Characteristics of Corneal Subbasal Nerves in Different Age Groups: An in vivo Confocal Microscopic Analysis

Figures & data

Table 1 Demographic Data of 80 Healthy Subjects, Aged Between 20–60 Years

	Age (Years)				Total
	20–30	> 30–40	> 40–50	> 50–60
Mean age (± SD)	24.85 ± 2.45	35.25 ± 2.76	44.05 ± 2.78	54.90 ± 2.77
Number	20	20	20	20	80
Male (mean age)	10 (24.3)	10 (34.5)	10 (43.5)	10 (54.5)	40
Female (mean age)	10 (25.4)	10 (36.0)	10 (44.6)	10 (55.3)	40
Laterality
Right eye	10	10	10	10	40
Left eye	10	10	10	10	40

Abbreviation: SD, Standard deviation.

Table 2 Corneal Subbasal Nerve Parameters of 80 Healthy Subjects, Classified into 4 Age Groups

	Age (Years)				Total
	20–30	>30–40	>40–50	>50–60
Number of nerves
Main trunks (No./frame)	4.58 ± 0.24	4.04 ± 0.27	4.71 ± 0.18	4.53 ± 0.31	4.47 ± 0.13
Main trunks (No./mm^2)	28.62 ± 1.50	25.25 ± 1.68	29.43 ± 1.12	28.31 ± 1.93	27.93 ± 0.81
Nerve branches (No./frame)	14.75 ± 0.47	15.93 ± 0.75	19.36 ± 0.80	16.53 ± 0.93	16.57 ± 0.38
Nerve branches (No./mm^2)	92.18 ± 2.93	99.56 ± 4.68	121.00 ± 1.33	103.31 ± 5.81	103.56 ± 2.37
Total nerves (No./frame)	19.33 ± 1.09	19.97 ± 1.81	24.07 ± 1.94	21.06 ± 1.65	21.04 ± 0.82
Total nerves (No./mm^2)	120.81 ± 6.81	124.81 ± 11.31	150.43 ± 12.12	131.62 ± 10.31	131.5 ± 5.12
Density of nerves
Main nerves (mm/mm^2)	11.35 ± 0.61	10.19 ± 0.69	11.89 ± 0.38	11.44 ± 0.66	11.22 ± 0.30
Nerve branches (mm/mm^2)	9.00 ± 0.39	8.95 ± 0.60	9.67 ± 0.77	9.00 ± 0.66	9.15 ± 0.30
Total nerves (mm/mm^2)	20.35 ± 0.69	19.14 ± 0.90	21.56 ± 0.83	20.44 ± 0.64	20.37 ± 0.39

Notes: Values are presented as mean ± standard error of mean (SEM). Independent t-test was performed to analyze the difference of subbasal nerve number and density between the age groups. Statistical significance when p < 0.05 compared between the age groups; all p >0.05.

Table 3 Grading of Corneal Subbasal Nerve Tortuosity of 80 Healthy Subjects, Classified into 4 Age Groups

Grading of Nerve Tortuosity	Age (Years)				Total
	20–30	> 30–40	> 40–50	> 50–60
Grade 0	–	–	–	–	–
Grade 1	4	4	1	2	11
Grade 2	10	11	7	4	32
Grade 3	3	4	8	5	20
Grade 4	2	2	5	8	17

Notes: The tortuosity of corneal subbasal nerves was graded in accordance with the classification proposed by Oliviera-Soto et al.

Figure 1 The bar graph demonstrates the patterns of corneal subbasal nerve tortuosity in different age groups.

Figure 2 Confocal images of corneal subbasal nerves obtained from 2 types of confocal microscope: (A) Laser scanning confocal microscope (LSCM) and (B) Slit-scanning confocal microscope (SSCM).