related to the pathogenesis of glaucoma in those patients.Patients and methodsThe study included 31 patients with OSAS and 25 control subjects. Orbital Doppler ultrasonography was used to determine the resistivity index (RI) in the ophthalmic artery and central retinal artery. All patients and controls underwent perimetric examination.ResultsThe prevalence of glaucoma in the group of patients with OSAS was 12.9% (4/31); all of these 4 patients with glaucoma were in the “severe” OSAS group. No statistically significant difference was found between ophthalmic artery resistivity index (OARI), central retinal artery resistivity index (CRARI), and intraocular pressure (IOP) between patients and controls (p > 0.05). There was a positive correlation between OARI and mean defect (MD), CRARI and MD, and CRARI and loss variance (LV) values (p < 0.05). There was also a positive correlation between IOP and the apnea-hypopnea index (AHI) (p = 0.001).ConclusionsIn patients with OSAS, a high prevalence was found and it is interesting to note that all of the four glaucoma patients were in the severe OSAS group. The positive correlation observed between IOP and AHI suggests that increased IOP values may reflect the severity of OSAS. The positive correlation between OARI and MD and also between CRARI and MD as well as LV suggests that visual field defects may be due to optic nerve perfusion defects and these field defects also increase as the RI increases.

Serum Paraoxonase 1 Activity and Lipid Peroxidation Levels in Patients with Age-Related Macular Degeneration

Our objective was to investigate antioxidant paraoxonase 1 (PON1) activity together with malondialdehyde (MDA) levels to evaluate oxidative stress in patients with age-related macular degeneration (AMD), an important cause of blindness in the elderly population. Serum PON1 activity and MDA levels were analyzed in 37 patients with AMD and compared with 29 healthy controls using a spectrophotometric method. Serum MDA levels were significantly higher in the patient group (2.76 ± 1.28 nmol/ml) than controls (1.00 ± 0.36 nmol/ml; p < 0.001), whereas PON1 activity was lower in the patient group (132.27 ± 63.39 U/l) than controls (312.13 ± 136.23 U/l; p < 0.001). There was a negative correlation between MDA and PON1 levels (r = –0.470, p < 0.001). We conclude that the observed increase in MDA levels may be related to decreased PON1 activity; the present data also demonstrated that an obvious negative correlation between PON1 activity and MDA levels exists in patients with AMD. PON1 is also an antioxidant agent, therefore effective antioxidant therapy to inhibit lipid peroxidation is necessary and agents to increase PON1 activity may be a therapeutic option in AMD.

Serum paraoxonase activity is decreased in the active stage of Behçet’s disease

Aims: To evaluate paraoxonase1 (PON1) activities and malondialdehyde (MDA) levels, one of the end products of lipid peroxidation induced by reactive oxygen species in patients with Behçet’s disease (BD) in the active stage. Methods: Serum MDA levels and PON1 levels were measured spectrophotometrically in 16 patients with BD in the active stage of the disease and in 15 healthy subjects who constituted the control group. Results: In the BD group, median (range) serum PON1 and MDA levels were 149.64 U/l (88.02–281.68) and 1.21 nmol/ml (0.90–3.42), respectively. In the control group, median (range) serum PON1 and MDA levels were 206.86 U/l (114.43–422.52) and 0.72 nmol/ml (0.50–1.12), respectively. There was a statistically significant decrease in serum PON1 levels (p = 0.02) and an increase in serum MDA levels (p<0.001) in patients with BD in the active stage when compared to controls. Conclusion: Endothelial damage and increased polymorph nuclear leucocyte activity in the active stage of BD could result in a pro-oxidation environment which, in turn, results in decreased antioxidant PON activity and increased lipid peroxidation as evidenced by increased MDA levels.

Obstructive sleep apnoea prevalence in non-arteritic anterior ischaemic optic neuropathy

Aims The aim of this study was to show the prevalence of obstructive sleep apnoea (OSA) in non-arteritic anterior ischaemic optic neuropathy (NAION). Methods 20 patients diagnosed with NAION were included in the study. 20 age and sex matched subjects with similar risk factors for NAION, such as diabetes mellitus (DM) and hypertension (HT), constituted the control group. All cases underwent polysomnography for investigation of the presence of OSA. Cases with an Apnoea–Hypopnoea Index >5 were accepted as having OSA. Results Mean ages of the patients and controls were 60.90±8.14 and 61.15±7.23 years, respectively. There were no significant differences between the patient and control groups in terms of age, gender, body mass index, smoking/alcohol consumption or systemic diseases. In the patient group, 85% were diagnosed with OSA compared with 65% in the control group (p>0.05). Conclusions We found a high prevalence of OSA in patients with NAION but it was also high in the control group (p>0.05). This may be due to the fact that the two groups were matched for the same risk factors for NAION. The study indicates that OSA is not a risk factor for NAION in itself but is the contributing factor as it has effects on the vascular endothelium in DM, HT and atherosclerosis.

