Hüseyin Kaya

Impact of Valsalva maneuver on corneal morphology and anterior chamber parameters.

Purpose: Our aim was to examine the influence of the Valsalva maneuver (VM) on corneal morphology and anterior chamber parameters. Methods: This prospective observational study included 35 eyes of 35 healthy volunteers. One of the eyes of each subject was selected randomly. The keratometry (K), pachymetry, corneal volume, iridocorneal angle, anterior chamber depth, anterior chamber volume, and corneal wave front measurements (high-order aberration, low-order aberration, total root mean square) were performed with the Pentacam HR (Oculus, Wetzlar, Germany). Results: The subjects were aged between 22 and 41 years. There were 24 men (69%) and 11 women (31%). The VM did not have any significant influence on K-flat and K-average values (P > 0.05), but it decreased K-steep values significantly (P = 0.006). The VM did not have any significant impact on low-order aberrations and total root mean square parameters (P > 0.05), but it increased high-order aberrations significantly (P = 0.008). The central corneal thickness and corneal volume decreased significantly during the VM (P < 0.05). The iridocorneal angle, anterior chamber depth, and anterior chamber volume decreased markedly during the VM (P < 0.001). Conclusions: The VM has some influence on corneal morphology and anterior chamber parameters, so that it should be considered during anterior segment examinations and operations.

Posterior pole asymmetry analysis and retinal thickness measurements in young relatives of glaucoma patients

The presence of a family history of glaucoma is a known risk factor for primary open‐angle glaucoma (POAG) in middle‐aged and older individuals. In this study, our aim was to demonstrate possible early glaucomatous alterations in young first‐ and second‐degree relatives of POAG patients by spectral‐domain optical coherence tomography. A total of 104 participants (52 relatives of POAG patients and 52 healthy individuals) were recruited in this cross‐sectional study. All the participants were between 17 years and 45 years of age. All eyes underwent testing with spectral‐domain optical coherence tomography. Peripapillary retinal nerve fiber layer thickness, hemifield macular thickness, macular ganglion cell complex thickness, posterior pole asymmetry analysis, and retinal arteriolar caliber measurements were taken for comparison between the study and control groups. The mean peripapillary retinal nerve fiber layer thickness was 104.9 ± 8.8 μm in the study group and 105.6 ± 7.4 μm in the control group (p = 0.68). Although whole macular thickness measurements were higher in the control group when compared with the study group (p = 0.008), the macular ganglion cell complex thickness was similar in both groups (p = 0.87). The posterior pole asymmetry analysis revealed no statistically significant difference between the groups in the aspect of consecutive black squares (p = 0.79). The mean retinal arteriolar caliber was 85.9 ± 4.8 μm in the study group and 86.0 ± 5.0 μm in the control group (p = 0.90). In conclusion, young relatives of POAG patients do not show characteristic glaucomatous damage when compared with the controls.

Assessment of optic disc and ganglion cell layer in diabetes mellitus type 2

Abstract The purpose of this study was to compare the optic disc parameters, retinal nerve fiber (RNFL), and macular ganglion cell layers between patients with diabetes mellitus (DM) type 2 and healthy controls. In this cross-sectional study, 69 eyes of 69 diabetic patients without diabetic retinopathy and 47 eyes of 47 healthy controls were included. Optic disc parameters (i.e., rim area, disc area, cup to disc ratio, cup volume), RNFL, and macular ganglion cell-inner plexiform layers (GCL + IPL) thickness were measured by means of spectral domain optical coherence tomography. There were not statistically significant differences between the diabetic patients and healthy controls in terms of RNFL thickness (P = .32), rim area (P = .20), disc area (P = .16), cup volume (P = .12), and average macular GCL + IPL thickness (P = .11). Nevertheless, binocular RNFL thickness symmetry percentage (P =.03), average cup to disc ratio (P = .02), and superior-nasal macular GCL + IPL thickness (P = .04) were statistically significantly different in the diabetic and control groups. Diabetic patients without retinopathy have more binocular RNFL thickness asymmetry, higher cup to disc ratio, and thinner sectoral macular GCL + IPL when compared to healthy controls. Our results may support the statement that DM causes inner retinal neurodegenerative changes.

Relationship Between Subfoveal Choroidal Thickness, Ocular Pulse Amplitude, and Intraocular Pressure in Healthy Subjects.

