The effect of vitamin D deficiency on the retinal microvasculature: an observational case-control study / O efeito da deficiência de vitamina D nos microvasos da retina: um estudo caso-controle observacional

ABSTRACT Purpose: To determine the effects of vitamin D deficiency on retinal microvascularity using optical coherence tomography angiography. Methods: This study was designed as an observational case-control study. Ninety-eight eyes of patients with vitamin D deficiency and 96 eyes of healthy participants with serum vitamin D level >30 ng/mL were studied. Macula centered, 6.00 × 6.00 mm scan size images were taken. The vessel densities in the superficial and deep retinal capillary plexus, foveal avascular zone area, and choriocapillaris flow area were measured. Results: The groups were comparable in terms of best-corrected visual acuity, sex, axial length, refractive error, age, and adjusted intraocular pressure. The average vitamin D level was significantly lower in the study group (p=0.021). The whole, parafoveal, and perifoveal vessel densities in the deep capillary plexus were considerably higher in the study group than in the control group (p=0.012, p=0.014, and p=0.023, respectively). The foveal avascular zone area and the choriocapillaris flow area were similar in both groups (p=0.37 and p=0.27, respectively) there was a strong negative correlation between the serum vitamin D level and vessel density in the whole image, parafoveal, and perifoveal regions of the deep capillary plexus in the study group (Spearman's rho=-0.71, p=0.043; Spearman's rho= -0.79, p=0.011; and Spearman's rho = -0.74, p=0.032; respectively). Conclusion: An increase in vessel density might originate from vascular structural changes caused by vitamin D deficiency. The increased vessel density, especially in the deep capillary plexus, can enable early diagnosis of vitamin D-associated vasculopathy.

RESUMO Objetivo: Determinar os efeitos da deficiência de vitamina D nos microvasos da retina usando angiotomografia de coerência óptica. Métodos: Este estudo foi planejado para ser do tipo caso-controle observacional. Foram avaliados 98 olhos de pacientes com deficiência de vitamina D e 96 olhos de participantes saudáveis com nível sérico de vitamina D superior a 30 ng/mL. Foram adquiridas imagens de varredura centralizadas na mácula, com um tamanho de 6,00 × 6,00 mm. Mediram-se a densidade dos vasos nos plexos capilares superficial e profundo da retina, a área da zona avascular foveal e a área do fluxo coriocapilar. Resultados: Os grupos mostraram-se semelhantes em relação à melhor acuidade visual corrigida, ao gênero, ao comprimento axial, ao erro refrativo, à idade e à pressão intraocular ajustada. O nível médio de vitamina D foi significativamente menor no grupo de estudo (p=0,021). As densidades total, parafoveal e perifoveal do plexo capilar profundo foram significativamente maiores no grupo de estudo que no grupo controle (respectivamente, p=0,012, p=0,014 e p=0,023). As áreas da zona avascular foveal e do fluxo coriocapilar foram semelhantes nos dois grupos (respectivamente, p=0,37 e p=0,27). Além disso, houve uma forte correlação negativa do nível sérico de vitamina D com as densidades vasculares medidas em toda a imagem e nas regiões parafoveais e perifoveais do plexo capilar profundo no grupo de estudo (respectivamente, ρ de Spearman = −0,71, p=0,043; ρ de Spearman = −0,79, p=0,011; e ρ de Spearman = −0,74, p=0,032). Conclusão: Pode ocorrer um aumento na densidade vascular da retina devido a alterações estruturais dos vasos causadas pela deficiência de vitamina D. O aumento da densidade vascular, especialmente no plexo capilar profundo, pode ser usado para o diagnóstico precoce da vasculopatia associada à deficiência de vitamina D.

Evaluation of the retinal vasculature of patients with branch retinal vein occlusion using optical coherence tomography angiography / Avaliação da vasculatura da retina em pacientes com oclusão de ramo da veia central da retina utilizando a angiografia por tomografia de coerência óptica

