A recent study published in BMC Ophthalmology identified potential systemic factors that influence the retinal microvascular network in participants with and without diabetes.
Give me some background first.
Diabetes is a chronic condition that impacted an estimated 8.4 million Americans in 2021; it’s also the eighth leading cause of death in the United States.
Connection between diabetes and vision: Diabetes can induce damage to the eyes over time and—in some instances—may cause vision loss or blindness.
Ocular conditions that may result from diabetes include:
- Diabetic retinopathy (DR)
- Cataracts
- Glaucoma
Now, talk about the study.
Investigators utilized data from a cross-sectional study called the Kailuan Eye Study.
In this study, researchers administered optical coherence tomography angiography (OCTA) and a comprehensive systemic examination for participants.
They then assessed the following metrics:
- Perfusion density (PD)
- Vascular density (VD)
- Foveal avascular zone (FAZ)
- Parameters of the superficial capillary plexus (SCP)
- Within the macula
Give me a rundown on the Kailuan Eye Study.
The Kailuan Eye Study was based on the community-based cohort Kailuan Study.
Between 2006 to 2007 the cohort consisted of:
- 101,510 participants from the Kailuan community
- Aged 18 to 98
Of these individuals, 14,440 were randomly selected to participate in the Kailuan Eye Study. These participants underwent the following at each interval:
- Standardized interviews
- Laboratory assessments
Then: From March to June 2017, 897 participants were randomly recruited and underwent OCTA examination.
So who was included in this study?
A total of 860 participants comprised of:
- 449 diabetic participants
- 411 non-diabetic participants
- Aged 27 to 83
- Mean age = 62.75 ± 6.52 years
- 188 (21.9%) female
Note: There were no significant age or sex differences between the diabetic and non-diabetic groups.
Findings?
Participants with diabetes had diminished PD and VD in the entire macular and parafoveal regions compared to those without.
Reduced PD in the whole macular region was associated with:
- Higher fasting plasma glucose (FPG; mmol/L) concentration
- Beta = -0.19, 95% CI = -0.42 to -0.36, P < 0.001
- Longer axial length (AL; mm)
- Beta = -0.13, 95% CI = -0.48 to -0.25, P = 0.002
- Elevated heart rate
- Beta = -0.10, 95%CI = -0.14 to -0.19, P = 0.014
- After adjusting for younger age (Beta = -0.18, 95%CI = -0.24 to -0.35, P < 0.001), consistent with VD of the whole macular region
Tell me more.
Higher FPG level was significantly associated with:
- Lower SCP density of both PD and VD in the macular and parafoveal region
- P < 0.05 for all
- Increased systolic blood pressure and low-density lipoprotein cholesterol concentration
- P < 0.01 for all
Limitations?
Selection bias may have occurred since the original cohort study was not population-based.
Additionally, since the study was cross-sectional, the researchers could not identify correlations from their findings as casual relationships.
Lastly, they were unaware of the duration of diabetes.
Which means: The effect on DR severity and retinal microvascular system was not analyzed.
Expert opinion?
The authors noted that their findings imply that OCTA may be used to monitor early subclinical changes in retinal microvasculature.
They also stated, “Regular OCTA screening is beneficial for the diagnosis, classification and intervention of chronic systemic disease.”
Take home.
The study found that high prevalence of diabetes and elevated FPG levels may be correlated with reduced retinal VD and PD.
Further, hypertension and hyperlipidemia may be important risk factors for the development of atherosclerotic cardiovascular disease and diabetes; however, they may have no significant effect on retinal microvascular abnormalities.