Evaluation of optical coherence tomography angiography metrics in children and adolescents with type 1 diabetes: 4-year longitudinal study.

PURPOSE: To evaluate longitudinal changes in optical coherence tomography angiography (OCTA) metrics in children and adolescents with type 1 diabetes (T1D). METHODS: This prospective observational cohort study included thirty-two eyes from thirty T1D children with no history of diabetic retinopathy (DR) who were followed up for 4 years. Participants underwent OCTA examinations at baseline and during follow-up. Quantitative OCTA metrics were measured using a customized MATLAB algorithm. Generalized mixed-effect models were used to determine their relationship with DR development. Systemic parameters and OCTA metrics were screened using least absolute shrinkage and selection operator to identify predictors for visual function. RESULTS: Over the 4-year period, seven of the included eyes developed DR, and most OCTA metrics decreased with diabetes duration. Higher peripapillary and parafoveal nasal quadrant vessel area density (VAD) in the superficial capillary plexus (SCP) and vessel skeleton density (VSD) in both the SCP and the deep capillary plexus (DCP) were associated with a lower risk of DR in T1D. Parafoveal DCP VSD and VAD in the temporal and inferior quadrants were anticorrelated with changes in best corrected visual acuity. CONCLUSIONS: OCTA metrics dynamically change over the duration of diabetes and can be used as biomarkers to improve the risk evaluation of DR development and visual function in T1D children and adolescents.

TCERG1L hypermethylation is a risk factor of diabetic retinopathy in Chinese children with type 1 diabetes.

AIM: To identify the differential methylation sites (DMS) and their according genes associated with diabetic retinopathy (DR) development in type 1 diabetes (T1DM) children. METHODS: This study consists of two surveys. A total of 40 T1DM children was included in the first survey. Because no participant has DR, retina thinning was used as a surrogate indicator for DR. The lowest 25% participants with the thinnest macular retinal thickness were included into the case group, and the others were controls. The DNA methylation status was assessed by the Illumina methylation 850K array BeadChip assay, and compared between the case and control groups. Four DMS with a potential role in diabetes were identified. The second survey included 27 T1DM children, among which four had DR. The methylation patterns of the four DMS identified by 850K were compared between participants with and without DR by pyrosequencing. RESULTS: In the first survey, the 850K array revealed 751 sites significantly and differentially methylated in the case group comparing with the controls (|Δß|>0.1 and Adj.P<0.05), and 328 of these were identified with a significance of Adj.P<0.01. Among these, 319 CpG sites were hypermethylated and 432 were hypomethylated in the case group relative to the controls. Pyrosequencing revealed that the transcription elongation regulator 1 like (TCERG1L, cg07684215) gene was hypermethylated in the four T1DM children with DR (P=0.018), which was consistent with the result from the first survey. The methylation status of the other three DMS (cg26389052, cg25192647, and cg05413694) showed no difference (all P>0.05) between participants with and without DR. CONCLUSION: The hypermethylation of the TCERG1L gene is a risk factor for DR development in Chinese children with T1DM.

Three-year follow-up study investigating changes in retinal vascular morphology and the relationship with diabetic retinopathy in children with type 1 diabetes mellitus.

INTRODUCTION: This study aimed to investigate changes in retinal microvascular morphology and associated factors, and their relationship with diabetic retinopathy (DR) in children with type 1 diabetes mellitus (T1DM). METHODS: Thirty-eight children enrolled in this three-year follow-up study underwent complete ophthalmic examinations including fundus photography. Retinal vascular parameters were measured automatically and compared between baseline and follow-up. Multiple linear regression was used to investigate factors affecting changes in vascular parameters. Binary logistic regression was used to analyze the relationship between retinal microvascular morphology and DR. RESULTS: The caliber of all retinal vessels (within 1-1.5 papillary diameter [PD] from the center of the optic disc, P = 0.030; 1.5-2 PD, P = 0.003), arterioles, and venules (1.5-2 PD, P = 0.001) were narrower in nearly all regions in the follow-up group compared with the baseline group. Vascular tortuosity increased in the central part of the retina and decreased in the periphery. The density (1-1.5 PD, P = 0.030) and fractal dimension (P = 0.037) of retinal vessels were increased at the end of the follow-up compared with baseline. Retinal vascular caliber was independently correlated with DR (odds ratio 0.793 [95% confidence interval 0.633-0.993]; P = 0.044). CONCLUSION: Retinal microvascular morphology in children with T1DM varied with the disease course. Narrower retinal vessels may be an independent risk factor for DR. Results of this study emphasized the importance of regular follow-up of fundus vascular morphology for the detection of early DR in children with T1DM.

