Prediction of anemia in real-time using a smartphone camera processing conjunctival images.

Anemia is defined as a low hemoglobin (Hb) concentration and is highly prevalent worldwide. We report on the performance of a smartphone application (app) that records images in RAW format of the palpebral conjunctivae and estimates Hb concentration by relying upon computation of the tissue surface high hue ratio. Images of bilateral conjunctivae were obtained prospectively from a convenience sample of 435 Emergency Department patients using a dedicated smartphone. A previous computer-based and validated derivation data set associating estimated conjunctival Hb (HBc) and the actual laboratory-determined Hb (HBl) was used in deriving Hb estimations using a self-contained mobile app. Accuracy of HBc was 75.4% (95% CI 71.3, 79.4%) for all categories of anemia, and Bland-Altman plot analysis showed a bias of 0.10 and limits of agreement (LOA) of (-4.73, 4.93 g/dL). Analysis of HBc estimation accuracy around different anemia thresholds showed that AUC was maximized at transfusion thresholds of 7 and 9 g/dL which showed AUC values of 0.92 and 0.90 respectively. We found that the app is sufficiently accurate for detecting severe anemia and shows promise as a population-sourced screening platform or as a non-invasive point-of-care anemia classifier.

Association between dryness sensation and ocular surface temperature and conjunctival blood flow in soft contact lens wearers.

PURPOSE: To investigate the association between dryness, ocular surface temperature (OST), and conjunctival blood flow (CBF) in soft contact lens (SCL) wearers after airflow stimulation. METHODS: After recruiting 21 SCL wearers (mean age, 25.3 ± 4.2 years), subjects used two different daily disposable silicone hydrogel SCLs (narafilcon A and delefilcon A lenses). On three of four measurement days, excluding the first, OST, CBF, tear meniscus height (TMH), and non-invasive tear break-up time (NIBUT) were measured after airflow stimulation at a rate of 3 m/s for 10 min. The measurements were conducted without SCLs on the first and second days, and with different SCLs on the third and fourth days. Dryness was evaluated using the visual analogue scale (VAS). These parameters were compared between the two types of SCLs, and their association with the dryness sensation was then investigated. RESULTS: Dryness was significantly weakly correlated with OST (r = -0.375, p < 0.05) and CBF (r = 0.339, p < 0.05). TMH, NIBUT, and VAS scores for dryness with the delefilcon A lens (0.15 ± 0.05 mm, 3.7 ± 01.7 s and 29.4 ± 16.9) were significantly higher, longer, and lower, respectively, than those with the narafilcon A lens (0.12 ± 0.05 mm, 2.3 ± 1.7 s and 35.9 ± 17.0; p < 0.05, p < 0.01 and p < 0.01). The changes in the OST and CBF between with and without the delefilcon A lens (-0.36 ± 0.35 °C and 0.99 ± 0.19) were significantly small compared to the narafilcon A lens (-0.60 ± 0.42 °C and 1.11 ± 0.21; p < 0.01 for both comparisons). CONCLUSION: Dryness was correlated with OST and CBF, which indicates that when dryness was high, OST was low and CBF was high. These results suggest that OST and CBF assessments are effective for evaluating dryness sensation.

MINE-BLAST TRAUMA AS A FACTOR IN THE EARLY DEVELOPMENT OF VASCULAR DISEASES OF THE BRAIN.