ABSTRACT Purpose: To evaluate vascular density in super­ficial and deep capillary plexuses of the retina, measured using optical coherence tomography angiography in patients with branch retinal vein occlusion. Affected eyes were compared with the contralateral eye of the same patient and both were compared with normal eyes. Methods: A cross-sectional study including 16 previously untreated patients with branch retinal vein occlusion. Patients with poor quality examinations, bilateral disease, high refractive error, or any other retinal or choroidal disease were excluded. A total of 31 patients without eye disease were also selected as a comparison group. All participants underwent five optical coherence tomography angiographies, and only those with at least two good quality examinations were selected. The Kruskal-Wallis, Wilcoxon signed-rank, and Mann-Whitney U tests were used for the statistical analysis. Results: Vascular density was lower in affected eyes compared with contralateral eyes: whole density (p=0.020 for capillary plexuses superficial; p=0.049 for deep capillary plexuses) and parafoveal density (p=0.020 for capillary plexuses superficial; p=0.011 for deep capillary plexuses). Vascular density was also lower in affected eyes compared with normal eyes: whole density (p<0.001 for capillary plexuses superficial and deep) and parafoveal density (p<0.001 for capillary plexuses superficial and deep). Whole density (p=0.001 for capillary plexuses superficial and deep) and parafoveal density (p=0.001 for capillary plexuses superficial; p<0.001 for deep capillary plexuses) were both lower in the contralateral eyes compared with normal eyes. Following adjustment for arterial hypertension, this difference was no longer observed. Conclusions: Vascular density in capillary plexuses and deep capillary plexuses was lower in the eyes affected by branch retinal vein occlusion. Furthermore, the lower vascular density noted in the contralateral eyes indicates that changes most likely occurred in these eyes prior to the appearance of any clinically detectable alterations, reflecting the early signs of hypertensive retinopathy.

RESUMO Objetivo: Avaliar a densidade vascular do plexo capilar superficial e profundo da retina, usando angiografia por tomografia de coerência óptica em pacientes com oclusão de ramo da veia central da retina, comparando o olho afetado com o contralateral do mesmo paciente e ambos com olhos normais. Métodos: Estudo transversal. Incluídos dezesseis pacientes com oclusão de ramo da veia central da retina sem tratamento prévio. Pacientes com exames de baixa qualidade, altas ametropias, outras patologias de retina ou coróide foram excluídos. Para comparação, trinta e um pacientes sem doença ocular foram selecionados. Todos foram submetidos a cinco exames angiografia por tomografia de coerência óptica, apenas aqueles com pelo menos dois exames de boa qualidade permaneceram no estudo. Os testes Kruskal-Wallis, Wilcoxon, e Mann-Whitney foram utilizados. Resultados: Densidades vasculares mais baixas do plexo capilar superficial e plexo capilar profundo foram observadas quando olhos com oclusão de ramo da veia central da retina foram comparados com os contralaterais: densidade total (p=0,02 para plexo capilar superficial, p=0,049 para plexo capilar profundo), densidade parafoveal (p=0,02 para plexo capilar superficial, p=0,011 para plexo capilar profundo). Comparando olhos acometidos com olhos normais, também foram observadas densidades vasculares mais baixas de plexo capilar superficial e plexo capilar profundo: densidade total (ambos com p<0,001) e densidade parafoveal (ambos com p<0,001). Quando os olhos contralaterais foram comparados aos normais, tanto a densidade total do plexo capilar superficial e plexo capilar profundo (ambos com p=0,001) quanto a densidade parafoveal (plexo capilar superficial com p=0,001, plexo capilar profundo com p<0,001) foram menores. Ao se realizar uma subanálise, minimizando o fator hipertensão arterial, esta diferença não se manteve. Conclusões: Densidades vasculares mais baixas do plexo capilar superficial e do plexo capilar profundo foram observadas em olhos com oclusão de ramo da veia central da retina. Além disso, a presença de densidades vasculares mais baixas nos olhos contralaterais mostra que já existem altera­ções nesses olhos antes das alterações clínicas, devido a al­terações inicias da retinopatia hipertensiva.

The correlation of oxygen saturation of retinal vessels and diabetic retinopathy stages or HbA1c levels in ;patients with diabetic retinopathy / 中华眼底病杂志

Objective To evaluate the correlation of oxygen saturation of retinal vessels and diabetic retinopathy (DR) stages or HbA1c level in patients with DR. Methods Cross sectional study. A total of 102 patients (102 eyes) with DR and 20 age-matched healthy controls (20 eyes) (normal control group) were enrolled in this study. DR patients were divided into mild and moderate non-proliferative DR (NPDR) group (55 patients), severe NPDR group (26 patients) and proliferative DR (PDR) group (21 patients). DR patients were also divided into 3 groups according to the HbA1c level including HbA1c>9%(8 patients), HbA1c 7%–9%(33 patients) and HbA1c9%group were significantly higher than that in HbA1c 7%–9%group and HbA1c9%, HbA1c 7%0.05). Conclusions The retinal artery and vein oxygen saturation in DR patients are related to the DR stages. Severe NPDR patients show the highest retinal artery oxygen saturation as well as biggest difference between retinal artery and vein oxygen saturation. There is also a trend that retinal vein oxygen saturation increases with higher DR stages. In addition, there is a positive correlation between the levels of HbA1c and retinal vessel oxygen saturation.

