Harun Yüksel

Comparison of accelerated and conventional corneal collagen cross-linking for progressive keratoconus

Abstract Purpose: To compare outcomes of accelerated and conventional corneal cross-linking (CXL) for progressive keratoconus (KC). Materials and methods: Patients were divided into two groups as the accelerated CXL group and the conventional CXL group. The uncorrected distant visual acuity (UDVA), corrected distant visual acuity (CDVA), refraction and keratometric values were measured preoperatively and postoperatively. The data of the two groups were compared statistically. Results: The mean UDVA and CDVA were better at the six month postoperative when compared with preoperative values in two groups. While change in UDVA and CDVA was statistically significant in the accelerated CXL group (pu2009=u20090.035 and pu2009=u20090.047, respectively), it did not reach statistical significance in the conventional CXL group (pu2009=u20090.184 and pu2009=u20090.113, respectively). The decrease in the mean corneal power (Km) and maximum keratometric value (Kmax) were statistically significant in both groups (pu2009=u20090.012 and 0.046, respectively in the accelerated CXL group, pu2009=u20090.012 and 0.041, respectively, in the conventional CXL group). There was no statistically significant difference in visual and refractive results between the two groups (pu2009>u20090.05). Conclusions: Refractive and visual results of the accelerated CXL method and the conventional CXL method for the treatment of KC in short time period were similar. The accelerated CXL method faster and provide high throughput of the patients.

Accelerated corneal collagen cross-linking for progressive keratoconus

Abstract Purpose: To evaluate the efficacy of accelerated corneal cross-linking (CXL) procedure for progressive keratoconus. Materials and methods: Twenty-three eyes of 23 patients undergone accelerated CXL procedure were evaluated preoperatively and postoperatively at 1st, 3rd and 6th month for uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (CDVA), spherical error, cylindrical error, spherical equivalent (SE), keratometric values and thinnest corneal thickness (TCT) values with corneal topography by Scheimpflug camera and endothelial cell density (ECD). Results: The mean UDVA was improved from 0.97u2009±u20090.41 logarithm of minimal angle of resolution (logMAR) to 0.76u2009±u20090.45 logMAR at the 6th month after CXL (pu2009=u20090.332). The mean CDVA was improved from 0.49u2009±u20090.30 logMAR to 0.34u2009±u20090.22 logMAR at the 6th month after CXL (pu2009=u20090.026). The mean sphere was decreased from −4.47u2009±u20094.1 diopter (D) to −3.79u2009±u20093.86u2009D and the mean cylinder was decreased from −5.60u2009±u20092.2u2009D to −4.55u2009±u20091.98u2009D and the mean SE was decreased from −7.22u2009±u20094.48u2009D to −6.36u2009±u20094.34u2009D at the 6th month after CXL (pu2009=u20090.128, pu2009=u20090.002 and pu2009=u20090.045, respectively). Flat keratometry, steep keratometry, mean keratometry and maximum keratometry were significantly reduced at the 6th month after CXL (pu2009=u20090.025, pu2009<u20090.001, pu2009=u20090.004 and pu2009=u20090.03, respectively). TCT and ECD were not changed significantly the 6th month after CXL (pu2009=u20090.135 and pu2009=u20090.082, respectively). Conclusion: Accelerated CXL procedure was effective to stabilize progression of keratoconus with significant reduction in topographic keratometric values and significant increase in CDVA in 6 months.

Transient corneal endothelial changes following accelerated collagen cross-linking for the treatment of progressive keratoconus

Abstract Purpose: To evaluate the corneal endothelial changes following accelerated collagen cross-linking (CXL) for the treatment of progressive keratoconus. Methods: Thirty-six consecutive progressive keratoconus patients who received accelerated CXL treatment were enrolled in the study. Following de-epithelization, isoosmolar 0.1% riboflavin solution without dextran was instilled every 3u2009min throughout the 30u2009min of soaking time before the 5u2009min of 18u2009mW/cm2 UVA irradiation and every 2u2009min during the UVA irradiation. Corneal specular microscopy was performed on both treated and fellow eyes of each patient preoperatively, in the first week, and in the first, third and sixth month postoperatively. Results: There were significant differences in endothelial cell density (ECD), percentages of hexagonality (6A) and coefficient of variation of endothelial cell area (CV) in the first week and first month postoperatively in the treated eyes when compared to their preoperative values and also to the first week and first month ECD, 6A and CV values of the non-operative eyes. ECD returned to the preoperative values at sixth month whereas 6A and CV returned to the preoperative values at third month. Conclusion: Our results suggested that there may be transient changes in human corneal endothelium following accelerated UVA/riboflavin CXL.u2009Resolution of these changes during the follow-up may indicate a safe recovery. However, the treatment guidelines for accelerated CXL including irradiance level and soaking time should be clearly established to minimize the toxic effects of the treatment.