OBJECTIVE: The aim of this study is to investigate the state of bulbar conjunctival vessels, rheological properties of blood, catecholamines (adrenaline, norepinephrine), lipid metabolism, alkaline proteins of blood serum in patients with consequences of mild combat traumatic brain injury. PATIENTS AND METHODS: Materials and methods: 76 individuals aged 28 to 41 years were examined. The duration of the injury lasted from 2 to 4 years. The control group consisted of 28 individuals aged 45 to 49 years with primary cerebral atherosclerosis and manifestations of cerebral circulation disorders. The state of the bulbar conjunctiva vessels and blood circulation was studied using a slit lamp SHCHL-2B at 40-fold magnification. Rheological parameters, lipid metabolism, serum alkaline proteins, total catecholamines were studied according to generally accepted methods. RESULTS: Results: Changes in the vessels of the bulbar conjunctiva (stage II-III) were detected in 76% of the subjects, indicating the formation of cerebral vascular pathology, and in 87% of patients with initial cerebral atherosclerosis. The analysis of lipid metabolism showed significantly (p<0.05) increased data on all studied parameters (cholesterol, high-density lipoprotein, ß-lipoprotein, atherogenic index), both in patients with aftereffects of mild combat traumatic brain injury and in patients with initial cerebral atherosclerosis. An increase in alkaline proteins indices we detected in 62% of patients with aftereffects of mild combat cerebral trauma and in 55% of patients with initial cerebral atherosclerosis. At the same time, there was an increase in total catecholamines in the erythrocytes of patients with combat head injury. An increase in fibrinogen was noted in both groups, but in the group with initial cerebral atherosclerosis it was more pronounced. CONCLUSION: Conclusions: Combat traumatic brain injury contributes to the early formation of cerebral atherosclerosis and cerebral circulation disorders in this category of patients. The examination methods we have studied should be included in the survey plan for these patients. They are important not only for diagnosis, but also for improving treatment and preventing vascular disasters.

Novel Application of Conjunctival Anterior Segment Optical Coherence Tomography Angiography to Assess Ocular Redness.

PURPOSE: The aim of this study was to determine anterior segment optical coherence tomography angiography (AS-OCTA) parameters to assess ocular redness severity. METHODS: AS-OCTA analyses of 60 eyes of 40 patients were grouped according to ocular redness stages using the 5-category validated bulbar redness scale in a cross-sectional retrospective study (groups 1-5). A subset of patients with slit-lamp photographs, total 35 eyes of 23 patients, were assessed with 10-category validated bulbar redness scale for comparison. AS-OCTA images of nasal and temporal bulbar conjunctiva were analyzed. Vessel density (VD) represented the blood flow pixels by the total pixels of image (%); vessel diameter index represented the VD by the skeletonized density; fractal dimension, measured with the box-count method, represented the vessel branching complexity. Averaged nasal and temporal parameters for each eye were correlated to validated bulbar redness scales. RESULTS: There was no statistical difference between groups for age ( P = 0.118), sex ( P = 0.501), eye laterality (OD/OS; P = 0.111), or location (nasal/temporal; P = 0.932). In the 5-category scale, VD significantly increased from group 1 to 2 (31.5 ± 1.9% and 33.4 ± 2.2%, P = 0.023), 2 to 3 (36.0 ± 3.5%, P < 0.001), and 4 to 5 (40.2 ± 2.9 and 46.5 ± 2.8, P < 0.001). The correlations were 0.805 ( P < 0.001) and 0.893 ( P < 0.001) for the 5-category and 10-category scales, respectively. Vessel diameter index showed a significant increase from 1 to 2 (2.90 ± 0.17 and 3.00 ± 0.15; P = 0.004) and 4 to 5 (2.92 ± 0.31 and 3.33 ± 0.08; P = 0.001). The correlations were 0.550 ( P < 0.001) and 0.625 ( P < 0.001) for the respective scales. The fractal dimension showed no significant differences between subsequent groups. The correlations were 0.445 ( P < 0.001) and 0.583 ( P < 0.001), respectively. CONCLUSIONS: Conjunctival AS-OCTA VD was the most reliable parameter to assess ocular redness.

Conjunctival microcirculation in ocular and systemic microvascular disease.

The conjunctival microcirculation is an accessible complex network of micro vessels whose quantitative assessment can reveal microvascular haemodynamic properties. Currently, algorithms for the measurement of conjunctival haemodynamics use either manual or semi-automated systems, which may provide insight into overall conjunctival health, as well as in ocular and systemic disease. These algorithms include functional slit-lamp biomicroscopy, laser doppler flowmetry, optical coherence tomography angiography, orthogonal polarized spectral imaging, computer-assisted intravitral microscopy, diffuse reflectance spectroscopy and corneal confocal microscopy. Furthermore, several studies have demonstrated a relationship between conjunctival microcirculatory haemodynamics and many diseases such as dry eye disease, Alzheimer's disease, diabetes, hypertension, sepsis, coronary microvascular disease, and sickle cell anaemia. This review aims to describe conjunctival microcirculation, its characteristics, and techniques for its measurement, as well as the association between conjunctival microcirculation and microvascular abnormalities in disease states.

Assessment of Indices of Conjunctival Microvascular Function in Patients With and Without Obstructive Coronary Artery Disease.

