Ahmet Tas

Color vision versus pattern visual evoked potentials in the assessment of subclinical optic pathway involvement in multiple sclerosis.

Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP) is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM) 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P100 amplitude, P100 latency in PVEP and total error scores (TES) in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7) and 4.1 ± 4.4 years. MS group showed significantly delayed P100 latency for both checks (P < 0.001). Similarly, MS patients had significantly increased total error scores (TES) in FM-100 Hue (P < 0.001). The correlations between TESs and PVEP amplitudes / latencies were insignificant for both checks (P > 0.05 for all). 14 MS patients (70%) had an increased TESs in FM-100 Hue, 11 (55%) MS patients had delayed P100 latency and 9 (45%) had reduced P100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P100 latency, and 0.173 for P100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.

Endostatin in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events and survival

BACKGROUND AND AIMS Endostatin, generated from collagen XVIII, and endorepellin, possess dual activity as modifiers of both angiogenesis and endothelial cell autophagy. Plasma endostatin levels are elevated in a large number of diseases, and may reflect endothelial cell dysfunction. Few data on endostatins are available for patients with chronic kidney disease (CKD). We tested whether serum endostatin values are predictive for all-cause mortality and cardiovascular events (CVEs) in a CKD population. MATERIALS AND METHOD A total of 519 CKD pre-dialysis patients were included. Baseline plasma endostatin levels were measured in all patients. All included patients were followed-up (time-to-event analysis) until occurrence of death, fatal or nonfatal CVEs. Fatal and nonfatal CVE including death, stroke, and myocardial infarction were recorded prospectively RESULTS The mean age of the patients was 52.2±12.3years. There were 241 (46.4%) males, 111 (21.4%) had diabetes, 229 (44.1%) were smokers and 103 (19.8%) had a previous CVE. After a median follow-up of 46months, 46 patients died and 172 had a new CVE. In the univariable Cox survival analysis, higher endostatin levels were associated with a higher risk for both outcomes. However, after adjusting for traditional (age, gender, smoking status, diabetes, systolic blood pressure, HDL and total cholesterol) and renal-specific (eGFR, proteinuria and hsCRP) risk factors, endostatin levels remained associated only with the CVE outcome (HR=1.88, 95% CI 1.37-2.41 for a 1 SD increase in log endostatin values). CONCLUSION Endostatin levels are independently associated with incident CVE in CKD patients, but show limited prediction abilities for all-cause mortality and CVE above traditional and renal-specific risk factors.

A comparative study between intravitreal triamcinolone and bevacizumab for macular edema due to central retinal vein occlusion with poor vision

Aim: To compare the effect of intravitreal bevacizumab and triamcinolone in patients with macular edema after central retinal vein occlusion (CRVO), presenting with poor visual acuity. Materials and Methods: It was a retrospective, comparative case series of 38 consecutive eyes, with macular edema secondary to CRVO, with 20/200 or worse vision, which were treated primarily either with intravitreal bevacizumab (1.25 mg; 24 eyes) or intravitreal triamcinolone (4 mg; 14 eyes). During follow-up, 3.6 ± 0.8 re-injections of bevacizumab and 2.4 ± 0.5 re-injections of triamcinolone were administered (P = 0.080). The main outcome measures were the best-corrected visual acuity and the central macular thickness by optical coherence tomography during 12 months of follow-up. Results: At 12 months, visual acuity (logMAR) was changed from 1.03 ± 0.39 (baseline) to 0.92 ± 0.39 (P = 0.374) and the central macular thickness was reduced from a baseline of 713.6 ± 179.3 μm to 310.8 ± 205.2 μm (P = 0.000). Neither the bevacizumab nor triamcinolone groups varied significantly in visual acuity and central macular thickness at 1, 3, 6, and 12 months after treatment. Neovascular glaucoma developed in two of the 14 eyes (14%) in the triamcinolone group. Conclusion: In patients with CRVO and poor vision, intravitreal bevacizumab and intravitreal triamcinolone were associated with a reduction in macular edema; however, neither treatment achieved significant visual acuity improvement by the 12-month follow-up.Aim: To compare the effect of intravitreal bevacizumab and triamcinolone in patients with macular edema after central retinal vein occlusion (CRVO), presenting with poor visual acuity. Materials and Methods: It was a retrospective, comparative case series of 38 consecutive eyes, with macular edema secondary to CRVO, with 20/200 or worse vision, which were treated primarily either with intravitreal bevacizumab (1.25 mg; 24 eyes) or intravitreal triamcinolone (4 mg; 14 eyes). During follow-up, 3.6 ± 0.8 re-injections of bevacizumab and 2.4 ± 0.5 re-injections of triamcinolone were administered (P = 0.080). The main outcome measures were the best-corrected visual acuity and the central macular thickness by optical coherence tomography during 12 months of follow-up. Results: At 12 months, visual acuity (logMAR) was changed from 1.03 ± 0.39 (baseline) to 0.92 ± 0.39 (P = 0.374) and the central macular thickness was reduced from a baseline of 713.6 ± 179.3 µm to 310.8 ± 205.2 µm (P = 0.000). Neither the bevacizumab nor triamcinolone groups varied significantly in visual acuity and central macular thickness at 1, 3, 6, and 12 months after treatment. Neovascular glaucoma developed in two of the 14 eyes (14%) in the triamcinolone group. Conclusion: In patients with CRVO and poor vision, intravitreal bevacizumab and intravitreal triamcinolone were associated with a reduction in macular edema; however, neither treatment achieved significant visual acuity improvement by the 12-month follow-up.

