The effect of polycythemia vera on choroidal thickness and retrobulbar blood flow.

BACKGROUND: To evaluate the choroidal thickness and retrobulbar hemodynamic parameters in polycythemia vera (PV) patients in comparison with healthy individuals, and to investigate the relationship of these values with blood hematocrit levels. METHODS: This prospective study included the 35 eyes of 35 PV patients and the 30 eyes of 30 healthy individuals. Choroidal thickness was measured at the subfoveal area and at 500 µm intervals nasal and temporal to the fovea up to a distance of 1500 µm. Color Doppler ultrasonography (CDU) was used to evaluate the retrobulbar vessels. Complete blood count values were recorded. RESULTS: Choroidal thickness was found to be significantly lower in the PV group than in the control group at the subfoveal, nasal 500, and temporal 500 and 1000 µm measurement points (p = 0.01, p = 0.011, p = 0.04, p = 0.045, respectively). The central retinal artery (CRA) peak systolic velocity (PSV) and end diastolic velocity (EDV) values and the ophthalmic artery (OA) PSV value were significantly lower in the PV group than in the control group (p < 0.001, p < 0.001, p = 0.019, respectively). No significant difference was present between the groups in terms of CRA and OA resistive index (RI) and pulsatile index (PI) values (p = 0.388, p = 0.564, p = 0.897, p = 0.693, respectively). A negative correlation was found between the blood hematocrit levels and the subfoveal, nasal 500 µm, and temporal 500 µm choroidal thickness measurements and the CRA PSV and EDV and the OA PSV values. CONCLUSIONS: PV may cause microvascular changes and lead to ocular vascular complications by affecting the choroidal and retrobulbar blood flow.

The impact of obesity on ocular hemodynamics and choroidal thickness.

Background: Obesity affects microvascular structures. The effect of obesity on the ocular vascular system can be evaluated by changes in the choroidal thickness (CT) and retrobulbar blood flow (RBF). Objectives: To evaluate the CT and RBF parameters in obese patients with various body mass index (BMI) values and compare these parameters with normal weight, healthy subjects. Design: A prospective study. Methods: The study included 102 eyes of 102 female patients. Patients were divided into three groups according to BMI as group 1 with a BMI of 18.5-24.99 (n = 32), normal weight group; group 2 with a BMI of 30-34.99 (n = 35), as obese class I; and group 3 with a BMI of 35-39.99 (n = 35), as obese class II. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index, and pulsatility index values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography. CT was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm by using the enhanced depth imaging technique of optical coherence tomography. Intraocular pressure (IOP) was measured with a Goldmann applanation tonometry. Results: There was a significant difference in IOP values within the groups with the highest values in group 3 (17.6 ± 2.1 mmHg) and the lowest in group 1 (12.4 ± 1.7 mmHg). The CT in groups 2 and 3 was found to be statistically significantly lower than that in group 1 at all measurement points (p < 0.001). There was a statistically significant negative correlation between CT at all measurement points and BMI (p < 0.001). The mean CRA PSV, EDV, and OA EDV values were statistically significantly lower in each obese group than those values in group 1 (p < 0.001). The OA PSV values were significantly lower in group 3 (36.5 ± 5.9 cm/s) than those in group 2 (43.8 ± 4 cm/s) and group 1 (44.6 ± 5.2 cm/s) (p < 0.001). Also, significant associations were found between BMI and CRA PSV, CRA EDV, and OA PSV values (p < 0.001). Conclusion: Obesity may predispose to eye pathologies by changing the ocular vascular circulation.

Retrobulbar ocular blood flow and choroidal vascular changes in patients recovering from COVID-19 infection.

BACKGROUND: To evaluate the effects of COVID-19 infection on the ocular vascular structure including choroidal thickness and retrobulbar blood flow values in comparison with healthy subjects. METHODS: Ninety eyes of 90 patients were included in this study. Participants were divided into Group 1 (n = 30) with mild COVID-19 infection, Group 2 (n = 31) with moderate disease, and Group 3 with age- and sex-matched healthy subjects (n = 29). Choroidal thickness was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm, using the enhanced depth imaging (EDI) technique of spectral coherence tomography (SD-OCT). The peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography (CDU). RESULTS: The choroidal thickness was significantly thinner in Group 1 and Group 2 than in Group 3 at all measurement points (p <0.001). This difference was not present between Group 1 and Group 2 who had COVID-19 disease of different severity (p>0.05).Among the retrobulbar blood flow parameters, OA PSV value was significantly lower in Group 1 and Group 2 compared to Group 3 (p = 0.025, p = 0.016, respectively). However, the CRA PSV and EDV and OA EDV values, and the CRA and OA PI and RI values were not statistically different between the groups (p> 0.05). CONCLUSION: COVID-19 infection may predispose patients to ocular vascular pathologies by affecting both choroidal and retrobulbar blood flow.

Screening for retinopathy of prematurity in a tertiary hospital in Istanbul: incidence and risk factors.

PURPOSE: To study the incidence and risk factors of retinopathy of prematurity (ROP) in premature infants examined in a tertiary hospital in Istanbul. METHODS: Data of infants screened for ROP from April 2007 to September 2009 were retrospectively reviewed. Possible risk factors and eye examinations were recorded and analyzed using the chi-square test and univariate and multivariate regressions. RESULTS: ROP was detected in 177 (34.3%) of the 517 infants enrolled in the study; 64 had mild ROP (77.4%) and 38 had severe ROP (22.6%). The mean gestational age and birth weight of patients who were treated for ROP were 28.6 ± 2.3 and 1,143.5 ± 337.4, respectively. Two of these infants had a gestational age of 32 g or greater and three had a birth weight of 1,500 g or greater. The multivariate regression analyses showed gestational age, birth weight, sepsis, respiratory distress syndrome, and length of oxygen therapy as independent predictors of ROP. CONCLUSION: The incidence of ROP observed in this study was higher than that in developed countries and relatively more mature infants were affected. Criteria including gestational age of less than 34 weeks or birth weight of less than 2,000 g would have identified all infants who were at risk.