A two-year longitudinal observational study of the peripapillary microvasculature in pediatric type 1 diabetes mellitus patients without visual impairment or diabetic retinopathy.

•Neurodegeneration precede microcirculatory deterioration in DR. Early signs can be seen in DM patients without visible DR symptoms, such as glial cell apoptosis and thinner retinal nerve fiber layer.•Peripapillary microvascular abnormalities in the peripapillary region may affect the normal metabolism of neurons and eventually aggravate the process of DR.•Prompting ongoing research to monitor the peripapillary microcirculation and microvasculature among T1DM children for early detection and prevention.•In longitudinal observation, the vessel density of the peripapillary superficial capillary plexus were slightly affected, while vessel density, blood flow, vessel morphological abnormalities and flow impairment area were significantly deteriorated in the deep capillary plexus.•The peripapillary deep capillary plexus is more susceptible and vulnerable to DR progression and could be used as a target for DR screening.

Study on the correlation between iris blood flow, iris thickness and pupil diameter in the resting state and after pharmacological mydriasis in patients with diabetes mellitus.

BACKGROUND: To investigate whether iris blood flow and iris thickness at the iris smooth muscle region affect the pupil diameter at rest and after drug-induced mydriasis in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). METHODS: T1DM patients and healthy children were recruited from the SCADE cohort. T2DM patients and healthy adults were recruited from patients undergoing cataract surgery at Shanghai General Hospital. Iris vessel density, pupil diameter (PD) and iris thickness were measured in both the resting and drug-induced mydriasis states. Iris vessel density was measured by optical coherence tomography angiography (OCTA), PD was measured by a pupilometer, and iris thickness at the iris smooth muscle regions were measured using anterior segment optical coherence tomography (AS-OCT). RESULTS: The study included 34 pediatric T1DM patients and 50 adult T2DM patients, both groups without diabetic retinopathy, and age-sex-matched healthy controls. At baseline, T1DM children and healthy children showed no differences in iris blood flow, iris thickness, or PD. However, the adult T2DM group exhibited higher vessel density at the pupil margin, thinner iris thickness at the iris dilator region, and smaller PD compared to healthy adults, with these differences being statistically significant (P < 0.05). After pupil dilation, there were no changes in iris blood flow and PD in the T1DM group compared to healthy children, whereas the T2DM group showed a significantly smaller PD compared to healthy adults. Multivariate regression analysis revealed that in the T2DM group, glycated hemoglobin was an independent factor of PD after dilation (ß=-0.490, p = 0.031), with no such factors identified in the T1DM group. CONCLUSION: The insufficiently dilated pupil diameter after drug-induced mydriasis is correlated to the level of glycated hemoglobin among T2DM patients. TRIAL REGISTRATION: The registration number on the clinical trial website was NCT03631108.

Sympathetic nervous system activity is associated with choroidal thickness and axial length in school-aged children.

BACKGROUND/AIMS: We aim to explore the effect of sympathetic nervous system (SNS) on choroid thickness (ChT) and axial length (AL). METHODS: Students of grade 2 and 3 from a primary school were included and followed for 1 year. Visual acuity, refraction, AL and ChT were measured. Morning urine samples were collected for determining SNS activity by analysing concentrations of epinephrine, norepinephrine and dopamine using the liquid chromatography-tandem mass spectrometry. The most important factor (factor 1) was calculated using factor analysis to comprehensively indicate the SNS activity. RESULTS: A total of 273 students were included, with an average age of 7.77±0.69 years, and 150 (54.95%) were boys. Every 1 µg/L increase in epinephrine is associated with 1.60 µm (95% CI 0.30 to 2.90, p=0.02) decrease in average ChT. Every 1 µg/L increase in norepinephrine is associated with 0.53 µm (95% CI 0.08 to 0.98, p=0.02) decrease in the ChT in inner-superior region. The factor 1 was negatively correlated with the ChT in the superior regions. Every 1 µg/L increase in norepinephrine was associated with 0.002 mm (95% CI 0.0004 to 0.004, p=0.016) quicker AL elongation. The factor 1 was positively correlated with AL elongation (coefficient=0.037, 95% CI 0.005 to 0.070, p=0.023). CONCLUSIONS: We hypothesised that chronic stress characterised by elevated level of the SNS, was associated with significant increase in AL elongation, probably through thinning of the choroid.