Protection of sericin to retinal microvessels and its mechanism in diabetic rats / 中华实验眼科杂志

Background Diabetic retinopathy (DR) is a chronic inflammatory disease,with pathological changes of retinal microvessels.Studies demonstrated that sericin has anti-inflammation and anti-oxidation effects,inferring that sericin might play a protective effect on diabetic microangiopathy.Objective This study was to investigate the effects of sericin on intercellular adhesion molecule-1 (ICAM-1),vascular cell adhesion molecule-1 (VCAM-1) and Cx43 expressions in retina and explore the protection of sericin to retinal microangiopathy in diabetic rats.Methods Forty-eight specific pathogen free male SD rats were randomly divided into normal control group,diabetic model group,sericin-treated group and calcium dobesilate-treated group,with 12 rats for each group.The diabetic models were established by intraperitoneal injection of streptozotocin (STZ) for 3 consecutive days and feeding up with high lipid foods.Normal saline solution,2.4 g/(kg · d) sericin solution and 0.2 g/(kg · d) calcium dobesilate were used by gavage administration in the rats of the diabetic model group,sericin-treated group and calcium dobesilate-treated for 3 months group,respectively.The rats were sacrificed and retinal sections were prepared,and the retinal morphology was examined by hematoxylin-eosin staining.The expressions of ICAM-1,VCAM-1 and Cx43 proteins and mRNA in retinas were detected by Western blot assay and reverse transcription PCR.The use and care of the rats complied with Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission and ARVO statement.Results The retinal structure was normal in the normal control group.The swell and rupture of inter limiting membrane (ILM),scatter vascular endothelial cell nuclei breakthrough ILM and decrease of retinal ganglion cells (RGCs) were displayed in the diabetic model group;while in the sericin-treated group and calcium dobesilate-treated group,the mild thickening of ILM and disorder of retinal cells were obtained.The relative expression levels of ICAM-1 and VCAM-1 were significantly raised and those of Cx43 were reduced in the diabetic model group,sericin-treated group and calcium dobesilate-treated group when compared with the normal control group (all at P＜0.05).Compared with the diabetic model group,the expressions of ICAM-1 and VCAM-1 proteins and mRNA in the sericin-treated group were significantly reduced (ICAM-1 protein:0.834 3±0.032 1 vs.0.918 9±0.042 4;VCAM-Ⅰ protein:0.726 4±0.011 2 vs.1.235 0±0.078 9;ICAM-1 mRNA:0.716 3±0.008 6 vs.0.956 8±0.012 5;VCAM-1 mRNA:0.393 7±0.035 0 vs.0.477 9±0.020 6) and those of Cx43 protein and mRNA were evidently elevated (Cx43 protein:0.133 1 ±0.015 3 vs.0.039 2±0.002 0;Cx43 mRNA:0.676 8 ±0.064 8 vs.0.430 8±0.111 3) (all at P＜0.05).Conclusions Sericin can relieve retinal microangiopathy and protect retina against the pathogenesis and development of DR by down-regulating the expressions of ICAM-1,VCAM-1 and upregulating the expression of Cx43 in retinas of diabetic rats.

Relation between retinal vessel diameters and carotid artery stenosis patients with cerebral infarction / 中华眼底病杂志

