Visual acuity is correlated with ischemia and neurodegeneration in patients with early stages of diabetic retinopathy

Table 2 Number of patients with ischemia, neurodegeneration, and subclinical edema by BCVA and ETDRS severity groups

	Normal BCVA (n = 88)		Decreased BCVA (n = 44)		P value	ETDRS 20 (n = 56)		ETDRS 35 (n = 52)		ETDRS 43–53 (n = 24)		P value
	No	% (95% CI)	No	% (95% CI)	P value	No	% (95% CI)	No	% (95% CI)	No	% (95% CI)	P value
Ischemia
VD SRCP decrease	11	12.5 (5.6–19.4)	10	22.7 (10.3–35.1)	0.130	4	7.1 (0.4–13.9)	10	19.2 (8.5–29.9)	7	29.2 (11.0–47.4)	0.031
VD DRCP decrease	12	13.6 (6.5–20.8)	19	43.2 (28.5–57.8)	< 0.001	6	10.7 (2.6–18.8)	9	17.3 (7.0–27.6)	16	66.7 (47.8–85.5)	< 0.001
FAZ area increase	2	2.3 (0–5.4)	3	6.8 (0–14.3)	0.333	1	1.8 (0–5.3)	2	3.8 (0–9.1)	2	8.3(0–19.4)	0.333
VD decrease or FAZ area increase	17	19.3 (11.1–27.6)	21	47.7 (33.0–62.5)	0.001	8	14.3 (5.1–23.5)	13	25.0 (13.2–36.8)	17	70.8 (52.6–89.0)	< 0.001
Neurodegeneration
RNFL thinning	0	0	2	4.5 (0–10.7)	0.109	1	1.8 (0–5.3)	0	0	1	4.2 (0–12.2)	0.485
GCL-IPL thinning	0	0	4	9.1 (0.6–17.6)	0.011	1	1.8 (0–5.3)	2	3.8 (0–9.1)	1	4.2 (0–12.2)	0.672
RNFL or GCL-IPL thinning	0	0	5	11.4 (2.0–20.7)	0.004	2	3.6 (0–8.4)	2	3.8 (0–9.1)	1	4.2 (0–12.2)	1.000
Subclinical edema
INL thickening	3	3.4 (0–7.2)	2	4.5 (0–10.7)	1.000	2	3.6 (0–8.4)	0	0	3	12.5 (0–25.7)	0.031
OPL thickening	14	15.9 (8.3–23.6)	7	15.9 (5.1–26.7)	1.000	10	17.9 (7.8–27.9)	5	9.6 (1.6–17.6)	6	25 (7.7–42.3)	0.201
Total retinal thickening	0	0	0	0	NA	0	0	0	0	0	0	NA
INL or OPL or total retinal thickening	16	18.2 (10.1–26.2)	7	15.9 (5.1–26.7)	0.746	11	19.6 (9.2–30.0)	5	9.6 (1.6–17.6)	7	29.2 (11.0–47.4)	0.094

BCVA best-corrected visual acuity; ETDRS Early Treatment Diabetic Retinopathy Study; CI confidence interval; NA not applicable; VD vessel density; SRCP superficial retinal capillary plexus; DRCP deep retinal capillary plexus; FAZ foveal avascular zone; RNFL retinal nerve fiber layer; GCL-IPL ganglion cell layer plus inner plexiform layer; INL inner nuclear layer; OPL outer plexiform layer
Pathological changes in ischemia, neurodegeneration, and subclinical edema were accepted if the differences between the normal values, i.e., the mean value of healthy the control population and the DR group values were more than 1.96 standard deviation (SD) units. Thus, ischemia was diagnosed if the value of DR group was 1.96 SD less than the normal value of the control group. Neurodegeneration was diagnosed if the value of DR group was 1.96 SD less than that of the control group. Subclinical edema was diagnosed if the value of DR group was 1.96 SD more than normal value. P-values were based on the Chi-squared test result of the ratio of each group. Bold font indicates significance of P < 0.05

ISSN: 2326-0254