Metagenomic analysis of microbiological changes on the ocular surface of diabetic children and adolescents with a dry eye.

BACKGROUND: Microbiome changes on the ocular surface may cause dry eyes. A metagenome assay was used to compare the microbiome composition and function of the ocular surface between diabetic children and adolescents with dry eye, diabetic children and adolescents without dry eye, and normal children. MATERIALS AND METHODS: Twenty children and adolescents aged 8 to 16 with diabetes were selected from the Shanghai Children and Adolescent Diabetes Eye Study. Ten healthy children and adolescents belonging to the same age group were selected from the outpatient clinic during the same period. The participants were classified into the dry eye group (DM-DE group, n = 10), the non-dry eye group (DM-NDE group, n = 10) and the normal group (NDM group, n = 10). A conjunctival sac swab was collected for metagenomic sequencing, and the relationship between the microbiome composition and functional gene differences on the ocular surface with dry eye was studied. RESULTS: The classification composition and metabolic function of the microorganisms on the ocular surface of children in the 3 groups were analyzed. It was found that children's ocular microbiota was composed of bacteria, viruses and fungi. There were significant differences in α diversity and ß diversity of microbial composition of ocular surface between DM-DE group and NDM group(P<0.05). There were significant differences in α and ß diversity of metabolic pathways between the two groups(P<0.05). The functional pathways of ocular surface microorganisms in diabetic children with dry eyes were mainly derived from human disease, antibiotic resistance genes, carbohydrate, coenzyme and lipid transport and metabolism-related functional genes; In normal children, the functional pathways were mainly derived from replication, recombination, repair, signal transduction and defense-related functional genes. CONCLUSION: The DM-DE group have unique microbial composition and functional metabolic pathways. The dominant species and unique metabolic pathways of the ocular surface in the DM-DE group may be involved in the pathogenesis of dry eye in diabetic children.

Discrepancies in Vessel Density and Blood Flow Distribution in Different Areas of the Iris among Pediatric Type 1 Diabetes Mellitus and Adult Type 2 Diabetes Mellitus Patients.

INTRODUCTION: Diabetes mellitus may compromise the vasculature of the iris, thereby leading to severe vision-threatening complications. This study aimed to investigate differences in iris blood flow indices between pediatric type 1 diabetes mellitus (T1DM) patients and adult type 2 diabetes mellitus (T2DM) patients. METHODS: This was a cross-sectional study. Pediatric T1DM patients and healthy children were members of the Shanghai Children and Adolescent Diabetes Eye (SCADE) cohort who visited Shanghai Eye Hospital in February 2022. The adult T2DM patients and healthy adults were patients who visited Shanghai General Hospital from October 2021 to January 2022. Iris OCTA was acquired through a Cirrus HD-OCT 5000 angiography system (Carl Zeiss Meditec, Inc.). A unique iris OCTA quantification method was used, and the vessel area density (VAD) and vessel skeleton density (VSD) were obtained. The area from the pupillary margin to the corneoscleral limbus was taken as the whole iris blood flow index, and the inner third near the pupillary margin of the whole iris was taken as the pupillary margin blood flow index. RESULTS: This study enrolled 34 pediatric T1DM patients, 34 age-matched healthy children, 34 adult T2DM patients, and 34 age-matched healthy adults. The whole iris and pupillary margin VAD and VSD of the pediatric T1DM patients were not different from those of healthy children. The whole iris VAD and VSD of the adult T2DM patients were lower than those of healthy adults, and the pupillary margin VAD and VSD were the same in these two groups. Compared with adult T2DM patients, pediatric T1DM patients had higher whole iris VAD and VSD and lower pupillary margin VAD and VSD values, all with statistical significance. Among diabetic patients, age, BMI, and glycated hemoglobin level were negative independent influencing factors for whole iris VAD and VSD, and age was a positive influencing factor for pupillary margin VAD and VSD. CONCLUSION: There are diverse alterations in iris vessel density and blood flow distribution between pediatric T1DM patients and adult T2DM patients.

Combination of iris vessel area density and surgery interval as the predictor of perceived pain during consecutive second-eye cataract surgery.