BACKGROUND: Atherosclerotic heart disease often remains asymptomatic until presentation with a major adverse cardiovascular event. Primary preventive therapies improve outcomes, but conventional screening often misattributes risk. Vascular imaging can be utilised to detect atherosclerosis, but often involves ionising radiation. The conjunctiva is a readily accessible vascular network allowing non-invasive hemodynamic evaluation. AIM: To compare conjunctival microcirculatory function in patients with and without obstructive coronary artery disease. METHODS: We compared the conjunctival microcirculation of myocardial infarction patients (MI-cohort) to controls with no obstructive coronary artery disease (NO-CAD cohort). Conjunctival imaging was performed using a smartphone and slit-lamp biomicroscope combination. Microvascular indices of axial (Va) and cross-sectional (Vcs) velocity; blood flow rate (Q); and wall shear rate (WSR) were compared in all conjunctival vessels between 5 and 45 µm in diameter. RESULTS: A total of 127 patients were recruited (66 MI vs 61 NO-CAD) and 3602 conjunctival vessels analysed (2414 MI vs 1188 NO-CAD). Mean Va, Vcs and Q were significantly lower in the MI vs NO-CAD cohort (Va 0.50 ± 0.17 mm/s vs 0.55 ± 0.15 mm/s, p < 0.001; Vcs 0.35 ± 0.12 mm/s vs 0.38 ± 0.10 mm/s, p < 0.001; Q 154 ± 116 pl/s vs 198 ± 130 pl/s, p < 0.001). To correct for differences in mean vessel diameter, WSR was compared in 10-36 µm vessels (3268/3602 vessels) and was lower in the MI-cohort (134 ± 64 s-1 vs 140 ± 63 s-1, p = 0.002). CONCLUSIONS: Conjunctival microcirculatory alterations can be observed in patients with obstructive coronary artery disease. The conjunctival microvasculature merits further evaluation in cardiovascular risk screening.

Progress of Bulbar Conjunctival Microcirculation Alterations in the Diagnosis of Ocular Diseases.

Bulbar conjunctival microcirculation is a microvascular system distributed in the translucent bulbar conjunctiva near the corneal limbus. Multiple ocular diseases lead to bulbar conjunctival microcirculation alterations, which means that bulbar conjunctival microcirculation alterations would be potential screening and diagnostic indicators for these ocular diseases. In recent years, with the emergence and application of a variety of noninvasive observation devices for bulbar conjunctiva microcirculation and new image processing technologies, studies that explored the potential of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases have been emerging. However, the potential of bulbar conjunctival microcirculation alterations as indicators for ocular diseases has not been exploited to full advantage. The observation devices, image processing methods, and algorithms are not unified. And large-scale research is needed to concrete bulbar conjunctival microcirculation alterations as indicators for ocular diseases. In this paper, we provide an update on the progress of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases in recent five years (from January 2017 to March 2022). Relevant ocular diseases include contact lens wearing, dry eye, conjunctival malignant melanoma, conjunctival nevus, and diabetic retinopathy.

Human ocular surface microcirculation quantified by in vivo computer assisted video microscopy and diffuse reflectance spectroscopy.

Non-invasive imaging techniques are increasingly used to objectively quantify anterior segment structures of the eye. In this study, we apply the novel oxygen delivery index (ODIN) concept that, quantifies microvascular capacity for oxygen delivery, to the ocular surface in healthy humans. The purpose of the study was to test the applicability of the technologies used for data acquisition from the human ocular surface. We also validated whether the ODIN concept has sufficient sensitivity to detect and differentiate between microvascular structure and function in limbal and bulbar conjunctiva. Multiple ocular surface measurements using computer-assisted video microscopy (field of view: 1.6 mm × 0.9 mm) and diffuse reflectance spectroscopy (measuring volume: ∼0.1 mm3) were obtained from limbal and bulbar conjunctiva in 20 healthy volunteers. Three parameters were extracted during analyses: Functional capillary density, capillary flow velocity, and microvascular oxygen saturation. Functional capillary density was higher at limbus than in bulbar conjunctiva (11.2 ± 1.8 c/mm versus 5.2 ± 1.2 c/mm, p < 0.01), and microvascular oxygen saturation was lower at limbus (77 ± 8%) as compared to bulbar conjunctiva (89 ± 6%), p < 0.01. More than 80% of scored capillaries had continuous blood flow and no difference was seen between the recording sites (p = 0.68). In conclusion, the ODIN concept is applicable for the assessment of human ocular surface microvascular function and has sufficient sensitivity to detect increased capillary density and oxygen extraction at limbus as compared with bulbar conjunctiva.