Purpose:To investigate the correlation between subfoveal choroidal thickness (SFCT), ocular pulse amplitude (OPA), and intraocular pressure (IOP) in healthy individuals. Methods:In total, 106 eyes of 106 healthy adult participants were included in this cross-sectional study. Spectral-domain optical coherence tomography was used to measure the SFCT. OPA and IOP were measured with the Pascal dynamic contour tonometer. The Pearson correlation test was performed to examine the relationship between SFCT, OPA, and IOP. Results:When age, sex, and body mass index (BMI) were controlled separately, a weak correlation occurred between SFCT and OPA (age controlled, r=0.20; sex controlled, r=0.19; BMI controlled, r=0.13). SFCT and OPA were fairly correlated in older age (r=0.33, P=0.02) and low BMI (r=0.33, P=0.02). SFCT and IOP were not correlated statistically significantly (r=0.05, P=0.59). Conclusion:There is a weak correlation between SFCT and OPA in healthy individuals when age is controlled. The association becomes stronger in participants with low BMI. There is no relation between SFCT and IOP.

Effects of coronary artery bypass grafting surgery on retinal vascular caliber, ocular pulse amplitude and retinal thickness measurements

Aim: The retina and ocular vasculature are vulnerable to alterations in systemic hemodynamics, such as in open heart surgeries. Our aim was to investigate retinal vascular caliber (RVC), ocular pulse amplitude (OPA), peripapillary retinal nerve fiber layer (RNFL) and macular thickness in coronary artery bypass grafting (CABG) surgery patients. Methods: Twenty-six patients who had a history of CABG surgery and 26 age-sex-matched healthy participants were recruited for this prospective, cross-sectional and comparative study. The RVC, peripapillary RNFL and macular thickness measurements were taken with spectral-domain optical coherence tomography. The OPA, a surrogate of pulsatile ocular blood flow, was measured with the Pascal dynamic contour tonometer. Results: There were no statistically significant differences between the CABG surgery patients and the controls with regard to RVC, OPA, peripapillary RNFL thickness and macular thickness measurements (p>0.05). Conclusions: CABG surgery does not affect retinal structures and pulsatile ocular blood flow in the long-term follow-up.

Is increased choroidal thickness associated with primary angle closure

Editor, W ith great interest, we read the article ‘Is increased choroidal thickness associated with primary angle closure?’ (Zhou et al. 2014). The authors aimed to evaluate whether increased choroidal thickness is a risk factor for primary angle closure using enhanced depth optical coherence tomography in a specific Chinese population. They found that eyes with primary angleclosure glaucoma have a higher level of subfoveal choroidal thickness than normal eyes. We congratulate the authors for their excellent work. We would like to make some contributions and criticisms related to this study. Nowadays, the choroidal thickness measurement by enhanced depth optical coherence tomography is a hot topic in ophthalmology. Many studies have been reported in the literature about choroidal thickness in various physiological or disease conditions. As the choroid is utmost important for the proper functioning of outer retina, it deserves that interest. As we know, there are lots of factors that could affect subfoveal choroidal thickness such as age, axial length, ethnicity, systemic and retina–choroidal disorders, and several daily activities. These factors should be taken into consideration when conducting a study related to subfoveal choroidal thickness. It was reported that choroidal thickness decreases following cigarette smoking and coffee drinking at least for some hours (Sizmaz et al. 2013; Vural et al. 2014). Although there are not many studies related to the influence of drugs on choroid, it was found that choroidal thickness increases in response to systemic sildenafil (Kim et al. 2013). Also, there is significant diurnal variation of subfoveal choroidal thickness (Tan et al. 2012). In addition, gonioscopic examination alone and Valsalva manoeuver performed by the patient during the examinations might cause alterations in intra-ocular pressure and anterior chamber depth, and thus may affect the choroidal thickness. Finally, we wonder if the patients had undergone ocular massage as a first line treatment in the study group, because ocular massage may alter intra-ocular pressure, ocular blood flow and in turn choroidal thickness. We believe that addition of information about the above mentioned factors might help us to reach more definitive conclusions in the present study.

Does Fundus Fluorescein Angiography Procedure Affect Ocular Pulse Amplitude

Purpose. This study examines the effects of fundus fluorescein angiography (FFA) procedure on ocular pulse amplitude (OPA) and intraocular pressure (IOP). Materials and Methods. Sixty eyes of 30 nonproliferative diabetic retinopathy patients (15 males, 15 females) were included in this cross-sectional case series. IOP and OPA were measured with the Pascal dynamic contour tonometer before and after 5 minutes of intravenous fluorescein dye injection. Results. Pre-FFA mean OPA value was 3.05 ± 1.36 mmHg and post-FFA mean OPA value was 2.93 ± 1.28 mmHg (P = 0.071). Pre-FFA mean IOP value was 17.97 ± 1.99 mmHg and post-FFA mean IOP value was 17.81 ± 2.22 mmHg (P = 0.407). Conclusion. Although both mean OPA and IOP values were decreased after FFA procedure, the difference was not statistically significant. This clinical trial is registered with Australian New Zealand Clinical Trials Registry number ACTRN12613000433707.