Mustafa Koç

Neurochemistry of the hippocampus in patients with obsessive–compulsive disorder

Aim:  To date, despite possible neuroanatomical importance, no magnetic resonance spectroscopy (MRS) study on hippocampus has been performed in obsessive–compulsive disorder (OCD). The purpose of the present study was therefore to compare hippocampal chemicals in patients with OCD with those in healthy subjects with no psychopathology.

Quantitative evaluation of early retinal changes in children with type 1 diabetes mellitus without retinopathy: Posterior segment in type 1 diabetes Tekin, Inanc, Kurnaz et al.

To investigate whether abnormal glucose metabolism and duration of diabetes mellitus (DM) caused the thinning in retinal layers in children with type 1 DM without retinopathy by using spectral domain optical coherence tomography (SD‐OCT) and to compare the results obtained with those in healthy children.

Neonate with meroacrania: radiological findings and review of the literature.

Acrania is a developmental abnormality characterized by a partial or complete absence of calvaria with complete but abnormal development of brain tissue. Acrania is a relatively common malformation and affects about 1 in 1000 newborns. Meroacrania refers to absence of the cranium with the exception of the occipital bone. Brain stem and cerebellum develop normally, but cerebral parenchyma tissue is covered with a thin membrane and severely dysmorphic supratentorial brain is also seen. The other system findings are normal. Magnetic resonance imaging findings of one neonate with meroacrania have been reported in medical literature. Other radiographic and computed tomography findings have not yet been reported. We report a female neonate with meroacrania with discussion of etiology, pathogenesis, radiological findings, and differential diagnosis.

The Effect of Pterygium and Pterygium Surgery on Corneal Biomechanics

ABSTRACT Purpose: To evaluate the effect of pterygium and pterygium surgery on corneal biomechanics by ocular response analyzer (ORA, Reichert, USA). Methods: This study considered 68 eyes (from 34 patients with a mean age of 21.2±7.1 years) with unilateral nasal, primary pterygium (horizontal length <4 mm), and having undergone pterygium excision and conjunctival autografting. Pterygium length and area were measured from a photograph of the anterior segment using Image J program. ORA measurements were obtained before surgery and after the first month of the surgery. The measurements of the eyes with pterygium and healthy eyes were compared to evaluate the effect of pterygium. Similarly, measurements obtained before and after surgery were compared to evaluate the effect of pterygium surgery on corneal biomechanics. The correlation of the ORA measurements with the pterygium area was evaluated. Results: Mean pterygium horizontal length and area were 3.31±1.43 mm and 6.82±2.17 mm2, respectively. There was no statistically significant difference between the eyes with and without pterygium in corneal hysteresis (CH, p=0.442), corneal resistance factor (CRF, p=0.554), corneal-compensated intraocular pressure (IOPcc, p=0.906), and Goldmann-correlated IOP (IOPg, p=0.836). All preoperative parameters decreased after surgery; however, none of them were statistically significant (CH, p=0.688; CRF, p=0.197; IOPcc, p=0.503; IOPg, p=0.231). There were no correlations between pterygium area and ORA measurements (p>0.05). Conclusion: Pterygium <4 mm and its surgical excision did not affect corneal biomechanics. These results may be taken into account when cornea biomechanics, mainly intraocular pressure measurements, are important.

Accelerated Corneal Cross-Linking With a Hypoosmolar Riboflavin Solution in Keratoconic Thin Corneas: Short-Term Results.