Associations Between Lid Wiper Microvascular Responses, Lens Fit, and Comfort After One Day of Contact Lens Adaptation by Neophytes.

PURPOSE: To determine associations between lid wiper microvascular responses, lens fit, and comfort after 1 day of contact lens adaptation by neophytes. METHODS: Functional slitlamp biomicroscopy was used to image the microvascular network of the upper tarsal conjunctiva, lid wiper, and bulbar conjunctiva. Fractal dimension was obtained to represent vessel density. Ultra-high-resolution optical coherence tomography was used to image the lens edge and fitting characteristics, including lens movement and lens-induced conjunctival indentation. Ocular comfort was rated using a 50-point visual analogue scale (VAS). Forty-nine healthy subjects without a history of contact lens wear were recruited. A contact lens was then fitted in the right eye. Imaging was taken at baseline and 6 hr after lens wear. RESULTS: The changes of VAS comfort score were negatively related to the changes of the vessel density in the lid-wiper (R 2 =0.18, P =0.002) and bulbar conjunctiva (R 2 =0.13, P =0.009). However, the changes of VAS were positively related to the changes in vessel density of the tarsal conjunctiva (R 2 =0.11, P =0.02). The changes of ocular microvasculature were not related to the objective metrics of the lens-fitting characteristics ( P >0.05). Similarly, the changes in the VAS comfort score were not related to the objective metrics of the lens-fitting characteristics ( P >0.05). CONCLUSION: Contact lens discomfort seemed to relate to lid wiper microvascular responses rather than fitting characteristics after 1 day of contact lens adaptation by neophytes.

A novel algorithm for cardiovascular screening using conjunctival microcirculatory parameters and blood biomarkers.

Microvascular haemodynamic alterations are associated with coronary artery disease (CAD). The conjunctival microcirculation can easily be assessed non-invasively. However, the microcirculation of the conjunctiva has not been previously explored in clinical algorithms aimed at identifying patients with CAD. This case-control study involved 66 patients with post-myocardial infarction and 66 gender-matched healthy controls. Haemodynamic properties of the conjunctival microcirculation were assessed with a validated iPhone and slit lamp-based imaging tool. Haemodynamic properties were extracted with semi-automated software and compared between groups. Biomarkers implicated in the development of CAD were assessed in combination with conjunctival microcirculatory parameters. The conjunctival blood vessel parameters and biomarkers were used to derive an algorithm to aid in the screening of patients for CAD. Conjunctival blood velocity measured in combination with the blood biomarkers (N-terminal pro-brain natriuretic peptide and adiponectin) had an area under receiver operator characteristic curve (AUROC) of 0.967, sensitivity 93.0%, specificity 91.5% for CAD. This study demonstrated that the novel algorithm which included a combination of conjunctival blood vessel haemodynamic properties, and blood-based biomarkers could be used as a potential screening tool for CAD and should be validated for potential utility in asymptomatic individuals.

A meta-analysis of variability in conjunctival microvascular hemorheology metrics.