Twenty-four-hour intraocular pressure control with latanoprost-timolol-fixed combination versus bimatoprost in patients who switched from timolol.

PURPOSE: To evaluate bimatoprost versus latanoprost and timolol fixed combination (LTFC) over the 24-hour diurnal curve in patients who switched from timolol. METHODS: In this prospective, observer-masked, randomized clinical trial, 64 patients whose intraocular pressures (IOPs) were not effectively controlled with timolol were enrolled. At pretrial visit IOPs and central corneal thickness were measured. After the baseline visit, timolol was replaced by bimatoprost or LTFC. IOPs were recorded at 8 AM, noon, 4 PM, 8 PM, midnight, and 4 AM at baseline, week 8, and week 16 visits. RESULTS: At baseline and week 8 visits, there was no significant difference between the LTFC and bimatoprost group for the mean IOPs at 6 time points in 24 hours, the mean diurnal IOP, and range of diurnal IOP. At week 16, the mean IOP of the bimatoprost group (15.7±2 mm Hg) at 8 AM and 12 o' clock, midnight, was statistically significantly lower than that of the LTFC group (16.8±1.5 and 16.9±1.7 mm Hg; P=0.03 and 0.002). A statistically significant difference was not found between the proportions of patients who had 15% and 20% decrease in mean diurnal IOP and the mean daytime, nighttime, diurnal IOP reductions of the 2 study groups at weeks 8 and 16 (P>0.05). In the bimatoprost group punctate epitheliopathy, conjunctival hyperemia, and lid erythema were found to be more frequent. CONCLUSIONS: The LTFC and bimatoprost therapies were equally effective in maintaining IOP at lower levels during the 24-hour period in patients who switched from timolol therapy. Adverse events were more frequent with bimatoprost therapy.

Differences in contrast sensitivity between monofocal, multifocal and accommodating intraocular lenses: long-term results.

BACKGROUND: To evaluate long-term contrast sensitivity (CS) and visual acuity following implantation of monofocal, accommodating, refractive and diffractive multifocal intraocular lenses (IOLs) in patients with unilateral cataract. METHODS: In this prospective non-randomized clinical trial, 87 patients with unilateral cataract were enrolled in four groups for phacoemulsification and IOL implantation in Ophthalmology Department of Goztepe Training and Research Hospital. Twenty-four patients had monofocal (Alcon Acrysof; group 1), 21 patients accommodating (Human Optics 1CU; group 2), 22 patients diffractive multifocal (Tecnis ZM900; group 3) and 20 patients refractive multifocal (AMO Rezoom; group 4) IOL implantations. Ages of patients were between 40 and 70. Parameters analysed at the 18th postoperative month were subjective refractions, monocular and binocular distance and near photopic CSs, visual acuities. RESULTS: Near visual acuities were statistically better in group 3 than the other groups (P < 0.05). At low spatial frequencies, mean monocular distance CSs of group 1 and mean monocular near CSs of groups 1 and 2 were statistically higher than those of group 4 (P < 0.05). There was no significant difference between binocular CSs of group 4 and the other groups at low spatial frequencies. At high spatial frequencies, monocular and binocular CSs of groups 1 and 2 were statistically higher than those of groups 3 and 4 (P < 0.05). Near CSs was better in group 3 than group 4. CONCLUSIONS: In patients with unilateral cataract, monofocal, accommodating and partially diffractive multifocal IOL provided higher CS scores when compared with refractive multifocal IOL and in multifocal IOL groups binocular CSs were better than monocular CSs when compared with other groups.

Effects of pretreatment with different topical vasodilators on blood flow in the internal mammary artery: a prospective randomized study.

BACKGROUND: This study was conducted to investigate how brief pretreatments with 4 different vasodilators applied topically at normal body temperature affect blood flow in the internal mammary artery. METHODS: One hundred patients who had an internal mammary artery mobilized as a pedicle for coronary artery bypass grafting were randomly assigned to one of 5 groups of equal size (20 subjects in each). Each group of pedicles was treated with a different topical solution: normal saline (control), nitroglycerin, diltiazem, papaverine, or adenosine. Internal mammary artery flow and hemodynamic measurements were recorded immediately after harvesting and after 5 minutes of immersion in a tube filled with test solution (50 mL at 37 degrees C). Results for each study variable were compared within and between groups, and posttreatment-to-pretreatment ratios were also calculated and compared. RESULTS: All 4 vasodilator groups showed a significant increase in internal mammary artery flow rate from pretreatment to posttreatment, whereas the saline group did not. There were no significant differences among the 5 groups' pretreatment flow rates (P = .526) or posttreatment flow rates (P = .194). The mean ratio values (posttreatment-to-pretreatment) for flow rate were 1.08 +/- 0.17 in the saline group, 1.74 +/- 0.17 with nitroglycerin, 1.77 +/- 0.49 with diltiazem, 1.82 +/- 0.59 with papaverine, and 1.57 +/- 0.54 with adenosine. Post hoc analysis revealed that the mean ratio values for flow rate in the 4 vasodilator groups were significantly higher than the corresponding ratio in the saline group. CONCLUSIONS: Brief treatment of the internal mammary artery with topical vasodilators at normal body temperature significantly increases blood flow in this vessel. The data from this study are particularly valuable in relation to off-pump surgery, in which this vessel is usually anastomosed soon after it is harvested.