Gokhan Ozge

Corneal biomechanical changes in diabetes mellitus and their influence on intraocular pressure measurements.

PURPOSE To investigate possible corneal biomechanical changes in patients with diabetes mellitus and understand the influence of such changes on intraocular pressure measurements. METHODS The study group was composed of 120 eyes from 61 healthy control subjects and 81 eyes from 43 diabetic subjects. IOP was measured first with an ocular response analyzer (ORA) and subsequently with a Goldmann applanation tonometer (GAT). Central corneal thickness (CCT) was measured with an ultrasonic pachymeter attached to the ORA. Axial length (AL), anterior chamber depth (ACD), and keratometry readings were acquired with partial coherence laser interferometry during the same visit before all IOP and CCT determinations were made. RESULTS Corneal hysteresis (CH) was found to be significantly lower in diabetic patients when compared with healthy control subjects (9.51 +/- 1.82 mm Hg vs. 10.41 +/- 1.66 mm Hg, P < 0.0001). There was no significant difference in terms of corneal resistance factor (CRF; P = 0.8). Mean CCT, GAT IOP, Goldmann-correlated IOP (IOPg), and corneal-compensated IOP (IOPcc) were significantly higher in diabetic patients than in healthy control subjects (P = 0.01 for CCT, P < 0.0001 for GAT IOP, IOPg, and IOPcc). CONCLUSIONS Diabetes affects corneal biomechanics and results in lower CH values than those in healthy control subjects, which may cause clinically relevant high IOP measurements independent of CCT.

Intraocular pressure values obtained by ocular response analyzer, dynamic contour tonometry, and goldmann tonometry in keratokonic corneas.

PurposeTo determine the agreement between dynamic contour tonometer (DCT), Goldmann applanation tonometer (GAT), and Ocular Response Analyzer (ORA) in keratoconic corneas and to find out the effect of corneal biomechanics on intraocular pressure (IOP) measurements obtained by these devices. Subjects and MethodsIOP was measured with the ORA, DCT, and GAT in random order in 120 eyes of 61 keratoconus patients. Central corneal thickness (CCT) and keratometry were measured after all IOP determinations had been made. The mean IOP measurement by the ORA and DCT was compared with the measurement by the GAT, using Student t test. Bland-Altman analysis was performed to assess the clinical agreement between these methods. The effect of corneal hysteresis (CH), corneal resistance factor (CRF), and CCT on measured IOP was explored by multiple backward stepwise linear regression analysis. ResultsThe mean±SD patient age was 30.6±11.2 years. The mean±SD IOP measurement obtained with GAT, ORA Goldmann-correlated IOP (IOPg), ORA corneal-compensated IOP (IOPcc), and DCT was 10.96±2.8, 10.23±3.5, 14.65±2.8, and 15.42±2.7 mm Hg, respectively. The mean±SD CCT was 464.08±58.4 microns. The mean difference between IOPcc and GAT (P<0.0001), IOPcc and DCT (P<0.001), GAT and DCT (P<0.0001), IOPg and GAT (P<0.002), and IOPg and DCT (P<0.0001), was highly statistically significant. In multivariable regression analysis, DCT IOP and GAT IOP measurements were significantly associated with CH and CRF (P<0.0001 for both). ConclusionsDCT seemed to be affected by CH and CRF, and the IOP values tended to be higher when compared with GAT. ORA-measured IOPcc was found to be independent of CCT and suitable in comparison to the DCT in keratoconic eyes.