Conjunctival hemorheology has been used analytically to assess qualities of blood flow associated with various forms of cardiovascular disorders including diabetes mellitus, stroke, and sickle cell disease. Although conjunctival axial red blood cell velocity (Vax) has been demonstrated in varying disease states, benchmark measures of Vax are not well-defined. Due to various methodologic differences in assessment of Vax, interstudy consistency of hemorheological metrics is susceptible to both systematic and random error. Our study examines interstudy heterogeneity of Vax as measured in the conjunctival microvasculature of healthy subjects and assesses the overall perturbation of Vax based on disease state. Furthermore, our study aims to establish a potential range of normative Vax by comparing inter-study measurements in healthy patients. The most widely employed analytic approach to assess Vax was space-time analysis (n = 30). Using a meta-analytic approach, the prediction interval for Vax in healthy subjects among 20 studies ranged from 0.32-2.60 mm/s with a combined effect size of 0.52 ± 0.03 (CI: 0.46-0.59) mm/s. Inter-study comparison of Vax in healthy patients showed a high degree of variability (I2: 98.96%), due to studies with low measurement precision and/or dissimilar analytic methodology. Neither age nor diameter was a clinically significant moderator of Vax measurements in healthy patients. The combined effect size, defined as the composite Hedge's g of studies comparing healthy and disease state mean Vax, was 0.21 ± 0.13. High heterogeneity (I2: 80.48%) was observed in studies analyzing the difference between mean Vax in healthy and disease state patients. This heterogeneity was also observed when the difference in mean Vax between healthy and disease state patients was assessed in subgroups based on disease condition (I2: vascular disease 33%, sickle cell disease 62.22%, other 83.43%). Age was found to be a significant moderator (p = 0.048, ß = -0.40) of Hedge's g while diameter was not. No significant publication bias was observed in studies presenting healthy patient Vax or in studies comparing Vax between healthy and disease state patients. In summary, although homogeneity can be seen in healthy group Vax measurements, a high degree of statistical heterogeneity is found in Vax assessment comparing healthy and disease conditions that is not fully explained by methodologic variability.

Identifying diabetes from conjunctival images using a novel hierarchical multi-task network.

Diabetes can cause microvessel impairment. However, these conjunctival pathological changes are not easily recognized, limiting their potential as independent diagnostic indicators. Therefore, we designed a deep learning model to explore the relationship between conjunctival features and diabetes, and to advance automated identification of diabetes through conjunctival images. Images were collected from patients with type 2 diabetes and healthy volunteers. A hierarchical multi-tasking network model (HMT-Net) was developed using conjunctival images, and the model was systematically evaluated and compared with other algorithms. The sensitivity, specificity, and accuracy of the HMT-Net model to identify diabetes were 78.70%, 69.08%, and 75.15%, respectively. The performance of the HMT-Net model was significantly better than that of ophthalmologists. The model allowed sensitive and rapid discrimination by assessment of conjunctival images and can be potentially useful for identifying diabetes.

The Role of Conjunctival Microvasculation Combined with Echocardiography in Evaluating Pulmonary Arterial Hypertension in Systemic Lupus Erythematosus.

OBJECTIVE: To explore the role of conjunctival microvasculation combined with echocardiography in evaluating the prognosis of pulmonary arterial hypertension in systemic lupus erythematosus (SLE-PAH). METHODS: We prospectively compared the conjunctival microvascular changes in 17 SLE-PAH patients and 34 SLE patients without PAH in our hospital from January 2020 to December 2020, and we observed the characteristics of conjunctival microvascular changes in SLE-PAH patients. We analyzed the correlation between the corresponding conjunctival microvascular changes and cardiopulmonary function and evaluated the predictive value of the vessel density (VD) and the microvascular flow index (MFI) of conjunctival microvasculation combined with echocardiography in SLE-PAH. RESULTS: Compared with SLE patients without PAH, the ischemic areas in conjunctival microvasculation were significantly increased in SLE-PAH patients. The VD and MFI of conjunctival microvasculation are significantly correlated with N-terminal prohormone of brain natriuretic peptide and 6-minute walking distance. Combined with the VD and MFI, it can improve the accuracy of echocardiography in assessing the risk of death due to SLE-PAH (94.1% vs. 82.2%). CONCLUSION: The ischemic area, VD, and MFI of conjunctival microvasculation in SLE-PAH patients can indicate the occurrence of severe SLE-PAH and improve the accuracy of echocardiography in evaluating the prognosis of SLE-PAH.

Prediction of anemia and estimation of hemoglobin concentration using a smartphone camera.