Purpose: The aim of this study was to evaluate the early term topographic and aberration results of accelerated (9 mW/cm2) corneal cross-linking (CXL) treatment in keratoconic thin corneas. Methods: Forty-nine eyes from 43 patients (mean age of 21.2 ± 7.1) with progressive keratoconic thin corneas (<400 &mgr;m without epithelium) who had accelerated corneal CXL with hypoosmolar riboflavin solution throughout the procedure were enrolled. We measured the uncorrected and corrected distance visual acuity, refraction, slit-lamp examination, topographic values, and corneal higher-order aberrations (Pentacam HR, Oculus Optikgeräte GmbH) preoperatively and 1, 3, and 6 months after surgery. Results: Before surgery, the corneal thickness was 404 ± 18 &mgr;m, and the thickness was reduced to 360 ± 24 &mgr;m after removing the epithelium. After the application of hypoosmolar riboflavin solution, the thickness increased to 432 ± 44 &mgr;m. At month 6, there was a significant increase in uncorrected distance visual acuity (P = 0.043) and corrected distance visual acuity (P = 0.024), a decrease in spherical refraction (P = 0.041), maximum keratometry (Kmax, P = 0.003), anterior elevation values (P = 0.008), corneal thickness (P < 0.001), coma (P = 0.022), spherical aberration (P = 0.001), higher-order root mean square (P = 0.004), and total root mean square (P < 0.001), whereas the cylindrical refraction (P = 0.627), anterior (P = 0.665) and posterior astigmatism (P = 0.165) of the cornea, posterior elevation (P = 0.198), and trefoil (P = 0.141) remained unchanged. No patients showed any complications or scar formation during follow-up. Conclusions: Accelerated corneal CXL with hypoosmolar riboflavin solution throughout the procedure is effective in thin corneas.

Neutrophil to Platelet Ratio in Patients with Chalazia: A Novel Marker of Local Inflammation?

Aim: To evaluate the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-platelet ratio (NPR) in patients with chalazia and to compare the data with those of healthy subjects. Materials & Methods: The preoperative complete blood count records of 200 patients who underwent chalazia surgery (study group) and 200 age-matched patients who underwent strabismus surgery (control group) in a tertiary care hospital were reviewed retrospectively. The NLR, PLR, and NPR were calculated and compared between the groups with an independent t-test. Results: The mean age in the study and control groups was 34.04 ± 16.04 and 33.91 ± 15.11 years, respectively (p = 0.934). There was no significant between-group difference in terms of NLR and PLR (p = 0.559 and p = 0.403, respectively). The mean NPR was significantly lower in the study group compared with the control group (p = 0.008). Conclusions: This study demonstrated that a lower NPR was associated with chalazion development. The NPR may be a predictive marker in local inflammatory diseases.

Decentration and Tilt of Intraocular Lens after Posterior Capsulotomy

ABSTRACT Purpose: To assess the effect of posterior capsular opacification (PCO) and Neodymium-doped:Yttrium Aluminium Garnet (Nd:YAG) laser capsulotomy on tilt and decentration of intraocular lens (IOL) at vertical and horizontal meridians. Methods: The study included 64 eyes of 64 patients. IOL decentration and tilt were measured using a Scheimpflug camera before and 1 month after Nd:YAG capsulotomy. Corrected distance visual acuity (CDVA) and manifest refraction were also determined. Between-group differences of IOL position change and the effect of Nd:YAG laser capsulotomy were analyzed. Results: In the PCO group, before capsulotomy, CDVA was significantly lower than that after capsulotomy and of the control group values (p = 0.001 for both). No significant difference was observed in CDVA between the control group and the PCO group after capsulotomy (p = 0.854). Before capsulotomy, the angle of tilt and decentration at both meridians was significantly higher than that in the control group (tilt: p < 0.001; for both decentrations: p = 0.001, p = 0.003, respectively). A significant decrease was observed in the angle of tilt at both meridians (horizontal p = 0.001, vertical p = 0.001) from before to after capsulotomy in the PCO group. Although decentration was increased after capsulotomy, no significant position change was observed (horizontal p = 0.350, vertical p = 0.107). The angle of tilt and decentration at both meridians was significantly higher in the PCO group after capsulotomy compared to the control group (p < 0.001 for all). Conclusions: PCO is associated with not only axial displacement, but also tilt and decentration of IOL at the vertical and horizontal meridians. Laser capsulotomy decreased IOL tilt but had no effect on decentration. However, these changes did not significantly change the visual acuity between the control group and the PCO group after capsulotomy.

