Effects of Prolonged Type 2 Diabetes on the Inner Retinal Layer and Macular Microvasculature: An Optical Coherence Tomography Angiography Study

Lim

Kim

et al. 2021

Sci Rep

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To identify the effects of prolonged type 2 diabetes (T2DM) on changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in patients without clinical diabetic retinopathy. Subjects were divided into two groups: controls and patients with T2DM (DM group). After the initial visits, the pRNFL thicknesses were measured three more times at 1-year intervals. Subgroup analyses were performed in patients with T2DM duration ≥ 10 years. The mean pRNFL thickness at each visit was 95.8 ± 8.1, 95.4 ± 8.3, 94.9 ± 8.1, and 94.5 ± 8.3 μm in the control group (P = 0.138) (n = 55); and 93.4 ± 9.1, 92.1 ± 9.3, 90.9 ± 9.3, and 89.5 ± 9.2 μm in the DM group (P < 0.001) (n = 85). The estimated rate of reduction in mean pRNFL thickness was − 0.45 μm/year in the control group and − 1.34 μm/year in the DM group, respectively. In the DM group, the BCVA and HbA1c (both P = 0.001) were significant factors associated with pRNFL reduction. In patients with T2DM duration ≥ 10 years, the estimated pRNFL reduction rate was − 1.61 μm/year, and hypertension was a significant factor affecting the pRNFL reduction (P = 0.046). We confirmed rapid pRNFL reduction over time in T2DM, and the reduction rate was higher in patients with T2DM ≥ 10 years. Additionally, BCVA and HbA1c levels were significantly associated with the change in pRNFL thickness in T2DM patients.

Section: Discussionmentioning

confidence: 95%

Effects of prolonged type 2 diabetes on changes in peripapillary retinal nerve fiber layer thickness in diabetic eyes without clinical diabetic retinopathy

Lim

Kim

et al. 2021

Sci Rep

Self Cite

“…These results were similar to our previous study that patients with prolonged T2DM exhibited thinner macular GC-IPL and more severe impairment of macular microvasculature. 21 Neuronal death and glial dysfunction by diabetic retinal neurodegeneration can cause a breakdown of the blood-retinal barrier, vasoregression, and impairment of neurovascular coupling, which may result in early microvascular impairment. 16 As the damages caused by such diabetic retinal neurodegeneration accumulated, the patients with prolonged T2DM would show more severely damaged microvasculature similar to pRNFL thinning.…”

Section: Discussionmentioning

confidence: 99%

Peripapillary Retinal Nerve Fiber Layer and Microvasculature in Prolonged Type 2 Diabetes Patients Without Clinical Diabetic Retinopathy

Invest. Ophthalmol. Vis. Sci.

Ryu

et al. 2021

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Purpose The purpose of this study to identify the effects of prolonged type 2 diabetes (T2DM) on the peripapillary retinal nerve fiber layer (pRNFL) and peripapillary microvasculature in patients with prolonged T2DM without clinical diabetic retinopathy (DR). Methods Subjects were divided into 3 groups: controls (control group; 153 eyes), patients with T2DM < 10 years (DM group 1; 136 eyes), and patients with T2DM ≥ 10 years (DM group 2; 74 eyes). The pRNFL thickness and peripapillary superficial vessel density (VD) were compared. Linear regression analyses were performed to identify factors associated with peripapillary VD in patients with T2DM. Results The mean pRNFL thicknesses of the control group, DM group 1, and DM group 2 were 96.0 ± 7.9, 94.5 ± 0.9, and 92.2 ± 8.2 µm, respectively ( P < 0.001). The VDs were 18.24 ± 0.62, 17.60 ± 1.47, and 17.15 ± 1.38 mm −1 in the control group, DM group 1, and DM group 2, respectively ( P < 0.001). In multivariate linear regression analyses, visual acuity (B = −2.460, P = 0.001), axial length (B = −0.169, P = 0.008), T2DM duration (B = −0.056, P < 0.001), and pRNFL (B = 0.024, P = 0.001) were significant factors affecting the peripapillary VD in patients with T2DM. Conclusions Patients with T2DM without clinical DR showed thinner pRNFL and lower peripapillary VD and perfusion density (PD) compared with normal controls, and such damage was more severe in patients with T2DM ≥ 10 years. Additionally, peripapillary VD was significantly associated with best-corrected visual acuity (BCVA), axial length, T2DM duration, and pRNFL thickness in patients with T2DM.

“… 4 An autoregulatory response of the neurovascular unit to complex circulatory and neural cues is essential to regulate blood flow through the inner retina owing to the lack of autonomic innervation of the intraretinal vasculature, so disruption of the neurovascular unit by DRN would affect the impaired macular microcirculation. 3 , 4 , 7 , 24 Therefore, even in the absence of signs related to DR, such as microaneurysm or retinal hemorrhage, patients with T2DM would have impaired macular microcirculation and microvasculature.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, patients showing DR changes, such as retinal hemorrhage, hard exudates, and cotton wool spots, require careful observation for various DR-related complications. Meanwhile, anatomical and functional impairments of the retina have been reported recently in diabetic patients without clinical DR. Diabetic retinal neurodegeneration (DRN), which causes accelerated inner retinal reduction over time, is a representative type of retinal damage preceding DR. 2 – 6 Additionally, as detailed observation of microvasculature at high resolution has become possible using optical coherence tomography angiography (OCTA), impairments of peripapillary and macular microvasculature have been reported in diabetic patients without DR. 7 , 8 …”

mentioning

confidence: 99%

Impacts of Systemic Hypertension on the Macular Microvasculature in Diabetic Patients Without Clinical Diabetic Retinopathy

Koo

Invest. Ophthalmol. Vis. Sci.

et al. 2021

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Purpose To identify the impact of hypertension (HTN) on macular microvasculature in type 2 diabetes (T2DM) patients without clinical diabetic retinopathy. Methods In this retrospective cross-sectional study, subjects were divided into three groups: controls (control group), patients with T2DM (DM group), and patients with both T2DM and HTN (DM + HTN group). The vessel length density (VD) was compared among the groups. Linear regression analyses were performed to identify factors associated with VD. Results The VD in the control, DM, and DM + HTN groups was 20.43 ± 1.16, 19.50 ± 1.45, and 18.19 ± 2.06 mm −1 , respectively ( P < 0.001). The best-corrected visual acuity (B = −9.30; P = 0.002), duration of T2DM (B = −0.04; P = 0.020), HTN (B = −0.51; P = 0.016), signal strength (B = 1.12; P < 0.001), and ganglion cell–inner plexiform layer thickness (B = 0.06; P < 0.001) were significant factors affecting VD in patients with T2DM. Additionally, the hemoglobin A1c (HbA1c) (B = −0.49; P = 0.016) was significantly associated with VD in patients with both T2DM and HTN. Conclusions Patients with T2DM had impaired macular microvasculature, and patients with T2DM with HTN exhibited greater impairment of the microvasculature than did patients with T2DM only. Additionally, physicians should be aware that the macular microvasculature would be more vulnerable to hyperglycemic damage under ischemic conditions by HTN.