[Morphological changes of corneal subbasal nerve plexus in patients with ocular blunt trauma by in vivo confocal microscope].

OBJECTIVE

To evaluate morphological changes of corneal subbasal nerve plexus in patients with ocular blunt trauma using in vivo confocal microscope.

METHODS

A prospective study. Twenty-three consecutive zone 2 or zone 3 monocular contusion outpatients from the same ophthalmologist in the Affiliated Eye Hospital of Wenzhou Medical College were included in this study from December 2009 to December 2010. The 23 injured eyes divided into trauma group, and the contralateral 23 normal eyes were divided into control group. In vivo confocal microscope (IVCM) was performed in both groups at the first week after injury, and in trauma group at the first and the third month after injury. The main parameters for analyzing were corneal subbasal nerve plexus density, nerve trunks, nerve branching, total nerve number, and nerve tortuosity. Data were analyzed using a paired t-test and Wilcoxon signed-rank test to compare the difference of parameters between the control group and each time point of trauma group. A repeated measures analysis of variance (ANOVA) was used to analyze data on the three time points in the trauma group.

RESULTS

All parameters of trauma group were changed significantly over time (F values: 16.272, 24.138, 63.393, 68.122, 91.463, all P values < 0.01) . Corneal subbasal nerve plexus density, nerve trunks, nerve branching, total nerve number were significantly decreased at the first week [(624.0 ± 109.9) µm/frame, 1.66 line/frame, 6.70 line/frame, 8.45 line/frame)] compared with control group [(1677.9 ± 87.1) µm/frame, 4.80 line/frame, 8.98 line/frame, 13.80 line/frame) (t = 8.998, 9.301, 9.119, 12.969; all P < 0.01)], and showed a continued downward trend with time. However, nerve trunk showed no significant changes at the first week (1.66 line/frame) and the first month (2.31 line/frame) (t = -1.518; P = 0.143). Nerve tortuosity was significantly increased at the first week (1.66) compared with control group (1.00) (t = -6.879; P < 0.01) , and then kept increasing gradually. At the first month after injury, the nerve tortuosity (3.20) was more obvious than the first week (P < 0.01) , and nerve regeneration could be observed. At the third month, the values of each parameters were gradually approaching levels of control group. Nerve trunks (4.00 line/frame), nerve branching (8.69 line/frame), total nerve number (13.26 line/frame) and nerve tortuosity (1.00) of trauma group showed no significant difference compared with control group (t = 3.117, 1.703, 3.325, -1.837; P = 0.079,0.792,0.392,0.392) , but nerve density [(1064.3 ± 93.3)µm/frame] was still less than control group (t = 5.736; P < 0.01). Injury of different zone showed no significant influence on all the parameters in trauma group (F values:0.119,0.032,0.296,0.053,0.143;P values: 0.733,0.859,0.592,0.821,0.709).

CONCLUSIONS

IVCM can clearly display the histological features of corneal subbasal nerve plexus in patients with ocular blunt trauma. Corneal subbasal nerve plexus were morphologically abnormal within 3 months after injury, and gradually underwent from atrophy to regeneration over time.