Anemia, defined as a low hemoglobin concentration, has a large impact on the health of the world's population. We describe the use of a ubiquitous device, the smartphone, to predict hemoglobin concentration and screen for anemia. This was a prospective convenience sample study conducted in Emergency Department (ED) patients of an academic teaching hospital. In an algorithm derivation phase, images of both conjunctiva were obtained from 142 patients in Phase 1 using a smartphone. A region of interest targeting the palpebral conjunctiva was selected from each image. Image-based parameters were extracted and used in stepwise regression analyses to develop a prediction model of estimated hemoglobin (HBc). In Phase 2, a validation model was constructed using data from 202 new ED patients. The final model based on all 344 patients was tested for accuracy in anemia and transfusion thresholds. Hemoglobin concentration ranged from 4.7 to 19.6 g/dL (mean 12.5). In Phase 1, there was a significant association between HBc and laboratory-predicted hemoglobin (HBl) slope = 1.07 (CI = 0.98-1.15), p<0.001. Accuracy, sensitivity, and specificity of HBc for predicting anemia was 82.9 [79.3, 86.4], 90.7 [87.0, 94.4], and 73.3 [67.1, 79.5], respectively. In Phase 2, accuracy, sensitivity and specificity decreased to 72.6 [71.4, 73.8], 72.8 [71, 74.6], and 72.5 [70.8, 74.1]. Accuracy for low (<7 g/dL) and high (<9 g/dL) transfusion thresholds was 94.4 [93.7, 95] and 86 [85, 86.9] respectively. Error trended with increasing HBl values (slope 0.27 [0.19, 0.36] and intercept -3.14 [-4.21, -2.07] (p<0.001) such that HBc tended to underestimate hemoglobin in higher ranges and overestimate in lower ranges. Higher quality images had a smaller bias trend than lower quality images. When separated by skin tone results were unaffected. A smartphone can be used in screening for anemia and transfusion thresholds. Improvements in image quality and computational corrections can further enhance estimates of hemoglobin.

The role of cyclin D1, BCL-2, p53 and Ki-67 in epithelial cells in the etiopathogenesis of pterygium.

CONTEXT: Pterygium is a degenerative disease that consists of conjunctival epithelia and fibrovascular tissue. Some studies suggest that there is a defect in the regulation of apoptosis in the epithelial cell cycle characterized by the development of the disease. But, still this matter being debated. AIMS: In this study, the clinical, histopathological data, and the expression of the cell cycle regulator Cyclin D1, anti-apoptotic BCL-2, tumor suppressor p53, and cell proliferation marker Ki-67 were searched in pterygium samples. SUBJECTS AND METHODS: The study enrolled 62 cases of primary pterygium who underwent excision between 2014 and 2017. Recurrent and pseudo-pterygium cases were excluded from series. The clinical data were obtained from the patient files and the slides were reevaluated for the histopathological data. Slides of all were stained by Cyclin D1, BCL-2, and Ki-67 by the immunohistochemical method. For each immunohistochemical marker, first the staining was determined as negative or positive. Then if there is a staining, the hot zone (the area containing more positive cells) was determined and staining percentage (SP) was assessed by counting positive cells/100 epithelial cells). RESULTS: Solar elastosis, edema, inflammation, and epithelial dysplasia were found statistically different between the control group and the patient group (P value <0.001, <0.001, <0.001 <0.001, respectively). A significant difference was found for staining percentage (SP) of Ki-67, p53, BCL-2 between the control group and the patient group (P values <0.001, 0.002, <0.001, respectively). There were no significant differences in the SP of Cyclin D1 between the two groups (p: 0,133). CONCLUSIONS: Our results indicate an abnormal expression of p53, BCL-2 and elevated proliferation measured by Ki-67 in pterygium samples when compared to normal conjunctiva. Besides the mesenchymal changes, the increased proliferation and the failure of apoptosis in the epithelial cells participate in the development of pterygium, as well.

Assessment of the conjunctival microcirculation in adult patients with cyanotic congenital heart disease compared to healthy controls.