Intravitreal bevacizumab monotherapy for retinopathy of prematurity.

The aim of this study was to evaluate the treatment outcomes of intravitreal bevacizumab (IVB) injections, used as a monotherapy in type 1 retinopathy of prematurity (ROP).

The Mean Platelet Volume in Patients with Retinal Vein Occlusion

Background. The aim of this study was to investigate the mean platelet volume (MPV) of patients with retinal vein occlusion (RVO). Methods. Hundred and ninty-three patients with the diagnosis of RVO and 83 healthy control subjects were included in this retrospective study. Retinal vein occlusion was diagnosed based on clinical examination. All patients and control subjects underwent complete ocular examination. MPV, hematocrit, hemoglobin, and platelet count of the participants were recorded. The data of patients with RVO was compared with the control subjects. Results. Patients with RVO had significantly higher MPV values (8.19 ± 1.22u2009fL) compared with the control subjects (7.68 ± 1.11u2009fL) (P = 0.004). No significant difference was found in platelet counts between RVO group and the control group (275.77 ± 70.87u2009109/L and 261.96 ± 59.40u2009109/L, resp., P = 0.161), Mean platelet volume was an independent predictor of RVO (odds ratio (OR) = 1.43; 95% confidence interval (CI) = 1.09–1.89; P = 0.011). Conclusion. Our results demonstrated that the MPV values were significantly higher in patients with RVO, suggesting that larger platelets may contribute to the pathogenesis of the RVOs.

The protective effects of caffeic acid phenethyl ester in isoniazid and ethambutol-induced ocular toxicity of rats

Abstract Purpose: This study intended to examine the effect of caffeic acid phenethyl ester (CAPE) on isoniazid (INH) and/or ethambutol (ETM)-induced retina and optic nerve toxicity in a rat model. Methods: This study included eight groups, each containing 10 rats. The groups were Control, INH, ETM, CAPE, INH+CAPE, ETM+CAPE, INH+ETM and INH+ETM+CAPE. Rats were given orally 50u2009mg/kg/d of INH and 50u2009mg/kg/d of ETM in tap water for 30u2009d. 10u2009μmol/kg of CAPE were intraperitoneally injected for 30u2009d. The first dose of CAPE was given 24u2009h before the INH and ETM treatment and continued until sacrifice. Control group was given only tap water for 30u2009d. Rats were anaesthetized and sacrificed on the 30th day of experiment. Superoxide dismutase (SOD) activities, malondialdehyde (MDA), total anti-oxidant status (TAS), total oxidant status (TOS) were measured on the dissected and excised retina and optic nerve samples. Fellow eyes were used for histopathologic evaluation and the retinal ganglion cell (RGC) count. In addition, CAPE, INH and ETM interaction with SOD isoforms were calculated in silico. Results: The SOD activity and TAS levels were found significantly higher in CAPE-treated groups compared to INH and/or ETM-treated groups (pu2009<u20090.0001). But the MDA, and TOS levels were significantly lower in CAPE-treated groups (pu2009<u20090.0001). The mean RGC count is significantly decreased in INH, ETM and INH+ETM groups compared with INH+CAPE, ETM+CAPE and INH+ETM+CAPE groups, respectively (p values 0.001, 0.042, and 0.001 respectively). Besides, in silico calculations showed that binding affinity of CAPE to SOD isotypes was higher than that of INH and ETM. Conclusion: This study demonstrates that CAPE treatment may decrease the oxidative stress in the retina and optic nerve of INH- and ETM-treated rats and may prevent RGC loss. As an underlying mechanism, CAPE and SOD interaction seems crucial for alleviation of ocular oxidative stress and RGCs toxicity.

Serum dehydroepiandrosterone sulphate, total antioxidant capacity, and total oxidant status in central serous chorioretinopathy

