Retinal perfusion related to visual field within the same asymmetric thyroid-associated ophthalmopathy.

PURPOSE: To quantify interocular differences in the retinal microvasculature between disparate eyes and explore associations between the retinal microvasculature and visual field abnormalities within the same asymmetric thyroid-associated ophthalmopathy (TAO) patients. METHODS: Within the same asymmetric TAO eye, the eye with a severer visual field abnormality (based on the mean deviation [MD]) was considered a severe eye, and the fellow eye was considered mild. The densities of radial peripapillary capillary (RPC) and superficial retinal capillary plexuses (SRCP) were determined using optical coherence tomography angiography. Interocular differences in RPC and SRCP densities were analyzed. A generalized estimating equation (GEE) was used to form a predictive model for visual field abnormalities. Pearson's correlation was used to show the correlation between MD and the densities of RPC and SRCP. RESULTS: In 57 asymmetric TAO patients, the global RPC density in severe eyes was lower than that in mild eyes (P < 0.001), but there was no significant difference in SRCP density between the two groups (P = 0.114). In a multivariate GEE model with MD as the outcome, MD was associated only with global RPC density (coefficient ß=0.327, P < 0.001). The global RPC density was correlated with MD (r = 0.360, P = 0.003) in severe eyes, but not in mild eyes (r = 0.179, P = 0.092). No significant correlation was observed between global SRCP density and MD in either group (Both P > 0.05). CONCLUSIONS: RPC density decreased significantly and correlated with visual field abnormalities in severe eyes of TAO patients. Alterations in RPC density may contribute to visual field abnormalities in TAO eyes.

Decreased retinal capillary density as a beneficial response to 24-week high-speed circuit resistant training in healthy older adults.

PURPOSE: To determine the changes in retinal microvascular density after a 24-week high-speed circuit resistance training program (HSCT) in healthy older adults. METHODS: Thirty healthy older adults were recruited and randomly assigned to either a training group (HSCT) or a non-training (CON) group. Fifteen subjects (age 73.3 ± 7.76 yrs) in the HSCT group exercised three times per week on non-consecutive days for 24 weeks. Fifteen subjects in the CON group (age 72.2 ± 6.04 yrs) did not have formal physical training. Both eyes of each subject were imaged using optical coherence tomography angiography (OCTA) at baseline and at the 24-week follow-up. The vessel densities of the retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP) were measured. RESULTS: There were no demographic differences between the study groups. There were significant decreases in the retinal vessel densities of RVN, SVP and DVP in the HSCT group (P < 0.05). However, there were no significant changes in all three vascular measurements in the CON group (P > 0.05), although the changes showed a decreasing trend. The decreased vessel densities were doubled in the HSCT group in comparison to the CON group. However, the differences between groups did not reach a significant level (P > 0.05). CONCLUSIONS: This is the first study to reveal the decreased retinal vessel densities as a possible imaging marker for the beneficial effects of the 24-week HSCT program in older adults.

Association of retinal microvascular density and complexity with incident coronary heart disease.

BACKGROUND AND AIMS: The high mortality rate and huge disease burden of coronary heart disease (CHD) highlight the importance of its early detection and timely intervention. Given the non-invasive nature of fundus photography and recent development in the quantification of retinal microvascular parameters with deep learning techniques, our study aims to investigate the association between incident CHD and retinal microvascular parameters. METHODS: UK Biobanks participants with gradable fundus images and without a history of diagnosed CHD at recruitment were included for analysis. A fully automated artificial intelligence system was used to extract quantitative measurements that represent the density and complexity of the retinal microvasculature, including fractal dimension (Df), number of vascular segments (NS), vascular skeleton density (VSD) and vascular area density (VAD). RESULTS: A total of 57,947 participants (mean age 55.6 ± 8.1 years; 56% female) without a history of diagnosed CHD were included. During a median follow-up of 11.0 (interquartile range, 10.88 to 11.19) years, 3211 incident CHD events occurred. In multivariable Cox proportional hazards models, we found decreasing Df (adjusted HR = 0.80, 95% CI, 0.65-0.98, p = 0.033), lower NS of arteries (adjusted HR = 0.69, 95% CI, 0.54-0.88, p = 0.002) and venules (adjusted HR = 0.77, 95% CI, 0.61-0.97, p = 0.024), and reduced arterial VSD (adjusted HR = 0.72, 95% CI, 0.57-0.91, p = 0.007) and venous VSD (adjusted HR = 0.78, 95% CI, 0.62-0.98, p = 0.034) were related to an increased risk of incident CHD. CONCLUSIONS: Our study revealed a significant association between retinal microvascular parameters and incident CHD. As the lower complexity and density of the retinal vascular network may indicate an increased risk of incident CHD, this may empower its prediction with the quantitative measurements of retinal structure.

