Retinal oximetry and microvascular assessment after hypertensive pregnancy complications.

PURPOSE: Women with hypertensive disorders of pregnancy (HDP) are at increased risk of developing premature cardiovascular disease (CVD). The mechanisms behind this are not fully understood, but microvascular alterations have been documented in retinal arterioles and venules. The aim of this study was to use non-invasive retinal imaging to investigate the structural and functional properties of arterioles, venules and capillaries in this patient group. METHODS: We examined 27 women with previous HDP and 23 controls at 3 years postpartum. The retinal microvasculature was assessed by vessel calibre measurements, retinal oximetry and optical coherence tomography angiography. Differences were analysed using non-parametric tests and multiple regression analyses, adjusted for age and body mass index. RESULTS: Median arteriolar oxygen saturation (SaO2 ; 94.2% vs. 93.0%), venular oxygen saturation (SvO2 ; 60.1% vs. 62.4%) and arteriovenous saturation difference (AV-difference; 32.8% vs. 32.3%) were similar across groups. Capillary vessel density (VD; 46.2% vs. 46.3%), skeletonised VD (VSD; 21.3 vs. 21.1 mm/mm2 ) and vessel diameter index (21.65 vs. 21.86) were also comparable. In the HDP group, mean arterial pressure (MAP) was positively correlated with AV-difference (R2 = 0.209) and negatively correlated with arteriolar diameter (CRAE; r2 = 0.382). CONCLUSIONS: Structural microvascular alterations appear not to be key biomarkers for CVD risk after HDP as early as 3 years postpartum in otherwise healthy women. Further studies are needed to evaluate whether such changes occur later in life. MAP was associated with AV-difference only in the HDP group, suggesting specific mechanisms affecting functional microvascular properties in these women.

Exploring Retinal Blood Vessel Diameters as Biomarkers in Multiple Sclerosis.

We aimed to determine whether retinal vessel diameters and retinal oxygen saturation in newly diagnosed patients with multiple sclerosis (pwMS) are different from those of a healthy population. Retinal blood vessel diameters were measured using imaging with a spectrophotometric non-invasive retinal oximeter. Twenty-three newly diagnosed untreated relapsing-remitting MS (RRMS) patients (mean age: 32.2 ± 7.5 years, age range = 18-50 years, 56.5% female) were measured and compared to 23 age- and sex-matched healthy controls (HCs) (mean age: 34.8 ± 8.1 years). Patients with Optic Neuritis were excluded. Retinal venular diameter (143.8 µm versus 157.8 µm: mean; p = 0.0013) and retinal arteriolar diameter (112.6 µm versus 120.6 µm: mean; p = 0.0089) were smaller in pwMS when compared with HCs, respectively. There was no significant difference in the oxygen saturation in retinal venules and arterioles in pwMS (mean: 60.0% and 93.7%; p = 0.5980) compared to HCs (mean: 59.3% and 91.5%; p = 0.8934), respectively. There was a significant difference in the median low contrast visual acuity (2.5% contrast) between the pwMS and the HC groups (p = 0.0143) Retinal arteriolar and venular diameter may have potential as objective biomarkers for MS.

Retinal venular oxygen saturation is associated with non-proliferative diabetic retinopathy in young patients with type 1 diabetes.

PURPOSE: To determine the contribution of retinal vessel density (VD), central retinal vessel diameter and retinal oxygen (O2 ) saturation independently of other known risk factors in the development of non-proliferative diabetic retinopathy (NPDR). METHODS: Macular optical coherence tomography angiography (OCTA), central retinal artery/vein equivalent diameter (CRAE/CRVE) measurements and retinal oximetry were performed in a cross-sectional study of 166 eyes from 166 individuals with type 1 diabetes (T1D) aged 14-30 years. Multiple logistic regression analysis was used to investigate whether O2 saturation, retinal vessel diameters and vessel density in the deep capillary plexus (VD-DCP) were associated with NPDR, when adjusting for known risk factors. The individuals were allocated to one group without and one group with NPDR. RESULTS: Multiple logistic regression analysis showed that age (OR = 1.25, 95% CI: 1.04-1.49) and AV-difference in O2 saturation (OR = 0.85, 95% CI 0.77-0.93) were significantly associated with NPDR. CONCLUSION: Our findings suggest that age and lower AV-O2 saturation difference contribute to explaining the grade of NPDR independently of other well-known risk factors. Reduced delivery of O2 to the retinal tissue is associated with the development of NPDR in young patients with T1D and should be given appropriate weight in the risk stratification at early stages of the disease.