PURPOSE: To explore clinical indicators to predict perceived pain during second-eye phacoemulsification surgery in patients with bilateral cataracts. SETTING: Shanghai General Hospital, China. DESIGN: A case‒control study and a prospective cohort study. METHODS: Patients with age-related cataract who underwent first-eye or second-eye uneventful phacoemulsification surgery were enrolled. Before surgery, ocular examination results, including vessel area density (VAD) and vessel skeleton density (VSD), obtained by optical coherence tomography angiography examination of the iris were performed. Patients completed a visual analog scale pain survey 3 times postoperatively: 1 hour, 3 hours, and 24 hours postoperatively. RESULTS: 70 patients were enrolled in the case‒control study, and the pain scores of the second-eye surgery group under local anesthesia were significantly greater than those of the first-eye surgery group ( P = .0005). Preoperative iris VAD in the second-eye group affected perioperative pain scores ( P = .0047). The optimal cutoff value of VAD was 0.2167 with a specificity of 76% and a sensitivity of 62%. In the prospective cohort study, 124 patients were included in the second-eye group. Preoperative iris VAD ( P = .0361) and the time interval ( P = .0221) were independent factors for second-eye surgery pain. Combined with preoperative iris VAD and surgical interval, the negative predictive value and positive predictive value were 0.95 and 0.29 for predicting moderate pain or above, the sensitivity and specificity were 0.97 and 0.23, respectively. CONCLUSIONS: The combination of iris VAD and the time interval between both eye surgeries can be an effective method to predict the timing of the second-eye cataract surgery and to avoid intraoperative pain.

Significantly different results in the ocular surface microbiome detected by tear paper and conjunctival swab.

BACKGROUND: Great variation has been observed in the composition of the normal microbiota of the ocular surface, and therefore, in addition to differences in detection techniques, the method of collecting ocular surface specimens has a significant impact on the test results.The goal of this study is to ascertain whether the eye surface microbial communities detected by two different sampling methods are consistent and hence explore the feasibility of using tear test paper instead of conjunctival swabs to collect eye surface samples for microbial investigation. MATERIALS AND METHODS: From July 15, 2021, to July 30, 2021, nonirritating tear test strips and conjunctival swabs of both eyes were used in 158 elderly people (> 60 years old) (79 diabetic and 79 nondiabetic adults) in Xinjing Community for high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The composition of the microbial communities in tear test paper and conjunctival swab samples was analyzed. RESULTS: There was no statistically significant difference in Alpha diversity of ocular surface microorganisms represented by tear strip and conjunctival swab in diabetic group (P > 0.05), but there was statistically significant difference in Alpha diversity of ocular surface microorganisms detected by tear strip and conjunctival swab in nondiabetic group (P < 0.05). There were statistically significant differences in Beta diversity of ocular surface microorganisms detected by two sampling methods between diabetic group and nondiabetic group (P < 0.05). There were statistically significant differences in ocular surface microorganisms detected by tear strip method between diabetic group and nondiabetic group (P < 0.05), but there was no statistically significant difference in conjunctival swab method (P > 0.05). CONCLUSIONS: Tear test paper and conjunctival swabs detect different compositions of microbes through two different techniques of eye surface microbe sampling. Tear test paper cannot completely replace conjunctival swab specimens for the study of microbes related to eye surface diseases.

Microbiological Characteristics of Ocular Surface Associated With Dry Eye in Children and Adolescents With Diabetes Mellitus.

Purpose: To analyze the characteristics of ocular surface microbial composition in children and adolescents with diabetes mellitus and dry eye (DE) by tear analysis. Methods: We selected 65 children and adolescents aged 8 to 16 years with DE and non-DE diabetes mellitus and 33 healthy children in the same age group from the Shanghai Children and Adolescent Diabetes Eye Study. Tears were collected for high-throughput sequencing of the V3 and V4 region of 16S rRNA. The ocular surface microbiota in diabetic DE (DM-DE; n = 31), diabetic with non-DE (DM-NDE; n = 34), and healthy (NDM; n = 33) groups were studied. QIIME2 software was used to analyze the microbiota of each group. Results: The DM-DE group had the highest amplicon sequence variants, and the differences in α-diversity and ß-diversity of micro-organisms in the ocular surfaces of DM-DE, diabetic with non-DE, and healthy eyes were statistically significant (P < 0.05). Bacteroidetes (15.6%), Tenericutes (9.3%), Firmicutes (21.8%), and Lactococcus (7.9%), Bacteroides (7.8%), Acinetobacter (3.9%), Clostridium (0.8%), Lactobacillus (0.8%) and Streptococcus (0.2%) were the specific phyla and genera, respectively, in the DM-DE group. Conclusions: Compared with the patients with non-DE and healthy children, the microbial diversity of the ocular surface in children and adolescents with diabetes mellitus and DE was higher with unique bacterial phyla and genera composition.