Anterior Segment Changes during Accommodation in Accommodative Esotropia

Purpose To evaluate the anterior segment biometric parameters of non-accommodative and accommodative refractive accommodative esotropia (RAE). Methods Eighty-one eyes of 81 patients were included in this prospective, case-control study. The patients were divided into three groups as follows: the RAE group (n = 31), the hypermetropia group (n = 25), and the emmetropia group (n = 25). Measurements were obtained in the non-accommodative (0.0 diopters) and accommodative status (-5.0 diopters) using a Pentacam HR. The anterior chamber depth (ACD), anterior chamber volume (ACV), pupil diameter (PD), and anterior chamber angle (ACA) were evaluated at all four quadrants. Results The ACD, ACV and PD values in the RAE group were lower than those of the other groups in both states (p < 0.05). The ACD values were lower in the hypermetropia group than in the emmetropia group for the non-accommodative status (p = 0.024) but were similar for the accommodative status (p = 0.225). PD and ACV values were lower in the hypermetropia group than in the emmetropia group in both states (non-accommodative status, p = 0.011 and p = 0.022; accommodative status, p = 0.026 and p = 0.034, respectively). Changes in ACD, ACV and PD during accommodation (Δ) were not significant in the RAE group but were significant for the other groups (hypermetropia: ΔACD, p = 0.001; ΔACV, p = 0.001; ΔPD, p = 0.002; emmetropia: ΔACD, p < 0.001; ΔACV, p = 0.001; ΔPD, p < 0.001). These changes were significantly lower in the hypermetropia group than in the emmetropia group (ΔACD, p = 0.012; ΔACV, p = 0.031; ΔPD, p = 0.034). Conclusions The anterior chamber in RAE patients was shallower and the increase in convexity of the anterior surface or forward movement of the crystalline lens was more limited during accommodation in RAE.

The effect of corneal infiltrates on densitometry and higher-order aberrations: Densitometry and aberrometry on infiltrates

This study aimed to measure the effects of persistent corneal subepithelial infiltrates associated with epidemic keratoconjunctivitis on corneal densitometry and total corneal higher order aberrations (HOAs), and to compare these measurements with the data obtained from their fellow unaffected healthy eyes.

Re: The factors influencing retinal thickness in diabetic patients: Posterior segment evaluation in Type 1 DM

EDITOR: We read with great interest the article entitled ‘Quantitative evaluation of early retinal changes in children with type 1 diabetes mellitus without retinopathy’ by Tekin et al. The authors analysed the alterations of macula and peripapillary retinal nerve fibre layer thickness in patients with type 1 diabetes without diabetic retinopathy using spectral domain optical coherence tomography. They reported significantly lower mean values of the temporal inner, temporal outer and inferior outer macular thickness measurements in type 1 diabetic subjects compared to those of controls. Moreover, the children with type 1 diabetes mellitus had significantly thinner global, temporal superior and nasal inferior retinal nerve fibre layer thickness measurements compared to the controls. We congratulate the authors for their study. However, we have some comments with regard to this publication. Several local and some systemic conditions have been previously reported to affect retinal nerve fibre layer and macular thickness. First, retinal nerve fibre layer and macular thickness may differ according to axial length. The authors reported that the eyes with spherical power less than 1.00 D were included; however, if they had taken axial length and spherical equivalent into account, this might strengthen the study results. Second, it has been reported that children with obesity and/or increased body mass index had a thinner retinal nerve fibre layer and that there is a negative correlation between retinal nerve fibre layer thickness and body mass index. Moreover, the presence of hyperlipidaemia can cause alterations in the retinal nerve fibre layer. Thirdly, although it was mentioned that the patients with glaucoma were excluded, intraocular pressure and central corneal thickness are important factors to consider when evaluating retinal nerve fibre layer thickness differences. Recently Carlo et al. reported that optical coherence tomography angiography is able to detect foveal microvascular changes which clinical examination cannot reveal in diabetic eyes. Hence, the presence of invasive or non-invasive angiography might strengthen their work. Finally, as Tekin et al. mentioned in the limitations of the study, ganglion cell thickness evaluation is important in such study design, since neurodegeneration may present even without clinical retinopathy in the diabetic population. We hope our comments will contribute to improvement in future research on diabetic retinopathy.