PURPOSE: Congenital heart disease (CHD) is the most common live birth defect and a proportion of these patients have chronic hypoxia. Chronic hypoxia leads to secondary erythrocytosis resulting in microvascular dysfunction and increased thrombosis risk. The conjunctival microcirculation is easily accessible for imaging and quantitative assessment. It has not previously been studied in adult CHD patients with cyanosis (CCHD). METHODS: We assessed the conjunctival microcirculation and compared CCHD patients and matched healthy controls to determine if there were differences in measured microcirculatory parameters. We acquired images using an iPhone 6s and slit-lamp biomicroscope. Parameters measured included diameter, axial velocity, wall shear rate and blood volume flow. The axial velocity was estimated by applying the 1D + T continuous wavelet transform (CWT). Results are for all vessels as they were not sub-classified into arterioles or venules. RESULTS: 11 CCHD patients and 14 healthy controls were recruited to the study. CCHD patients were markedly more hypoxic compared to the healthy controls (84% vs 98%, p = 0.001). A total of 736 vessels (292 vs 444) were suitable for analysis. Mean microvessel diameter (D) did not significantly differ between the CCHD patients and controls (20.4 ± 2.7 µm vs 20.2 ± 2.6 µm, p = 0.86). Axial velocity (Va) was lower in the CCHD patients (0.47 ± 0.06 mm/s vs 0.53 ± 0.05 mm/s, p = 0.03). Blood volume flow (Q) was lower for CCHD patients (121 ± 30pl/s vs 145 ± 50pl/s, p = 0.65) with the greatest differences observed in vessels >22 µm diameter (216 ± 121pl/s vs 258 ± 154pl/s, p = 0.001). Wall shear rate (WSR) was significantly lower for the CCHD group (153 ± 27 s-1 vs 174 ± 22 s-1, p = 0.04). CONCLUSIONS: This iPhone and slit-lamp combination assessment of conjunctival vessels found lower axial velocity, wall shear rate and in the largest vessel group, lower blood volume flow in chronically hypoxic patients with congenital heart disease. With further study this assessment method may have utility in the evaluation of patients with chronic hypoxia.

Assessment of the conjunctival microcirculation for patients presenting with acute myocardial infarction compared to healthy controls.

Microcirculatory dysfunction occurs early in cardiovascular disease (CVD) development. Acute myocardial infarction (MI) is a late consequence of CVD. The conjunctival microcirculation is readily-accessible for quantitative assessment and has not previously been studied in MI patients. We compared the conjunctival microcirculation of acute MI patients and age/sex-matched healthy controls to determine if there were differences in microcirculatory parameters. We acquired images using an iPhone 6s and slit-lamp biomicroscope. Parameters measured included diameter, axial velocity, wall shear rate and blood volume flow. Results are for all vessels as they were not sub-classified into arterioles or venules. The conjunctival microcirculation was assessed in 56 controls and 59 inpatients with a presenting diagnosis of MI. Mean vessel diameter for the controls was 21.41 ± 7.57 µm compared to 22.32 ± 7.66 µm for the MI patients (p < 0.001). Axial velocity for the controls was 0.53 ± 0.15 mm/s compared to 0.49 ± 0.17 mm/s for the MI patients (p < 0.001). Wall shear rate was higher for controls than MI patients (162 ± 93 s-1 vs 145 ± 88 s-1, p < 0.001). Blood volume flow did not differ significantly for the controls and MI patients (153 ± 124 pl/s vs 154 ± 125 pl/s, p = 0.84). This pilot iPhone and slit-lamp assessment of the conjunctival microcirculation found lower axial velocity and wall shear rate in patients with acute MI. Further study is required to correlate these findings further and assess long-term outcomes in this patient group with a severe CVD phenotype.

Bulbar Conjunctival Microvascular Alterations in Thyroid-Associated Ophthalmopathy Patients with Different Activities.

Purpose: To evaluate the morphologic and hemodynamic changes of bulbar conjunctival vessels in thyroid-associated ophthalmopathy (TAO) patients and the correlations with the activity.Methods: Patients diagnosed as TAO with different clinical activity scores (CAS) and healthy participants were recruited. All subjects underwent a complete ophthalmic examination and functional slit-lamp biomicroscope. Vascular variables including the vessel density, vessel complexity, average diameter, blood flow velocity and blood flow rate in microvascular networks were measured. The correlations among microvascular parameters, CAS and exophthalmos were analyzed. Areas under the receiver operating characteristic curves (AUROCs) were applied to evaluate the diagnostic accuracy of microvascular alterations for active TAO.Results: A total of 46 eyes were enrolled in our study. The vessel complexity and blood flow velocity increased in the active TAO group significantly compared with the inactive group and healthy controls (P < .05). Meanwhile, the vessel complexity and blood flow rate were positively correlated with CAS (r = 0.641 and r = 0.526). Bulbar conjunctival microvascular parameters performed a good ability in distinguishing the active stage of TAO (AUROC = 0.793).Conclusions: Increasing bulbar conjunctival vessel complexity and blood flow were evident in TAO with severe inflammation. The measurements of bulbar conjunctival microvasculature could be a reference to evaluate activity in TAO.