Detection of retinal nerve fibre layer degeneration in patients with Alzheimer's disease using optical coherence tomography: searching new biomarkers

Editor, W e congratulate Bambo et al. (Bambo et al. 2014) for their study entitled ‘Detection of retinal nerve fibre layer degeneration in patients with Alzheimer’s disease using optical coherence tomography: searching new biomarkers’. The authors compared retinal nerve fibre layer (RNFL) thickness differences between patients with Alzheimer’s disease and healthy controls using the two most commonly available spectral-domain optical coherence tomography (SD-OCT) machines. The authors found significant thinning in superior and inferior RNFL in Cirrus OCT (Carl Zeiss, Meditec, Inc., Dublin, Ireland) and significant thinning in the inferior and infero-temporal RNFL in Spectralis OCT (Heidelberg Engineering, Inc., Carlsbad, CA, USA). The authors also stated that they included the visual acuity and colour vision examinations of the patients. Previously, we studied whether RNFL thickness may be used as a biomarker in the early diagnosis of multiple sclerosis (Gundogan et al. 2007). We found that a clinical finding – colour vision assessment – is better correlated with the disease activity. At this point, we want to ask to the authors to perform a correlation analysis between the visual acuity, colour vision, RNFL thickness and the clinical stage of the Alzheimer’s disease activity to explore which parameter is best-correlated with the disease severity.

Electroretinogram in Hereditary Retinal Disorders

Electroretinogram (ERG) represents the electrical response of retina to a light stimulus. The light stimuli may be either a pattern (spatially structured) stimulus or a flash (unstructured) stimulus, and the retina may be stimulated completely or partially. In this chapter, we will briefly mention about the recording procedures of electroretinographic tests. Electroretinographic testing procedures and findings in hereditary retinal dystrophies will be discussed from a clinical point of view.

Retinal pathology in multiple sclerosis: insight into the mechanisms of neuronal pathology

Sir, We congratulate Calabresi et al . (2010) for the scientific commentary regarding retinal pathology in multiple sclerosis. The authors have excellently summarized the pathological mechanism in multiple sclerosis in the brain and retina. We would like to make a contribution to the retinal aspects of their comments. Full-field flash electroretinogram is the mass electrical activity of the retina to a flash of light. Pattern electroretinogram reflects the retinal response to a structured, contrast-reversal stimulus, mostly a checkerboard pattern. There have been many studies investigating the functional and structural retinal changes in the retinas of patients with multiple sclerosis. Mostly, optical coherence tomography has been used to explore the structural changes that show retinal nerve fibre layer thinning. This change was …

Efficacy of Latanoprost Additive Therapy on Uncontrolled Glaucoma

Purpose: To assess the efficacy of latanoprost as additive therapy in patients with open-angle glaucoma and an intraocular pressure (IOP) deemed to be too high on maximum tolerated medical therapy. Study Design: Prospective case series. Methods: Consecutive patients with open-angle glaucoma, presenting to the Gulhane Military Medical Hospital Ophthalmology Clinic from May 1999 to September 2000 were enrolled. The effect of latanoprost on IOP was followed during a period of 12 months. The criterion for success was defined as having an IOP reduction of at least 20% from baseline or a final IOP of less than 22 mm Hg. Several clinical pretreatment variables (age, gender, ocular laterality, type of glaucoma, number of antiglaucomatous medications at study entry, pretreatment IOP) were analyzed for a significant effect on the efficacy of latanoprost additive therapy. Main Outcome Measure: IOP. Results: Sixty-five eyes of 35 patients were included. The mean baseline IOP ± SD was 23.3 ± 2.0 mm Hg. Two patients (5.71%) developed ocular allergy in the first month requiring cessation of latanoprost. In the remaining 61 eyes of 33 patients, IOP was significantly reduced compared with baseline measurements with a mean IOP reduction of 6.1 ± 1.8 (26.1%), 6.0 ± 2.2 (25.3%) and 5.5 ± 2.4 (23.2%) mm Hg at the 1-, 3- and 6-month follow-up controls, respectively (p < 0.001). Successful outcome was obtained in 50 (76.9%), 46 (70.7%) and 38 (58.4%) of 65 eyes at the 1-, 3- and 6-month visits, respectively. During the period from 6 to 12 months, 28 eyes underwent either a combined procedure (cataract extraction + intraocular lens implantation + trabeculectomy; 8 eyes) or only trabeculectomy (20 eyes) because of uncontrolled IOP; 4 eyes underwent the combined procedure because of visually significant cataract, and 8 eyes were lost to follow-up. Sixteen out of 21 eyes followed for more than 12 months with the same medications continued to have a successful outcome, and the mean IOP of 18.8 ± 3.7 mm Hg was significantly different from baseline (p < 0.001). None of the pretreatment variables was a significant prognostic factor for failure of latanoprost additive therapy. Conclusion: This study supports the use of latanoprost additive therapy in patients with elevated IOP already receiving maximum-tolerated medical therapy.