Retinal microvasculature alteration in patients with systemic sclerosis and chloroquine treatment.

Background: Retinal vascular abnormality is an important part of ocular systemic sclerosis (SSc), and long-term use of chloroquine can lead to retinal toxicity. This study was conducted to evaluate retinal microvascular changes using optical coherence tomography angiography (OCTA) in patients with SSc and SSc patients on long-term chloroquine treatment. Methods: Fifteen SSc patients without chloroquine (30 eyes), 15 SSc patients taking long-term chloroquine (30 eyes) and 15 healthy controls (30 eyes) were recruited to this cross-sectional study. OCTA was used to examine the superficial and deep retinal capillary plexus in the macular retina of each eye. The densities of microvessels (MIR), macrovessels (MAR) and total microvessels (TMI) in the superficial and deep retina of the three groups were calculated and compared. We used the hemisphere segmentation method [superior right (SR), superior left (SL), inferior left (IL), and inferior right (IR)] and Early Treatment Diabetic Retinopathy Study (ETDRS) method [right (R), superior (S), left (L), and inferior (I)] to analyze changes in retinal microvascular density. Results: The superficial and deep retinal MIR density in SSc patients decreased (P<0.05) compared with the healthy control group. This significant difference was found in both superficial and deep layers in S, L, SR, SL and IL regions (P<0.05), and additionally in the R and I regions in the superficial layer (P<0.05). Similarly, compared with SSc patients who did not take chloroquine, the superficial and deep retinal MIR density of SSc patients on long-term chloroquine also decreased (P<0.05). This significant difference was found in both superficial and deep layers in R, I and IL regions (P<0.05), and additionally in the IR region in the superficial layer (P<0.05). Conclusions: The OCTA results suggest that retinal MIR density is decreased in SSc patients, and that long-term use of chloroquine will aggravate this damage, resulting in a further decrease in retinal MIR density.

Ocular microvascular alteration in Sjögren syndrome.

BACKGROUND: Sjögren syndrome (SjS) is a systemic disease affecting exocrine, including ocular lacrimal, glands. It is uncertain whether ocular microvascular alterations are associated with this disease. In this study, we evaluated retinal and conjunctival microvascular changes in SjS patients using optical coherence tomography angiography (OCTA). METHODS: Twelve SjS patients (24 eyes) and 12 normal controls (24 eyes) were recruited to this study. Three-dimensional conjunctival and retinal OCTA images of each eye were captured and microvascular density was calculated. Each image was analyzed by retinal area based on the early treatment of diabetic retinopathy study method (R, S, L, and I) hemisphere segmentation method (SR, SL, IL, and IR); and central wheel division method (C1-C6). Correlation analyses were used to look for associations between retinal and conjunctival microvascular densities. RESULTS: Superficial and deep retinal layer microvascular density was decreased in SjS patients compared with normal controls (P<0.05). This significant difference was found in both superficial and deep layers in S, L, SL, IL and C1-C3 regions, and additionally in the I and SR regions in the superficial layer. Conversely, in the conjunctiva microvascular density was higher in SjS patients than in controls. In SjS patients, a significant negative correlation was found between conjunctival and both superficial (r=-0.641; P=0.025) and deep (r=-0.958; P<0.0001) microvascular densities. CONCLUSIONS: The changed microvascular densities measured in deep and superficial retinal layers and in the conjunctiva demonstrate that OCTA is a promising method in differentiating the eyes from those with SjS.

Visual Impairments Are Associated With Retinal Microvascular Density in Patients With Parkinson's Disease.