Effects of multiple intravitreal anti-VEGF injections on retinal nerve fiber layer and intraocular pressure:a comparative clinical study

AIM To determine the effect of multiple injections of ranibizumab or bevacizumab on retinal nerve fiber layer (RNFL) and intraocular pressure (IOP) in patients with age-related macular degeneration (AMD). METHODS This retrospective study includes 35 eyes of 35 patients treated with intravitreal bevacizumab (IVB, 1.25mg/0.05mL) and 30 eyes of 30 patients with intravitreal ranibizumab (IVR, 0.5mg/0.05mL) who had Fast RNFL analysis (Stratus™); IOP measurements were taken 30 minutes and 24 hours after each injection. RESULTS The mean ages were 68.0±7.5 and 69.1±7.7 years in the IVR and IVB groups, respectively (P=0.55). They underwent (6.3±1.9) and (5.1±1.3) injections (P=0.07) over (13.6±2.1) and (14.05±2.6) months (P=0.45) in the IVR and IVB groups, respectively. Changes in overall and temporal RNFL thickness in IVR-treated eyes (105.3±6.9µm and 74.4±11.2µm) were not different from those in untreated eyes in the IVR group (104.6± 8.4µm and 75.1±12.6µm) (P=0.57 and P=0.41, respectively). Similarly, overall and temporal RNFL thickness in IVB-treated eyes (105.8±8.1µm and 74.5±11.8µm) were not different from those in untreated eyes in the IVB group (104.6±8µm and 74.8±12.9µm) (P=0.42 and P=0.80, respectively). The frequencies of IOP rise (P=0.60) and changes in RNFL thickness from baseline (P=0.16) were comparable between groups. CONCLUSION Repeated intravitreal injection of ranibizumab or bevacizumab does not seem have adverse effects on RNFL thickness or IOP in wet AMD patients.

Choroidal Thickness Changes in the Acute Attack Period in Patients with Familial Mediterranean Fever.

Purpose: The aim of this study was to evaluate choroidal thickness changes during acute attacks of familial Mediterranean fever (FMF). Methods: Fifty patients with FMF and 50 healthy controls were included. Choroidal thickness of each participant was measured at the foveola and horizontal nasal and temporal quadrants at 500-µm intervals to 1,500 µm from the foveola using spectral-domain optical coherence tomography. White blood cell count, erythrocyte sedimentation rate (ESR) and serum levels of fibrinogen and C-reactive protein (CRP) were evaluated. The clinical findings (peritonitis, arthritis and pleuritis) were noted. Results: Choroidal thickness was significantly thicker at all measurement points in FMF patients compared to healthy controls during an acute attack (p < 0.05). There were positive correlations between the choroidal thickness and ESR, fibrinogen and, particularly, CRP levels. Clinical findings did not change the choroidal thickness significantly (p > 0.05). Conclusions: Increased choroidal thickness in the acute phase of FMF is possibly related to the inflammatory edematous changes in the choroid.

Diabetic Macular Edema.

Diabetic macular edema (DME), one the most prevalent causes of visual loss in industrialized countries, may be diagnosed at any stage of diabetic retinopathy. The diagnosis, treatment, and follow up of DME have become straightforward with recent developments in fundus imaging, such as optical coherence tomography. Laser photocoagulation, intravitreal injections, and pars plana vitrectomy surgery are the current treatment modalities; however, the positive effects of currently available intravitreally injected agents are temporary. At this point, further treatment choices are needed for a permanent effect. Sources of data selection: The articles published between 1985-2015 years on major databases were searched and most appropriate 40 papers were used to write this review article.

Retina nerve fiber layer and choroidal thickness changes in obstructive sleep apnea syndrome

ABSTRACT Objectives: The purpose of this study was to determine the effects of obstructive sleep apnea syndrome (OSAS) on the submacular and peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness (ChT). Methods: Eighty-four eyes of 42 male patients with OSAS and 112 eyes of 56 aged-matched and body mass index-matched healthy male subjects were enrolled in this case-control study. The ChT and peripapillary RNFL thickness was measured using enhanced depth imaging optical coherence tomography. The ChT and RNFL thickness measurements of the groups were compared, and correlations among the Apnea Hypopnea Index (AHI) values and these measurements were calculated. Right and left eyes were separately evaluated. Results: There were no significant differences in the subfoveal and temporal ChT between the groups (p > 0.05). The OSAS group had significantly thicker ChT at 0.5 and 1.5 mm nasal to the fovea in both eyes than the control group (p < 0.05). The peripapillary ChT were significantly thicker in the OSAS group at all segments except for the temporal and superotemporal segments when compared with the control group (p < 0.05 for all quadrants except temporal and superotemporal). When compared with controls, the OSAS group had significantly thinner nasal RNFL thickness in the right eye (p = 0.01) and thinner mean RNFL thickness in both eyes (p < 0.001). Other RNFL thickness measurements were similar between groups (p > 0.05). Between AHI and mean RNFL thickness showed a median negative correlation (r = − 0.411, p = 0.001). Conclusion: The choroidal thickening in patients with OSAS may be associated with the pathophysiology of the neurodegeneration process of the disease.