BackgroundThe objective of this work is to evaluate plasma total antioxidant capacity (TAC), total oxidant status (TOS), and dehydroepiandrosterone sulphate (DHEA-S) levels in patients diagnosed with acute central serous chorioretinopathy (CSCR) and control samples.MethodsThe TAC, TOS, and DHEA-S levels were assessed in the plasma of 46 CSCR patients and compared with 40 control samples.ResultsThe TAC level was 1.16u2009±u20090.08 and 1.20u2009±u20090.09xa0mmol Trolox eq./l; TOS level was 28.77u2009±u200933.33 and 19.95u2009±u200910.42xa0μmolxa0H202/l; DHEA-S level was 203.79u2009±u200984.75xa0μg/dl and 249.36u2009±u2009122.93xa0μg/dl in the CSCR group and in the control group, respectively. The plasma TAC and DHEA-S values were significantly lower in the CSCR group than in the control group (pu2009=u20090.027 and pu2009=u20090.046, respectively). There was no significant difference between the CSCR and the control groups in terms of age, gender, and TOS levels (pu2009>u20090.05).ConclusionsWe demonstrated that the levels of plasma DHEA-S and antioxidative parameters were reduced in CSCR. Our results suggest that the antioxidant defense system may be inadequate or corrupted in CSCR. Reduced DHEA-S level is one of the factors that trigger this insufficiency.

Mean Platelet Volume in Ocular Behçet’s Disease

Objective. To determine whether mean platelet volume (MPV) is an indicator of disease severity in ocular Behçets Disease (BD). Materials and Methods. The study population was 30 newly diagnosed ocular BD patients who presented with active uveitis. These patients had no past history of smoking, drug use, or systemic diseases including diabetes mellitus, hypertension, cardiovascular disease, and renal disease. A control group consisting of 34 healthy individuals was included for comparison. MPV measurements were performed serially upon presentation with active uveitis and at one and three month thereafter in BD group whereas only at presentation in the controls. Results. Upon presentation with active uveitis, the mean MPV levels were 7.88 ± 1.14 femtoliters (fL) for BD group. During the posttreatment follow-up period at first and third months, BD patients demonstrated a mean MPV level of 7.71 ± 1.12u2009fL and 7.65 ± 1.04u2009fL, respectively. The mean MPV value of control group, was 8.39 ± 0.66u2009fL at presentation. Fluctuations in MPV values were not significant in the BD group, while there was a significant difference between the initial measurements of the BD and control groups. Conclusion. MPV measurement in ocular BD is not a predictive laboratory test to determine the clinical improvement in early stages following classical immunosuppressive treatment.

Anterior segment parameters of rabbits with rotating Scheimpflug camera

BACKGROUNDnRabbit is one of the most commonly used experimental animals for corneal studies due to similarity of size to human cornea and ease of manipulation. In this study, we assessed anterior segment parameters of the healthy rabbit eyes with Pentacam HR (Oculus, Wetzlar, Germany).nnnMETHODSnSix-month-old, approximately 2.5-3 kg weighted, 30 female New Zealand rabbits were used in the study. Right eye of the each rabbit was imaged with Pentacam HR under intramuscular ketamine hydrochloride (Ketalar; Eczacibasi, Turkey) anesthesia (50 mg/kg). After the imaging, the rabbits with blinking errors, which results in low-quality images, were excluded from the study. Keratometric readings, central corneal thickness (CCT), anterior chamber depth (ACD), and anterior and posterior elevation values, and lens density were noted.nnnRESULTSnIn this study, the flattest and the steepest keratometric values were found as 43.34 ± 1.86, 42.7 ± 2.0, and 43.9 ± 1.9 diopters, respectively. The mean CCT and ACD of rabbits were found as 388 ± 39 μm and 2.08 ± 0.16 mm, respectively. Mean of the anterior and posterior elevation at thinnest point was found as 1.29 ± 4.28 and 3.91 ± 6.17 μm, respectively.nnnCONCLUSIONSnKeratometric readings and anterior and posterior elevation values of rabbits were similar to human; however, corneal thickness and anterior chamber depth (ACD) values were lower than humans.

Mean platelet volume in pseudoexfoliation syndrome and glaucoma.

Purpose Pseudoexfoliation (PEX) syndrome (PES) is characterized by the widespread deposition of abnormal extracellular fibrillary material on many ocular and extraocular tissues. The objective of this study was to evaluate the association among PES, PEX glaucoma (PEG), and mean platelet volume (MPV). Methods Forty patients with PES (mean age 62.6 ± 7.8 years), 31 with PEG (mean age 65.9 ± 6.6 years), and 37 healthy individuals (control group) (mean age 64.0 ± 7.1 years) were included in the study. The MPV of the 3 groups were compared. Results Age and sex distribution were similar among groups (p>0.05). Mean MPV in PES, PEG, and control groups were 9.59 ± 0.94 fl, 9.53 ± 0.80 fl, and 7.7 ± 0.67 fl, respectively. In the PEX group, MPV values were significantly higher than in the control group (p<0.05). However, there was no difference between the PES and PEG groups (p>0.05). Conclusions The MPV values in both groups with PEX were higher than those in the healthy group.