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.

Comparison of preoperative and postoperative measurements of optical low-coherence reflectometry biometry and assessment of its refractive predictability.

PURPOSE: To compare the preoperative and postoperative measurements of optical low-coherence reflectometry (OLCR) biometry and assessment of its refractive predictability. METHODS: A total of 114 eyes of 102 patients who underwent cataract treatment were prospectively examined. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), K (keratometry) 1, K2, K average (KAVE) and K astigmatic (KAST) values were recorded using Lenstar LS 900 (Haag-Streit, Koeniz, Switzerland) OLCR device. The IOL (intraocular lens) power was measured based on the SRK/T formula. The cases were divided into three subgroups according to AL (Group 1: AL < 22 mm, Group 2: 22 mm ≤ AL < 24 mm, Group 3: 24 mm ≤ AL). The mean absolute error (MAE) calculated for each eye. RESULTS: The right eyes of 45 patients (44.1%), left eyes of 45 patients (44.1%), and both eyes of 12 patients (11.7%) were examined. The average AL in the preoperative period was 23.19 ± 1.01; it was 23.20 ± 0.99 in the postoperative period (p > 0.05). A significant deepening was detected in the postoperative ACD (preop 2.76 ± 0.38 mm, postop 3.81 ± 0.46 mm, p < 0.001). CCT was measured as 521.4 ± 36.3 µm in the preoperative period and as 530.8 ± 42.8 (p > 0.05) µm in the postoperative period. The average mean absolute error (MAE) was measured as 0.48 ± 0.41 D, whereas refractive error was - 0.081 ± 0.67 D. The MAE distribution of cases was found to be ≤ 1.5 D 109 (95.6%) eyes, and ≤ 2.0 D in 114 (100%) eyes. MAE values according to AL of the cases were calculated as 0.71 ± 0.83 D in group 1, 0.49 ± 0.43 D in group 2 and 0.41 ± 0.36 D in group 3 (p > 0.05). CONCLUSION: When the measurement and refractive results of the OLCR biometry were evaluated, it was observed that there was a very satisfactory result and a predictable device compatible with the current literature. The SRK/T formula, one of the new generation formulas, has shown high MAE and RE results in eyes with AL ≤ 22 mm, although not statistically significant. Other new generation formulas should be tried in these eyes.

Epidemiology of uveitis in a referral hospital in Turkey.

AIM: To investigate the causes and clinical characteristics of uveitis in patients presenting to a specialized eye hospital in Turkey. MATERIALS AND METHODS: The clinical records of 1028 uveitis patients admitted between 1990 and 2010 were retrospectively reviewed. Age at first presentation, sex, laterality, etiology, associated systemic disease, clinical presentation, and course of the disease were noted. RESULTS: The mean age at presentation was 36.23 ± 14.9 years. Males constituted 58.2% of patients. Anatomically, anterior uveitis (42%) was most common, followed by posterior uveitis (24.9%), panuveitis (24.7%), and intermediate uveitis (8.4%). The course of the disease was mostly chronic (65.7%). The cases were idiopathic at 25.7% and Behçet's disease (BD) was the most common cause of uveitis (32.2%), followed by ocular toxoplasmosis (7.2%) and herpetic uveitis (6.8%). CONCLUSION: Uveitis tends to affect patients between 20 and 40 years old. BD is the most common cause, leading to male predominance and a higher frequency of a chronic course.