Objective To investigate the relationship between retinal vessel diameters and cerebral infarction of carotid artery stenosis patients.Methods Eighty seven patients (174 eyes) with carotid stenosis were included in this study.There were 49 males and 38 females,with an average age of (65.25±7.85) years.Thirty-four patients were suffered from cerebral infarction (cerebral infarction group),and the other 53 patients had no cerebral infarction (control group).There was no significant difference in age (t=1.916),male rate (x2=0.142) and carotid stenosis extent (x2=0.785) between the two groups (P=0.059,0.706,0.675).All patients underwent color fundus photography after mydriasis.Retinal vascular caliber measurements were performed using IVAN software.The main parameters were central retinal artery diameter (central retinal artery equivalent,CRAE),the diameter of the central retinal vein (central retinal vein equivalent,CRVE) and the retinal arteriole to venular ratio (AVR).The relationship between retinal vessel diameter and cerebral vascular disease were analyzed with logistic regression analysis.Results In cerebral infarction group,CRVE,CRAE and AVR ratios were (132.90 ± 20.67) μm,(243.47 ±43.92) μm and 0.56±0.10,while the control group was (145.26±21.59) μm,(224.99±32.35) μm and 0.68±0.13 respectively.There were significant differences between the two groups (t=-2.648,2.257,-4.631;P＜0.05).After correction for risk factors,such as age,smoking history,CRAE reduction and CRVE increases were significantly correlated with cerebral infarction.Conclusion CRAE reduction and CRVE increases are risk factors of cerebral infarction in patients with carotid stenosis,and it is useful in the prediction.

Correctly understanding the clinical value of optical coherence tomography angiography / 中华实验眼科杂志

OCT angiography (OCTA) is a non-invasive imaging technique for detecting blood flow information of the retina and choroid.Dye injection is not needed with OCTA,which is different from fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA).OCTA is able to observe blood flow in different retinal and choroidal segmentation slab.This revolutionary breakthrough in OCTA algorithm provides more and more accurate blood flow informations in the diagnosis of ocular vessel diseases and the study on pathogenesis of some vessel-related eye diseases.However,like other biometric technology,OCTA has its limitations and shortcomings,for example,OCTA presents a smaller observational area than FFA and ICGA,and some factors affect the imaging quality and cause misdiagnosis during the examination and reading image.Fully understanding the principle of OCTA and its image features are helpful for eye doctors to better interpret the blood flow changes of retinal diseases,choroidal diseases,glaucoma and neuro-ophthalmic diseases.Ophthalmologists should correctly apply this imaging tool for a better monitoring and following up of these diseases.

Retinal vascular characteristics and the strategy to manage retinal vascular diseases / 中华眼底病杂志

The retinal vessel changes are the primary and major features of retinal vascular diseases.The retinal vessel is part of systemic vessels with its own characteristics to sustain normal retinal function.These basic characteristics are important to the correct understanding and proper treatment of retinal vascular diseases.Always keep in mind that the retinal vessels is one part of the systemic vascular system,thus retinal vascular diseases may have systemic etiology,and systemic drug administration may have a profound effects to the whole body.However retinal vascular system also has its own structural and functional characteristics,thus retinal vascular diseases are also different from the systemic diseases.Finally the main function of retinal vascular network is to maintain the neuro-retinal function,thus we should balance the vision protection and treatments against abnormal retinal blood vessels.Over-treatments may damage the retinal vision.

Relationship between endothelin and nitric oxide in plasma with retinopathy in the pregnancy-induced hypertension / 中华眼底病杂志

Objective To explore the effect of endothelin (ET)、nitric oxide (NO) in plasma on retinopathy in the pregnancy-induced hypertension (PIH). Methods The level of ET and NO in plasma of 75 cases of in-patient women with PIH and 20 cases of women with the full terms and normal pregnancy before and after delivery was determined by radioimmunoassay. The retinopathy of the patients with PIH before and after delivery was detected by appointed doctor. The levels of ET and NO in both groups were compared and the relationship between ET and NO in plasma and the retinopathy before and after the delivery was detected. Results The levels of ET [(145.00?54.41) ng/L] in serious PIH patients were much higher than that in the control [(81.50?43.80) ng/L], the minor [(85.30?33.33) ng/L] and middling PIH group [(90.20?39.25) ng/L]. The levels of ET in plasma before and after pregnancy were not changed in PIH patients [(118.70?33.44) ng/L], but were higher than that in the control group. The levels of plasma NO in serious [(87.56?35.58) ng/L] and middling [(78.11?28.96) ng/L] PIH group were both higher than that in the control group [(46.70?32.64) ng/L], and the levels in minor[(52.56?28.35) ng/L] and middling PIH group were lower than that in the serious PIH group. The level of NO in plasma of PIH patients after the delivery was much lower than that before the delivery, while higher than that in the control. The positive correlation between levels of ET and NO and retinopathy was found in PIH patients. Conclusions The levels of plasma ET and NO in PIH patients are related to the extent of the disease, and the level of ET in plasma is highly related to the retinopathy in PIH patients. ET and NO might be played an important role in pathogenesis of retinopathy and ET might be a good index in reflecting the rank of retinopathy in PIH.