Retinal structure-function correlation in type 2 diabetes

The relationship between ON-OFF function and OCT structural and angiographic parameters in early diabetic retinal disease

PURPOSE

This study measured associations between ON and OFF functional indicators and structural optical coherence tomography (OCT) and OCT angiography (OCTA) markers in diabetic retinal disease.

METHODS

Fifty-four participants with type 1 or type 2 diabetes (mean age = 34.1 years; range 18-60) and 48 age-matched controls (mean age = 35.4 years, range 18-59) underwent visual psychophysical testing, OCT and OCTA retinal imaging. Psychophysical tasks measuring (A) contrast increment and decrement sensitivity and (B) response times to increment and decrement targets were assessed as surrogate measures of ON and OFF retinal ganglion cell function.

RESULTS

The group with diabetes had worse foveal contrast increment and decrement thresholds (p = 0.04) and were slower to search for increment and decrement targets relative to controls (p = 0.009). Individuals with diabetes had a less circular foveal avascular zone (FAZ) (p < 0.001) but did not differ from controls in foveal vessel density and FAZ area. Functional and structural outcome measures related to the peripheral retina were also comparable between those with and without diabetes. Functional responses to increments and decrements were not significantly correlated with FAZ circularity or vessel density in individuals with diabetes.

CONCLUSIONS

Diabetic retinal disease results in impaired performance on measures of inferred ON and OFF pathway function in addition to vascular deficits measurable with OCTA. Future longitudinal studies may determine the temporal relationship between these deficits, and whether they predict future diabetic retinopathy.

Retinal Neurovascular Impairment in Full-Course Diabetic Retinopathy: The Guangdong Diabetic Retinopathy Multiple-Omics Study

Purpose

The purpose of this study was to explore the succession of the central and peripheral neurovascular and microstructural impairments in patients with full-course diabetic retinopathy (DR), consisting of preclinical DR, nonproliferative DR (NPDR), and proliferative DR (PDR).

Methods

Our analysis included 81 participants (including 23 healthy controls, 23 with preclinical DR [diabetes without retinopathy], 13 with NPDR, and 22 with PDR) from the Guangdong Diabetic Retinopathy Multiple Omics Study. Retinal structure and function were evaluated and quantified using ultra-widefield swept-source optical coherence tomography angiography (UWF-SS-OCTA), electroretinography (ERG), and adaptive optics scanning laser ophthalmoscopy (AOSLO). Correlation analysis was conducted to explore the relationship between structural parameters and functional parameters.

Results

In the preclinical DR group, decreased amplitude in the DR assessment protocol were observed (P = 0.003), with no changes in structure and photoreceptor cells (all P > 0.05). In the NPDR group, photoreceptor cells were impaired (all P < 0.05) with delayed implicit time in the International Society for Clinical Electrophysiology of Vision (ISCEV) Photopic flicker protocol, increased macular and inner nuclear layer thickness, and decreased vessel density and perfusion area of the deep capillary plexus (all P < 0.05). In the PDR group, delayed implicit time and decreased amplitude in the ISCEV Photopic flicker and photopic negative response (PhNR) protocol, and neurovascular impairments were observed (all P < 0.05). Correlation analysis demonstrated a significant correlation between functional parameters and various structural indicators (all P < 0.05).

Conclusions

The cone pathway function began to decline in preclinical DR and distinct photoreceptor cell disorders were observed in NPDR. Notably, instruments with a wider field of view or more detailed microscopic techniques will provide enhanced neurovascular imaging, offering fresh insights into full-course DR.

Contrast Sensitivity Better Reflects Wide-Field Swept-Source Optical Coherence Tomography Angiography Vascular Metrics Among Healthy Eyes Compared to Visual Acuity

BACKGROUND AND OBJECTIVE

To evaluate the association between widefield swept-source optical coherence tomography angiography (WF SS-OCTA) and visual function in healthy eyes.

PATIENTS AND METHODS

Fifty-seven eyes of 45 patients were evaluated with visual acuity (VA), contrast sensitivity (CS), and WF SS-OCTA (3 × 3, 6 × 6, and 12 × 12 mm images) on the same day. Mixed-effects multivariable regression analyses were performed.

RESULTS

Contrast sensitivity metrics, including CS between 6 to 18 cycles per degree (cpd) and area under the logarithm CS function, were significantly associated with vessel density (VD) and vessel skeletonized density (VSD), whereas VA was not. The largest effect size was between CS at 18 cpd and VD (β = 0.41, P = 0.007) and VSD (β = 0.42, P = 0.006) on 12 × 12 mm images.

CONCLUSIONS

Reduced VSD and VD on WF SSOCTA was significantly associated with decreased CS, whereas VA was not. These results suggest CS could serve as a screening tool for early stage retinal and neurologic disorders. [Ophthalmic Surg Lasers Imaging Retina 2024;55:494-502.].

Associations of quantitative contrast sensitivity with wide-field swept-source optical coherence tomography angiography in retinal vein occlusion

PURPOSE

To investigate associations between contrast sensitivity (CS) and vascular metrics on wide-field swept-source optical coherence tomography angiography (WF-SS-OCTA) in patients with retinal vein occlusion (RVO).

METHODS

This prospectively recruited, cross-sectional observational study included RVO patients who underwent quantitative CS function (qCSF) testing and WF-SS-OCTA using 3 × 3, 6 × 6, and 12 × 12 mm angiograms on the same day. The study measured several qCSF outcomes and WF-SS-OCTA vascular metrics, including vessel density (VD), vessel skeletonized density (VSD), and foveal avascular zone (FAZ). The data were analyzed using multivariable regression analysis controlling for age and central subfield thickness (CST).

RESULTS

A total of 43 RVO eyes of 43 patients and 30 fellow eyes were included. In RVO eyes, multiple vascular metrics were associated with CS outcomes but not visual acuity (VA). On 12 × 12 images, CS thresholds at 1 cpd, 1.5 cpd, and 3 cpd were significantly associated with VD and VSD, but VA was not. When comparing standardized regression coefficients, we found that vascular metrics had a larger effect size on CS than on VA. For instance, the standardized beta coefficient for FAZ area and CS at 6 cpd (β* = - 0.46, p = 0.007) was larger than logMAR VA (β* = 0.40, p = 0.011).

CONCLUSION

Microvascular changes on WF-SS-OCTA in RVO had a larger effect size on CS than VA. This suggests CS may better reflect the microvascular changes of RVO compared to VA. qCSF-measured CS might be a valuable adjunct functional metric in evaluating RVO patients.

Contrast Sensitivity Deficits and Its Structural Correlates in Fuchs Uveitis Syndrome

Purpose

To investigate the deficits in contrast sensitivity in patients with Fuchs uveitis syndrome (FUS) and to explore the potential relationship between contrast sensitivity and ocular structure.

Methods

In this prospective study, 25 patients with FUS and 30 healthy volunteers were recruited. Eyes were divided into three groups: FUS-affected eyes (AE), fellow eyes (FE), and healthy eyes. The contrast sensitivity function (CSF) of all participants was evaluated using the quick CSF (qCSF) method. Fundus photographs were collected for the analysis of refractive media, and vascular density (VD) was assessed using optical coherence tomography angiography (OCTA). Data were analyzed and compared using the generalized estimating equation (GEE).

Results

The CSF of AE was significantly lower than that of FE and controls, while no significant difference was observed between FE and controls. Contrast sensitivity was negatively correlated with the grade of haze. No significant correlation was found between visual function and VDs in FUS eyes.

Conclusions

We found that the CSF of FUS-affected eyes was significantly reduced, and the visual impairment was predominantly caused by the refractive media turbidity.