The role of advanced oxidation protein products and total thiols in diabetic retinopathy.

Purpose This study aimed to investigate the role of protein peroxidation by detecting the serum levels of advanced oxidation protein products (AOPP), a novel marker for the degree of oxidative damage to proteins, and total thiol as a marker of antioxidant status in diabetic patients with or without diabetic retinopathy (DR) and to compare the results with those of control subjects. Methods The study groups consisted of two separate subgroups: 1) 37 patients (14 male, 23 female) with noninsulin-dependent diabetes mellitus (NIDDM) showing diabetic retinopathy (DR) and 2) 20 patients with NIDDM and without any signs of DR (9 male, 11 female); 26 healthy non-diabetic control subjects (15 male, 11 female) were selected from the patients attending our department for refractive disorders. Venous blood samples of all participants were collected in the morning after an overnight fast, and serum samples stored at −70°C until assay for AOPP, and total thiol. Results AOPP levels were significantly higher in diabetic patients with (210.9±73.0 μmol/L) or without DR (222.7±94.4 μmol/L) when compared to those of controls (152.4±72.04 μmol/L) (p=0.004). Even though the difference was not statistically significant (p=0.095), total thiol levels in cases with DR (278.7±139.1 μmol/L) were lower than those without DR (334.0±129.4 μmol/L) and controls (353.2±145.6 μmol/L). Correlation tests did not reveal any association between these parameters and age, sex, or duration of DM. Conclusions The present study suggests that increased protein oxidation may contribute to the pathogenesis of DR.

Ocular trauma in Turkey: a 2-year prospective study

This 2-year prospective study was conducted to identify those at risk for ophthalmologic emergencies, to define the risk factors and reasons for eye injuries, to analyze treatment options, and to compare findings with those of previous studies. A total of 203 patients (74% male, mean age 27.3±13.9 y, 51% right eye injuries, 44% left eye injuries, 5% bilateral injuries) with injury to 208 eyes who presented to the emergency department for treatment were included in this study. All patients were evaluated by an ophthalmologist, who completed a formal questionnaire. Information recorded included demographic data, details of the eye injury, whether eye protection was used, and the type, location, and mechanism of injury to the eye. Mechanism of injury was categorized as blunt, sharp, or a combination. The ophthalmologist reported the time that had passed between occurrence of injury and presentation for treatment. Each patient was examined by the ophthalmologist, and findings, diagnosis, and treatment were documented. Of treated patients, 93% were hospitalized, most of whom required surgical treatment. One hundred (48%) injuries were related to blunt trauma and 86 (41%) to sharp device trauma. Only 10 (4%) patients were wearing protective eyewear when injured. Ruptured globe was the most common diagnosis of hospitalized patients and the most frequent cause of this was corneal lesions; subconjunctival hemorrhage was the most common diagnosis among nonhospitalized patients. In this study, the leading cause of eye injury was workplace accidents, probably attributable to growing industrialization in the region. Ocular trauma continues to be an important health problem in Turkey. Investigators believe that with education about and use of proper eye protection, 90% of eye injuries could be prevented.

Overexpression of vascular endothelial growth factor receptor 2 in pterygia may have a predictive value for a higher postoperative recurrence rate

Background To investigate the expression levels of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 1 (VEGFR-1) and VEGFR-2 in pterygium and to clarify the prognostic significance of these expressions in pterygia. Methods A total of 40 surgically excised pterygia and 9 normal conjunctivae were immunohistochemically studied applying the streptavidin–biotin method in paraffin-embedded tissue sections. Monoclonal antibodies were targeted against VEGF, VEGFR-1 and VEGFR-2 proteins. At the sixth postoperative month, the recurrence rate was graded on a scale of 1–4. Results The mean percentage of VEGF-positive epithelial cells was comparable in pterygium and normal conjunctivae. However, the pterygium group presented higher expression levels of VEGF in pterygia endothelial cells (p=0.05). In terms of VEGFR-1 expression in epithelial cells, no statistically significant difference was found between two groups (p=0.658). However, normal conjunctivae exhibited higher expression levels of VEGFR-1 in endothelial cells (p=0.002). Epithelial cells in pterygium presented higher combined scores of VEGFR-2 (87.5% and 22.2%, respectively) (p=0.013). While higher expression levels of VEGFR-2 were documented in pterygia endothelial cells, no VEGFR-2 immunoreactivity was observed in the endothelial cells of normal conjunctivae (p<0.001). Expression levels of VEGFR-2 in epithelial cells and endothelial cells were positively correlated with the postoperative recurrence grading system (p<0.001 and τ=0.627, p=0.001 and τ=0.508, respectively). Conclusions The results suggest that VEGF may play a key role through VEGFR-2 in the pathogenesis of pterygium. Moreover, overexpression of VEGFR-2 in pterygia may have a predictive value for a higher postoperative recurrence rate.

