Association Between Corneal Changes and Retinal Oximetry in Diabetes Mellitus

Figures & data

Table 1 Baseline Data and Oxygen Saturation Values of Retinal Vessels in Diabetes Mellitus Patients and Healthy Subjects

	DM Patients	Healthy Subjects	p value
Number	30	30
Age (years)	69.6 ± 11.5	67.5 ± 10.3	0.539
IOP (mmhg)	15.2 ± 4.3	15.7 ± 3	0.412
Systolic BP (mmhg)	154.5 ± 20.5	130.7 ± 13.3	< 0.001
Diastolic BP (mmhg)	86.7 ± 11.4	77.3 ± 10.2	0.001
Mean arterial BP (mmhg)	120.6 ± 14.5	104 ± 10.5	< 0.001
Arterial SO2 (%)	100.7 ± 6.5	97.4 ± 4.9	0.048
Venous SO2 (%)	69.8 ± 9.5	59 ± 6.7	< 0.001
Arteriovenous SO2 difference (%)	30.9 ± 7.5	38.5 ± 5.5	< 0.001

Abbreviations: DM, diabetes mellitus; IOP, intraocular pressure; BP, blood pressure; SO₂, oxygen saturation.

Table 2 Results of Pentacam Measurements in Diabetes Mellitus Patients and Healthy Subjects

Number		DM Patients	Healthy Subjects	p value
		30	30
CCT (µm)		553 ± 100.6	557.2 ± 36.2	0.785
Spatially resolved pachymetry (in µm)
PAC TCT		551 ± 31.9	552.1 ± 33.7	0.994
PAC 2 mm		561.4 ± 34.4	559.2 ± 33.7	0.846
PAC 4 mm		588.1 ± 28.4	583.7 ± 34.6	0.695
PAC 6 mm		634.4 ± 29.8	621.6 ± 36.7	0.215
PAC 8 mm		699.6 ± 37.9	672.9 ± 42.6	0.031
PAC 10 mm		788.8 ± 47.6	738.5 ± 58.1	0.003
PACDiff 2 mm		11.8 ± 7.3	8.5 ± 2.1	0.001
PACDiff 4 mm		40.5 ± 8.8	33 ± 5.2	< 0.001
PACDiff 6 mm		86.9 ± 16.4	70.9 ± 10.3	< 0.001
PACDiff 8 mm		152 ± 27.2	122.3 ± 18	< 0.001
PACDiff 10 mm		239.2 ± 42	189.7 ± 39.4	< 0.001
Corneal optical density (in GSU)
Anterior layer (total)		29.8 ± 9.5	36.5 ± 7.7	0.018
Central layer (total)		19.9 ± 6	24.8 ± 5.6	0.008
Posterior layer (total)		15.6 ± 4.7	20.5 ± 4.1	< 0.001
All layers	0–2 mm	16.8 ± 5.6	19 ± 1.9	0.076
	2–6 mm	16.4 ± 4.9	19.3 ± 2.8	0.04
	6–10 mm	25.5 ± 8.9	34.1 ± 9.3	0.003
	10–12 mm	31.4 ± 10.4	40.9 ± 12.2	0.003
	total	21.8 ± 6.6	27.3 ± 5.3	0.004

Abbreviations: DM, diabetes mellitus; CCT, central corneal thickness; TCT, thinnest corneal thickness; PAC, mean pachymetry values of concentric rings around TCT, circle diameter indicated in mm; PAC_Diff, difference of pachymetry values between TCT and the concerning concentric circle.

Figure 1 Association between oxygen saturation of retinal arterioles (in %), retinal arteriovenous saturation difference (in %), and difference between central thinnest corneal thickness and peripheral thickness of the cornea measured at a concentric ring with a diameter of 4 mm (PAC Diff 4 mm, in µm) in diabetes mellitus.

Figure 2 Correlation between retinal arterial oxygen saturation (in %) and peripheral corneal optical density (of all layers at 10 to 12 mm diameter, in µm) in diabetes mellitus patients.