Associations between Macular OCT Angiography and Nonproliferative Diabetic Retinopathy in Young Patients with Type 1 Diabetes Mellitus.

METHODS: OCTA of both eyes was performed in a cross-sectional study of 14 to 30-year-old individuals with at least 10-year duration of T1D and controls recruited from the Norwegian Atherosclerosis and Childhood Diabetes (ACD) study. Vessel density (VD) and foveal avascular zone (FAZ) area in the superficial and deep capillary plexus (SCP and DCP), total retinal volume (TRV), and central macular thickness (CMT) were calculated using automated software. Univariate and multivariate ordered logistic regression (OLR) models were used accordingly. RESULTS: We included 168 control eyes and 315 T1D eyes. Lower VD in DCP (OR 0.65, 95% CI 0.51-0.83), longer diabetes duration (OR 1.51, 95% CI 1.22-1.87), and higher waist circumference (OR 1.08, 95% CI 1.02-1.14) were significantly associated with progression of NPDR. VD in SCP and DCP were significantly lower in T1D patients without diabetic retinopathy than in controls. CONCLUSIONS: Sparser VD in DCP is significantly associated with severity of NPDR, supporting that OCTA might detect the earliest signs of NPDR before it is visible by ophthalmoscopy.

Venular oxygen saturation is increased in young patients with type 1 diabetes and mild nonproliferative diabetic retinopathy.

PURPOSE: To clarify how early in the development of diabetic retinopathy (DR) can oxygen (O2 ) saturation changes be detected. METHODS: Retinal oximetry was performed in a cross-sectional study, involving 14- to 30-year-old individuals: 185 with type 1 diabetes (T1D) and 94 controls. The subjects were divided into four groups according to the grade of DR. One-way ANOVA and post hoc tests were used to test for differences in the mean O2 saturations between the groups. RESULTS: Fifty-eight (31 %) of the T1D patients had nonproliferative DR. There was no significant difference in O2 saturations between controls and T1D patients with no DR. Arteriolar and venular O2 saturations in T1D patients were significantly higher in moderate/severe DR than in no DR (p = 0.009 and p > 0.001), while venular O2 saturation was significantly higher in mild DR than in no DR (p = 0.013). CONCLUSION: Increase in venular O2 saturation could not be detected before mild retinopathy had developed, and the retinal O2 saturation increase was measurable on the venular side first. Our results suggest that the increase in O2 saturation is likely a consequence of DR.

Cost-effectiveness of the triple procedure - phacovitrectomy with posterior capsulotomy compared to phacovitrectomy and sequential procedures.