Quantitative changes in iris and retinal blood flow after femtosecond laser-assisted in situ keratomileusis and small-incision lenticule extraction.

Purpose: To investigate the quantitative changes in iris and retinal blood flow indices after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small-incision lenticule extraction (SMILE). Methods: Seventy-nine patients who underwent FS-LASIK or SMILE were enrolled between July 2020 and September 2020. Participants were followed-up 1 day pre-operatively and 1 week, 1 month, 3 months post-operatively. Optical coherence tomography angiography (OCTA) was used to acquire and quantify the iris and retinal blood flow indices. Results: The iris vessel area density (VAD) and vessel skeleton density (VSD) decreased on post-operative day 1 but recovered on day 7. In both cases, the pupil diameter was positively associated with the post-operative iris blood flow indices (p = 0.0013, p = 0.0002). The retinal VAD and VSD in the superficial and deep capillary plexuses decreased after surgery and failed to recover after 90 days. The SMILE group showed significantly lower iris and retinal blood flow indices than the FS-LASIK group. For both procedures, axial length (p = 0.0345, p = 0.0499), spherical equivalence (p = 0.0063, p = 0.0070), and suction duration (p = 0.0025, p = 0.0130) were negatively correlated with the post-operative VAD and VSD. Conclusions: The SMILE and FS-LASIK procedures induced a short-term decrease in the iris and retinal blood flow indices, although patients finally showed full visual recovery. This phenomenon should be carefully considered, especially in patients prone to anterior segment lesions.

Increased serum 12-hydroxyeicosatetraenoic acid levels are correlated with an increased risk of diabetic retinopathy in both children and adults with diabetes.

PURPOSE: To investigate the relationship between serum 12-Hydroxyeicosatetraenoic acid (12-HETE) and diabetic retinopathy (DR) in children with type 1 diabetes mellitus (T1DM) and adults with type 2 diabetes mellitus (T2DM). METHODS: Children from the Shanghai Children and Adolescent Diabetes Eye (SCADE) study and adults from the Shanghai Cohort Study of Diabetic Eye Disease (SCODE) were examined in 2021. Serum 12-HETE levels were detected and compared. Multivariate logistic regression was used to analyze the relationship between 12-HETE and the rate of DR in diabetic patients. RESULTS: The child study included 4 patients with new-onset DR and 24 patients with T1DM without DR. In children with T1DM, the 12-HETE level was significantly higher in those with DR (P = 0.003). The adult study had two sets, for testing and verification. The test set included 28 patients with new-onset DR and 24 T2DM patients with a course of ≥ 20 years who had never developed DR. The verification set included 41 patients with DR, 50 patients without DR and 50 healthy controls. In the adult test set, the 12-HETE level was significantly higher in patients with DR than in those with T2DM without DR (P = 0.003). In the verification set, the 12-HETE level of patients with DR was significantly higher than that of patients without DR (P < 0.0001) and the healthy controls (P < 0.0001). Multivariate logistic regression indicated that 12-HETE was independently associated with DR in both children (odds ratio [OR] 1.06, 95% confidence interval [CI] 1.00-1.13, P = 0.041) and adults (test set [OR 9.26, 95% CI 1.77-48.59, P = 0.008], verification set [OR 10.49, 95% CI 3.23-34.05, P < 0.001]). CONCLUSION: Higher serum 12-HETE levels are positively correlated with an increased risk of DR in children with T1DM and adults with T2DM.

Two-year longitudinal study on changes in thickness of the retinal nerve fiber layer and ganglion cell layer in children with type 1 diabetes mellitus without visual impairment or diabetic retinopathy.