OBJECTIVE: This study aimed to evaluate retinal microvascular density in patients with Parkinson's disease (PD) and its correlation with visual impairment. METHODS: This cross-sectional study included 24 eyes of 24 patients with PD and 23 eyes of 23 healthy controls. All participants underwent ophthalmic examination, visual evoked potential (VEP) test, 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), and optical coherence tomography angiography (OCTA) examination. The correlation between retinal microvascular density and visual parameter was evaluated using Spearman correlation analysis, and the area under receiver operating characteristic curve (AUROC) was calculated. RESULTS: Parkinson's disease patients had prolonged P100 latency (P = 0.041), worse vision-related quality of life (composite score and 3 of 12 subscales in NEI VFQ-25), and decreased vessel density (VD) in all sectors of 3-mm-diameter region (all P < 0.05) compared with healthy controls. There were no statistical differences in the ganglion cell-inner plexiform layer (GCIPL) thickness and retinal nerve fiber layer (RNFL) thickness between the two groups. A negative correlation was found between P100 latency and nasal and superior sectors of macular VD in a 3-mm-diameter region (r = -0.328, P = 0.030; r = -0.302, and P = 0.047, respectively). Macular VD in a 3-mm-diameter region showed diagnostic capacities to distinguish PD patients from healthy controls (AUROCs, ranging from 0.655 to 0.723). CONCLUSION: This study demonstrated that decreased retinal microvascular density was correlated with visual impairment in PD patients. Retinal microvasculature change may occur earlier than visual decline and retinal structure change and has the potential to be a promising diagnostic marker for early PD.

Characterization of retinal microvasculature and its relations to cognitive function in older people after circuit resistance training.

PURPOSE: To characterize the changes of retinal microvascular density and their relations to cognitive function in the healthy older people without known cognitive impairment after an 8-week high-speed circuit resistance training program (HSCT). METHODS: Twenty cognitively normal older people were recruited and randomly assigned to either the HSCT group or control group (CON). Twelve subjects (age 70.8 ± 5.8 yrs) in the HSCT group trained three times per week for 8 weeks. Eight subjects in the CON group (age 71.8 ± 4.8 yrs) did not perform formal training. Both eyes of each subject were imaged using optical coherence tomography angiography (OCTA) at baseline and at 8-week follow-up. The densities of the retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP) were measured. In addition, their cognitive functions were tested using the NIH toolbox. RESULTS: There were significant increases in pattern comparison processing speed (PAT, P = 0.02) and fluid composite score (FCS, P = 0.005) at the follow-up in the HSCT group. Although the vessel densities did not differ between visits in either group, the variation (i.e., change) in retinal vessel density of SVP was negatively related to the changes of FCS (r = -0.54, P = 0.007) and the List Sorting Working Memory test (r = -0.43, P = 0.039) in the HSCT group. CONCLUSIONS: This is the first study to reveal that the individual response of the SVD was related to the improvement in the cognition in cognitively normal older people after HSCT.

Assessment of superficial retinal microvascular density in healthy myopia.

PURPOSE: To evaluate retinal microvasculature in healthy myopia and investigate the correlation between microvascular density and ocular factors. METHODS: A total of 174 eyes from 174 healthy Korean subjects were included. The eyes were divided into four groups according to refraction: emmetropia [21 eyes, - 1.00 D ≤ mean spherical equivalent (MSE) < + 0.75 D], mild myopia (32 eyes, - 3.00 D ≤ MSE < - 1.00 D), moderate myopia (76 eyes, - 6.00 D ≤ MSE < - 3.00 D), and high myopia (45 eyes, MSE < - 6.00 D). Images of retinal vasculature in parapapillary and parafoveal area were obtained using optical coherence tomography angiography. Superficial retinal microvascular density was measured for correlation analysis with ocular parameters. RESULTS: High myopia was found to have a lower superficial parapapillary microvascular density compared with the other groups in total parapapillary area, and in sectors of nasal and inferonasal (all p ≤ 0.001). The superficial parapapillary microvascular density showed a negative correlation with axial length (AL) and intraocular pressure (IOP) (ß = - 0.479, p = 0.008 and ß = - 0.160, p = 0.048, respectively), and a positive correlation with parapapillary retinal nerve fiber layer (RNFL) thickness (ß = 0.140, p < 0.001). However, there was no significant difference in superficial parafoveal microvascular density among all groups (p > 0.05). CONCLUSIONS: This study reveals that superficial parapapillary microvascular density is lower in high myopia and has correlation with AL, IOP, and parapapillary RNFL thickness. It also indicates that superficial parafoveal microvascular density tends to be unaffected by healthy myopia. These retinal microvascular alterations may facilitate understanding the pathogenesis of glaucomatous optic nerve damage in high myopia.