Comparison of Grid Laser, Intravitreal Triamcinolone, and Intravitreal Bevacizumab in the Treatment of Diffuse Diabetic Macular Edema

Purpose: To compare the effects of grid laser (GL), intravitreal bevacizumab (IVB), and intravitreal triamcinolone acetonide (IVTA) in diffuse diabetic macular edema (DDME). Procedures: One hundred and twenty-six patients (126 eyes) treated with GL (modified grid), IVTA (4 mg), and IVB (1.25 mg) injections, matched for best corrected visual acuity (BCVA) and OCT-based central macular thickness at presentation, were enrolled. Primary outcome measure was change in best corrected logMAR visual acuity at 1-year follow-up. Results: Rates of visual stabilization (within ±0.2 logMAR of baseline BCVA) (71.4, 83.3, 78.6%, respectively) were not different between the groups (p = 0.41) at 12-month follow-up. Higher rates of anatomical and functional success, however, were evident in IVB and IVTA groups within 6 months of treatment (p < 0.05 for both). No severe adverse effects except higher intraocular pressure (10 mm Hg from baseline) in one third (14 eyes) of the IVTA cases, who required trabeculectomy in 2 (4.8%) eyes, were observed. Conclusions: Intraocular injections may give favorable results within the first 6 months, and after 6 months, GL results seem to be more favorable in the treatment of treatment-naïve, acute, nonischemic, and center-involving DDME.

Prediction of Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma by Using Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio.

ABSTRACT Purpose: To assess the levels of neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) in patients with pseudoexfoliation syndrome (PEX) and to compare the NLR and PLR results of patients with PEX, PEX glaucoma (PXG), and healthy controls. Methods: In total, 34 patients with PEX, 29 patients with PXG, and 42 healthy subjects were enrolled in this retrospective study. Complete ophthalmologic examination and complete blood count measurements were performed of all subjects. Complete blood counts were performed within 2 h of blood collection. Results: There was a significant difference in NLR between PEX and control groups (p = 0.012) and PXG and control groups (p = 0.003). Also, a significant difference was found in PLR values between control and PXG groups (p = 0.024). Conclusions: Our study for the first time provides evidence that PLR and NLR may be useful for predicting the prognosis of PEX patients and progression to PXG.

Pars plana vitrectomy versus three intravitreal injections of bevacizumab for nontractional diabetic macular edema: A prospective, randomized comparative study.