PURPOSE: To evaluate the cost-effectiveness of the triple procedure (phacovitrectomy + posterior capsulotomy, PhacoPPVc) compared to the double- (phacovitrectomy, PhacoPPV) or single sequential procedures. METHODS: Prospective study on 31 eyes from 31 patients (mean age: 72.1 ± 9.1 years; 55% females) was performed with a preoperative decision to undergo only pars plana vitrectomy (PPV) (26%) or PhacoPPV (74%) and/or posterior capsulotomy based upon presence or absence of lens opacification or pseudophakia. Time during and between surgeries, surgical procedure codes, medical and transport costs, outcome and likelihood of complications after surgery were all included in the analysis. Societal perspectives and visual acuity were considered as measures of quality of adjusted life years (QALYs). RESULTS: About 23 eyes underwent triple procedure and eight eyes underwent vitrectomy only (mean surgery times: 35.9 and 24.0 min, respectively). Posterior capsulotomy took on average 30 s, while preparation and cataract procedure took 13.0 min. The patients travelled on average 80km (average cost: $280.12) to the surgery unit. The average reimbursement fee for the day procedures ranged between $174.17 (YAG capsulotomy; Diagnosis Related Group (DRG): 0.034), $1045.48 (Phaco + intraocular lens (IOL); DRG: 0.204) and $1701.32 (PPV; DRG: 0.332). The combined procedures excluded lens and laser reimbursements, while the calculated reimbursements for the double/triple procedures were $2713.08/$2901.45, respectively, without significant loss of QALYs. PhacoPPVc was found to be unequivocally cost-effective, while PhacoPPV remained cost saving compared to sequential procedures. CONCLUSION: This study confirms that the triple procedure has benefits to the patients, health institution and surgeon. For patients, it saves them travel and healing time; for health institution, it justifies the calculated higher costs and need for higher reimbursement for the double/triple procedures, which are cost saving.

Relationship between retinal vessel diameters and retinopathy in the Inter99 Eye Study.

PURPOSE: To examine the association between retinal vessel diameters and retinopathy in participants with and without type 2 diabetes in a Danish population-based cohort. METHODS: The study included 878 persons aged 30 to 60 years from the Inter99 Eye Study. Retinopathy was defined as a presence of one or more retinal hemorrhages or one or more microaneurysms. Vessel diameters were expressed as central retinal artery equivalent diameter (CRAE) and central retinal vein equivalent diameter (CRVE). Multiple linear regression analyses were performed. RESULTS: Among participants with diabetes, CRAE was 6.3 µm (CI 95%: 1.0 to 11.6, p = 0.020) wider and CRVE was 7.9 µm (CI 95%: 0.7 to 15.2, p = 0.030) wider in those with retinopathy compared to those without retinopathy, after adjusting for age, gender, HbA1c, blood pressure, smoking, serum total and HDL cholesterol. In all participants, CRAE increased with presence of retinopathy (p = 0.005) and with smoking (p = 0.001), and CRAE decreased with hypertension (p < 0.001), high HDL cholesterol (p = 0.016) and age (p < 0.001). Central retinal vein equivalent diameter increased with presence of retinopathy (p = 0.022) and with smoking (p < 0.001), and decreased with higher HDL cholesterol (p < 0.001) and age (p = 0.015). Female gender was associated with wider CRVE (p = 0.029). CONCLUSIONS: Wider retinal vessel diameters were associated with the presence of retinopathy in participants with diabetes, but not in participants without diabetes. The associations between retinal vessel diameters and known retinopathy risk factors were confirmed. These results suggest that information obtained by non-invasive imaging of the interior of the eye can contribute to a better understanding of systemic disease processes.

Retinal Vessel Diameters and Their Relationship with Cardiovascular Risk and All-Cause Mortality in the Inter99 Eye Study: A 15-Year Follow-Up.

Purpose. To describe associations between retinal vessel diameters and cardiovascular risk markers and mortality. Methods. The present study included 908 persons aged 30 to 60 years. Vessel diameters were expressed as central retinal venular equivalent (CRVE) and central retinal arteriolar equivalent (CRAE). Multiple linear regression analyses and Cox regression models were used. Results. Multiple linear regression analyses showed that narrower CRAE was associated with higher systolic blood pressure, age, and higher HDL cholesterol, whereas wider CRAE and CRVE were associated with smoking. Narrower CRVE was associated with higher HDL cholesterol. In an age-adjusted model, associations between wider CRVE and risk of ischemic heart disease were found (P < 0.001). Wider CRVE was associated with all-cause mortality (HR = 2.02, P = 0.033) in a model adjusted for age, gender, and blood pressure. However, the association was not statistically significant after additional adjustment for smoking. Conclusions. The associations between retinal vessel diameters and known cardiovascular risk factors were confirmed. All-cause mortality was not associated with retinal vessel diameters when adjusting for relevant confounders.