Polycystic Ovary Syndrome and Increased Soluble Tumor Necrosis Factor Like Weak Inducer of Apoptosis Levels Are Independent Predictors of Dyslipidemia in Youth

Background/Aims: Dyslipidemia is common in women with polycystic ovary syndrome (PCOS) irrespective of age. Our aim was to investigate soluble tumor necrosis factor like weak inducer of apoptosis (sTWEAK), a cardiovascular risk marker in PCOS, and to determine if it is associated with dyslipidemia in youth. Methods: A prospective-observational study was carried out including 35 PCOS patients and 35 healthy controls. Serum sTWEAK levels were measured using commercially available kits. Multiple logistic regression analysis was then performed to verify the statistically significant differences in the possible predictors of dyslipidemia. Results: Serum sTWEAK levels and the percentage of women with dyslipidemia were significantly higher in the PCOS group (p = 0.024 and p < 0.001, respectively). Participants were further divided into 2 subgroups based on the presence of dyslipidemia. The percentage of women with PCOS was significantly higher in the dyslipidemic group when compared with controls; 70.7 vs. 20.7%, respectively (p < 0.001). Multiple logistic regression analysis revealed that both the presence of PCOS (OR 7.924, 95% CI 2.117-29.657, p = 0.002) and increased levels of sTWEAK (>693 pg/ml; OR 3.810, 95% CI 1.075-13.501, p = 0.038) were independently associated with dyslipidemia. Conclusions: Increased levels of both sTWEAK and PCOS were found to be independently associated with dyslipidemia in youth.

Pharmacotherapy for treatment of retinal vein occlusion

We congratulate Sarao et al. for their article entitled ‘Pharmacotherapy For Treatment Of Retinal Vein Occlusion (RVO)’ [1]. The authors presented an update and a brief review on the current treatment modalities and promising alternatives for RVO. We would like to mention about matrix metalloproteinase (MMP)-9 as a potential future target. MMP-9 is involved in the breakdown and re-modeling of extracellular matrix in multiple physiological and pathological processes such as angiogenesis, wound healing, cell migration, and etc. Studies about the role of MMP-9 in retinal vascular disorders are few. It has been demonstrated that MMP-2 and MMP-9 may trigger apoptosis of retinal capillary cells, mitochondrial dysfunction and neovascularization in diabetic retinopathy. Grieshaber et al. revealed the role of MMP-9 to optic disc and peripapillary retinal hemorrhages [2]. In ischemic stroke or intracerebral hemorrhage, there is an extensive expression of MMP-9 that is related to excitotoxicity, apoptosis, neural damage, hemorrhagic transformation and blood-brain barrier disruption that results in tissue edema. We hypothesize that MMP-9 may be a possible cause of retinal edema similar to stroke. Bertelmann et al. have demonstrated the elevation of intravitreal functional plasminogen in eyes with central and branch RVO and correlated with the extent of blood--retina barrier damage [3]. This pathological process could be mediated by MMP-9 similar to stroke. Meanwhile, Tuuminen et al. recently found that intravitreal levels of MMP-9 is significantly elevated in patients with RVO patients [4]. In regard to data mentioned above, we assume that MMP-9 can be considered as a rational target for RVO treatment. The inhibition of MMP-9 interfere with degradation of basement membrane and related intimal hyperplasia. This inhibition contributes in the prevention of vascular stenosis [5]. So targeting MMP-9 may be protective as well.

Re: A prospective observational study of techniques to remove corneal foreign body in the emergency department

Dear Editor, We have read the article entitled ‘A prospective observational study of techniques to remove corneal foreign body in the emergency department.’ by Quirke et al 1 with interest. We congratulate the authors that they called attention to an important issue in the emergency settings. The study aimed to compare the slit-lamp-aided technique of superficial corneal foreign body (FB) removal with direct removal without the aid of a slit-lamp biomicroscopy performed by emergency physicians. In …