Evaluation of ocular surface damage and dry eye status in chronic hepatitis C at different stages of hepatic fibrosis.

Purpose: The purpose of this study was to explore changes in ocular surface and tear function parameters in chronic hepatitis C at different stages of hepatic fibrosis. Methods: Fifty-four patients with biopsy-proven chronic hepatitis C and 54 age- and sex-matched healthy control subjects without systemic hepatitis C infection were examined with the Ocular Surface Disease Index questionnaire, Schirmer with and without anesthesia, tear film breakup time, and scoring of ocular surface Lissamine green staining using modified Oxford and van Bijsterveld scoring systems and corneal fluorescein staining. Results: Patients with chronic hepatitis C scored significantly worse than the control subjects on all parameters: modified Oxford scores of Lissamine green staining (5.5/3.0; P <0.001), Oxford and van Bijsterveld scores (4.0/2.0; P <0.001), and corneal fluorescein staining (1.5/0.0; P = 0.001). The chronic hepatitis C group also had higher Ocular Surface Disease Index scores than the control subjects (22.3/13.7; P = 0.001). Schirmer with and without anesthesia and tear film breakup time scores were found to be lower in patients with chronic hepatitis C (P <0.001). Moreover, patients with advanced stages of hepatic fibrosis (stages 4-6) had significantly lower values of tear film breakup time and worse Ocular Surface Disease Index scores and ocular surface vital dye staining than those with initial stages of hepatic fibrosis (stages 0-3). Conclusion: Patients with chronic hepatitis C, especially those with advanced stages of hepatic fibrosis, were more likely to exhibit severe ocular surface damage and signs of dry eye.

Pattern VEP is a useful technique in monitoring the effectiveness of occlusion therapy in amblyopic eyes under occlusion therapy

PurposeTo evaluate the effectiveness and clinical significance of pattern visual evoked potential (P-VEP) parameters on visual acuity in amblyopic patients under occlusion therapy.MethodsA total of 34 consecutive children with anisometropic amblyopia were included in this study. All patients underwent a full initial ophthalmologic and orthoptic evaluation. P-VEP test was performed in all cases and binocular vision was tested and recorded with Worth’s four-dot test and Bagolini striated glasses at each visit. Part-time occlusion therapy was performed by using adhesive patches.ResultsThe mean (±SEM) cycloplegic refractive error was +5.6 ± 0.6 diopters (D) in the amblyopic eyes and +1.8 ± 0.2 D in the normal eye. The mean levels of best-corrected visual acuity were statistically differed between each measurement for occlusion therapy (for each, p < 0.05). The ratio of the patients with binocular vision increased after 6 months occlusion therapy and the difference was statistically significant (p<0.05). In addition, P100 amplitude improved at each visit and the difference was significant when compared with baseline values (for each,p < 0.05).ConclusionsP100 amplitude of the P-VEP test parallels the improvement in subjective visual acuity in amblyopic eyes under occlusion therapy. Therefore, this test may be useful in monitoring the visual acuity in the preverbal or non-verbal patched patients.

Pattern electroretinogram for monitoring the efficacy of intravitreal triamcinolone injection in diabetic macular edema

Purpose: To investigate the efficacy of intravitreal triamcinolone (IVT) by evaluation of pattern electroretinogram (PERG) in diabetic patients with clinically significant macular edema (CSME). Methods: Forty eyes of 40 diabetic patients were treated with 8 mg of IVT injection as primary therapy for CSME. The main outcome measures included best-corrected visual acuity, fundus fluorescein angiography, P50 amplitudes of pattern electroretinogram (PERG) and intraocular pressures before and after injection. Results: The mean follow-up time was 6.1 months. Mean visual acuity improved significantly from a mean LogMAR value of 1.14 ± 0.16 at baseline to a maximum of 0.73 ± 0.30. The mean baseline P50 amplitude of PERG before intravitreal injection was 1.5 ± 0.9 μV. After the treatment, it was 2.l ± 1.1 μV at 1-month, 2.4 ± 1.0 μV at 3-month and 2.1 ± 0.9 μV at last visit and the differences were significant when compared with baseline values (for each, p < 0.001). Temporary increases in intraocular pressures were controlled with topical antiglaucomatous medications, if required. Conclusion: IVT injection provides rapid improvement in visual acuity of diabetic patients with CSME that has been supported by P50 amplitudes of PERG. P50 amplitudes of PERG may be used as novel predictive value in the evaluation of the effectiveness of IVT injection.