Morphological Changes of Corneal Endothelial Cells in Patients With Blast-Induced Traumatic Brain Injury

Abstract

Purpose: : To determine morphological changes in corneal endothelial cells in a population of veterans with traumatic brain injury (TBI) secondary to combat blast.

Methods: : In a prospective observational study we examined 37 consecutive inpatients at a VA Polytrauma Rehabilitation Center with the diagnosis of combat-related TBI caused by blast exposure with or without known ocular or visual injury; penetrating eye injuries were excluded. Stanford IRB and VA Research Committee approvals were obtained. Corneal endothelium was assessed and recorded at all visits by non-contact automated specular microscopy (Konan SP-900). One hundred cells were manually marked and analyzed with Center Method by two examiners in study patients and an age, gender and refraction-matched control group (n=10). Endothelial cell density (ECD) in cells/mm², the coefficient of variation (CV), and the fraction of six-sided cells (6A) were used for statistical analysis (SPSSStatistics 17.0).

Results: : Mean age was 26 years for study participants and 31 for controls. Mean interval between the date of blast and initial clinic visit was 12.8 months (range 0.4 to 84.0). Six patients had one eye enucleated. The mean ECD for the TBI patients at first visit was OD 2448 (n=35), OS 2591 (n=33) and at follow-up OD 2378 (n=17), OS 2529 (n=17); while the mean ECD for controls was OD 2764 (n=10), OS 2694 (n=10). The mean CV for the TBI patients was OD 35.0, OS 34.9 at first visit and OD 37.3, OS 35.2 at follow up; and OD 33.6, OS 33.4 for the controls. The mean 6A in the TBI patients was OD 57.2, OS 58.7 at first visit and OD 55.5, OS 60.4 at follow up and OD 63.2, OS 62.4 in the control group.

Conclusions: : There was no statistically significant change in ECD, CV and 6A between the two visits in the TBI group. The ECD and 6A were lower and the CV higher in the blast group compared to the controls. Three TBI patients had one eye ECD between 1300 and 1500 and the other eye between 2500 and 2700. In these patients the ECD loss was related to the blast direction but not to the TBI level. Further studies are required to assess correlations affecting endothelial cell alteration.

Keywords: cornea: endothelium • trauma • cornea: clinical science