Corneal endothelium and central corneal thickness changes in type 2 diabetes mellitus

Figures & data

Table 1 Demographics of control and diabetic patients (eyes)

Demographic data	Control group	DM patients (eyes)
Patients (eyes) (n)/percent	45/44.1%	57/55.9%
Mean age ± SD/range (years)	50.80±8.39/40–76	57.08±8.37/42–80
Sex (males/females) (n)	22/23	27/30

Abbreviations: DM, diabetes mellitus; SD, standard deviation.

Table 2 Classification of groups of diabetic eyes

Clinical data	DR			DM duration (years)		HbA1c
	No DR	NPDR	PDR	≤10	>10	≤7.5%	>7.5%
Eyes (n)	36	14	7	26	31	24	33

Abbreviations: DM, diabetes mellitus; DR, diabetic retinopathy; HbA_1c, glycated hemoglobin; NPDR, nonproliferative DR; PDR, proliferative DR.

Figure 1 Corneal endothelium picture taken by EM-3000 Specular Microscope (CBD/Tomey, Phoenix, AZ, USA) for non-DM female (46 years old).

Abbreviation: DM, diabetes mellitus.

Figure 2 Corneal endothelium picture taken by EM-3000 Specular Microscope (CBD/Tomey, Phoenix, AZ, USA) for DM female (46 years old) with PDR (DM duration of 20 years and HbA_1c =9.2%).

Abbreviations: DM, diabetes mellitus; HbA_1c, glycated hemoglobin; PDR, proliferative diabetic retinopathy.

Figure 3 Corneal endothelium picture taken by EM-3000 Specular Microscope (CBD/Tomey, Phoenix, AZ, USA) for non-DM male (58 years old).

Abbreviation: DM, diabetes mellitus.

Figure 4 Corneal endothelium picture taken by EM-3000 Specular Microscope (CBD/Tomey, Phoenix, AZ, USA) for DM male (56 years old) without DR (DM duration of 8 years and HbA_1c =9.5%).

Abbreviations: DM, diabetes mellitus; DR, diabetic retinopathy; HbA_1c, glycated hemoglobin.

Table 3 A comparison of the mean values of CCT, ECD, CV, and hexagonality between control and diabetic eyes (mean ± SD)

Group	CCT (µm)	ECD (cell/mm^2)	CV	Hexagonality (%)
Control	539.42±29.22	2,629.68±293.45	0.37±0.08	34.24±8.73
DM	545.61±30.39	2,491.98±261.08	0.41±0.07	33.24±10.25
P-value	0.301	0.014	0.008	0.603

Abbreviations: CCT, central corneal thickness; CV, coefficient of variation of cell area; DM, diabetes mellitus; ECD, endothelial cell density; SD, standard deviation.

Table 4 A comparison of the mean values of CCT, ECD, CV, and hexagonality between the diabetic groups, according to duration of DM (mean ± SD)

DM duration (years)	CCT (µm)	ECD (cell/mm^2)	CV	Hexagonality (%)
≤10	549.11±30.57	2,509.38±303.49	0.41±0.09	35.61±9.87
>10	542.67±30.43	2,477.38±223.61	0.42±0.04	31.26±10.29
P-value	0.431	0.658	0.927	0.111

Abbreviations: CCT, central corneal thickness; CV, coefficient of variation of cell area; ECD, endothelial cell density; HbA_1c, glycated hemoglobin; SD, standard deviation.

Table 5 A comparison of the mean values of CCT, ECD, CV, and hexagonality between the diabetic groups, according to HbA_1c% (mean ± SD)

HbA1c %	CCT (µm)	ECD (cell/mm^2)	CV	Hexagonality (%)
≤7.5	544.33±28.89	2,537.62±311.86	0.39±0.05	35.58±10.09
>7.5	546.54±31.84	2,458.78±216.06	0.43±0.07	31.54±10.17
P-value	0.789	0.293	0.017	0.144

Abbreviations: CCT, central corneal thickness; CV, coefficient of variation of cell area; ECD, endothelial cell density; HbA_1c, glycated hemoglobin; SD, standard deviation.

Table 6 A comparison of the mean values of CCT, ECD, CV, and hexagonality between the diabetic groups, according to the status of DR (mean ± SD)

DR status	CCT (µm)	ECD (cell/mm^2)	CV	Hexagonality (%)
No DR	550.14±31.23	2,478.61±286.71	0.40±0.07	34.25±9.91
NPDR	537.50±27.73	2,497.98±240.52	0.44±0.05	30.43±10.08
PDR	538.57±30.47	2,549.86±162.02	0.42±0.05	33.71±12.73
P-value	0.344	0.806	0.284	0.500

Abbreviations: CCT, central corneal thickness; CV, coefficient of variation of cell area; DR, diabetic retinopathy; ECD, endothelial cell density; NPDR, nonproliferative DR; PDR, proliferative DR; SD, standard deviation.

Table 7 Correlation between corneal changes and DM duration, HbA_1c%, and DR status

Clinical data	CCT (µm)	ECD (cell/mm^2)	CV	Hexagonality (%)
DM duration, years
R value	−0.163	−0.069	0.051	−0.134
P-value	0.226	0.610	0.702	0.320
HbA1c %
R value	0.156	−0.218	0.125	−0.160
P-value	0.245	0.103	0.351	0.234
DR status
R value	−0.175	0.085	0.158	−0.081
P-value	0.192	0.527	0.240	0.554

Abbreviations: CCT, central corneal thickness; CV, coefficient of variation of cell area; DM, diabetes mellitus; DR, diabetic retinopathy; ECD, endothelial cell density; HbA_1c, glycated hemoglobin; SD, standard deviation.