Background: The aim of this study was to compare the effectiveness of pars plana vitrectomy (PPV) and removal of the internal limiting membrane (ILM) with three, monthly, intravitreal bevacizumab (IVB) injections for refractory diabetic macular edema. Materials and Methods: This was a prospective, randomized, comparative, interventional study. Forty-four patients were enrolled and randomized in two groups. Twenty-two eyes enrolled in Group I received three IVB injections at monthly interval. Twenty-two eyes were enrolled in Group II which underwent PPV with ILM removal. The primary outcomes measured were: (1) Best corrected logMAR visual acuity (BCVA) using Snellens visual acuity chart. (2) Central macular thickness (CMT) on optical coherence tomography. The secondary outcome measures were: Complication rates like (1) progression of lens opacities, (2) high intraocular pressure needing further treatment/procedure, (3) development of vitreous hemorrhage related to the procedure employed, (4) retinal detachment and (5) severe inflammation/endophthalmitis. Results: In Group I (IVB): 3 (13.6%) eyes showed no change in BCVA; 3 (13.6%) eyes reported decrease in BCVA and 16 (72.8%) eyes showed improvement in BCVA; (P = 0.0181). In Group II (PPV): 4 (18.2%) eyes showed no change in BCVA; 5 (22.7%) eyes showed decrease and 13 (59.1%) eyes showed improvement in BCVA (P = 0.0281). Mean decrease in CMT in IVB group was 108.45 μ, whereas mean decrease in CMT in PPV group was 161.36 μ. No major complications were seen in either group. Conclusion: Posttreatment decrease in CMT was more in PPV group and vision improvement more in IVB group. However, no statistically significant difference between the two methods was found.Background: The aim of this study was to compare the effectiveness of pars plana vitrectomy (PPV) and removal of the internal limiting membrane (ILM) with three, monthly, intravitreal bevacizumab (IVB) injections for refractory diabetic macular edema. Materials and Methods: This was a prospective, randomized, comparative, interventional study. Forty-four patients were enrolled and randomized in two groups. Twenty-two eyes enrolled in Group I received three IVB injections at monthly interval. Twenty-two eyes were enrolled in Group II which underwent PPV with ILM removal. The primary outcomes measured were: (1) Best corrected logMAR visual acuity (BCVA) using Snellens visual acuity chart. (2) Central macular thickness (CMT) on optical coherence tomography. The secondary outcome measures were: Complication rates like (1) progression of lens opacities, (2) high intraocular pressure needing further treatment/procedure, (3) development of vitreous hemorrhage related to the procedure employed, (4) retinal detachment and (5) severe inflammation/endophthalmitis. Results: In Group I (IVB): 3 (13.6%) eyes showed no change in BCVA; 3 (13.6%) eyes reported decrease in BCVA and 16 (72.8%) eyes showed improvement in BCVA; (P = 0.0181). In Group II (PPV): 4 (18.2%) eyes showed no change in BCVA; 5 (22.7%) eyes showed decrease and 13 (59.1%) eyes showed improvement in BCVA (P = 0.0281). Mean decrease in CMT in IVB group was 108.45 μ, whereas mean decrease in CMT in PPV group was 161.36 μ. No major complications were seen in either group. Conclusion: Posttreatment decrease in CMT was more in PPV group and vision improvement more in IVB group. However, no statistically significant difference between the two methods was found.

An animal model (guinea pig) of ocular siderosis: histopathology, pharmacology, and electrophysiology.

Abstract Purpose: Ocular siderosis is a rare sight-threatening complication that occurs after a penetrating ocular injury by an iron-containing foreign body. The purposes of this study were to (i) investigate the histopathology, electrophysiology and iron levels/accumulation in ocular siderosis using an animal (Guinea pig) model and (ii) determine the appropriate timing for follow-up foreign body-removal surgery. Materials and methods: Thirty guinea pigs were divided into five groups (n = 6 animals/group). On day-1, an iron body was inserted into the vitreous of the right eye of all animals; the left eyes were left undisturbed and were used as controls. At the end of each week during the 5-week study period, electroretinography (ERG) was performed on all animals in one of the five groups. Each animal in that group was sacrificed, after which both eyes were enucleated for histopathological and pharmacological evaluation of intraocular iron. Results: Accumulated iron levels of study eyes were significantly higher than those of control eyes (135.13 and 13.55 μg/g, respectively, p < 0.01). In addition, there was a significant decrease in electrophysiological responses of study eyes. During the first week, iron levels were higher in study eyes than control eyes, but neither histological iron accumulation nor decreased electrophysiological responses could be detected. By the end of the second week, increased iron accumulation was observed histologically in intraocular tissues, along with signs of retinal toxicity, as verified by decreased electrophysiological responses. Conclusions: The present study indicates that the 14th day after a penetrating eye injury by an iron-containing intraocular foreign body represents a clinically critical threshold, after which structural damage to and functional alterations in ocular tissues occur.