PURPOSE: To study changes in the thickness of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) in children with type 1 diabetes mellitus (T1DM) without visual impairment or diabetic retinopathy (DR) after 2 years of follow-up and analyze the associated factors. METHODS: Thirty-seven children with T1DM were enrolled in this study. All children underwent a complete ophthalmologic evaluation that included swept-source optical coherence tomography at baseline and follow-up. Changes in RNFL and GCL thickness were compared among the children at baseline and follow-up. RESULTS: The peripapillary RNFL thickness was greater in the temporal (inner, p = 0.015; outer, p = 0.004) and inner superior (p = 0.043) sectors in the follow-up group than in the baseline group. The macular RNFL thickness in the fovea, inner nasal sector, inner inferior sector, and outer ring and the average thickness (all p < 0.05) were greater in the follow-up group than in the baseline group. The peripapillary GCL thickness decreased in the temporal sector (inner, p = 0.049; outer, p = 0.041) and increased in the inner nasal sector (p = 0.006) in the follow-up group compared with the baseline group, and the thickness of the inner temporal, inner superior, inner inferior, outer nasal, and outer inferior sectors and average thickness in the macula were lower in the follow-up group than in the baseline group (all p < 0.05). The total retinal thickness around optic disc in the follow-up group increased in the inner superior sectors (p = 0.006). The total retinal thickness of the macula decreased in inner temporal sector, inner superior sector and outer nasal sector, and increased in outer superior sector (all p < 0.05). CONCLUSIONS: Retinal neurodegenerative changes preceded microvascular changes in children with T1DM in the early stage. Peripapillary RNFL thickness in the nasal sector may be lower in children with T1DM without visual impairment or other ocular pathologies.

Incidence and Risk Factors of Dry Eye in Children and Adolescents With Diabetes Mellitus: A 3-Year Follow-Up Study.

Purpose: To investigate the incidence and risk factors of dry eye in children with diabetes mellitus (DM) over a period of 3 years. Methods: Children and adolescents with DM (age: 3-14 years) from the Shanghai Children and Adolescent Diabetes Eye (SCADE) study cohort who did not have dry eye in January 2018 were followed-up for 3 years and re-examined in January 2021, and the incidence rate and risk factors for dry eye were calculated. Results: Forty children and adolescents with DM came for follow-up in 2021. Nine of them were diagnosed with dry eye, resulting in a 3-year incidence rate of 22.5% and an annual mean incidence rate of 7.5% for dry eye. Univariate regression analysis confirmed that decreased corneal sensation (OR [Odds Ratio] = 25.60; 95%CI [Confidence Interval] = 1.31~501.69; P = 0.03) was the risk factor for dry eye incidence. Long course of DM (OR = 1.80; 95%CI = 0.96~3.38; P = 0.07), eye pain (OR = 12.27; 95%CI = 0.65~231.48; P = 0.09), and dry eye in parents (OR = 15.99; 95%CI = 0.76~337.75; P = 0.08) may interfere with the incidence of dry eye in them. Conclusions: The incidence of dry eye in children and adolescents with DM is high.

Quantitative analysis and clinical application of iris circulation in ischemic retinal disease.

BACKGROUND: To evaluate quantitative changes in iris blood circulation in patients with ischemic risk. METHODS: This observational case-control study included 79 patients with diabetic retinopathy (DR) and retinal vein occlusion (RVO). The RVO group included 21 patients; the monocular proliferative diabetic retinopathy (PDR) group included 19 patients; the nondiabetic retinopathy (NDR) group included 18 patients; and the healthy control group included 21 healthy controls. In the RVO group, we analyzed RVO affected eyes, RVO contralateral eyes, and healthy control eyes. We also compared eyes with PDR and contralateral eyes without PDR, patients with diabetes mellitus (DM) without DR, and healthy control eyes. The microvascular networks of the iris and retina were analyzed using optical coherence tomography angiography. The analysis included vessel area density (VAD) and vessel skeleton density (VSD) of iris and retina. RESULTS: In the RVO group, the VAD and VSD of iris in the affected eye were higher than those in contralateral and healthy control eyes, and the VAD and VSD of contralateral eyes were higher than those of healthy control eyes. The retinal blood flow of the RVO eyes was less than that of the contralateral and healthy control eyes, but there were no difference between the contralateral eyes and healthy control eyes. The VAD and VSD of iris in PDR were larger than nonproliferative diabetic retinopathy (NPDR) and the NPDR were larger than NDR. There were no differences between NDR and healthy control eyes. Also, there were no differences among the four groups with respect to retinal blood flow. CONCLUSIONS: Compared with the retina, iris blood circulation quantitative analysis data seem to be more sensitive to ischemia and may be used as a new predictor of ischemic disease, even if further research is needed to better understand the clinical value and importance of this analysis. TRIAL REGISTRATION: The trial is registered with the clinical trial registration number nct03631108 .