Abstract
Purpose: :
To evaluate changes in endothelial cell density (ECD), central corneal thickness (CCT) and best spectacle-corrected visual acuity (BSCVA) in normal eyes of US Army soldiers who sustained otherwise serious combat blast injuries.
Methods: :
In this retrospective case series US soldiers with significant blast injury to the head, face, and fellow eye were examined serially. Endothelial cells were counted using confocal microscopy (Confoscan4, Nidek Inc.). After image acquisition, a region of interest (ROI) was selected for manual and automated endothelial cell analysis. Manual counts were performed marking each complete cell in the ROI. Cells cut by the top and left borders of the ROI were also counted and those cut by the bottom or right border were omitted, per manufacturer guidelines. Automatic counts were performed with manual editing to correct recognition of cells and to obtain degree of polymegathism and pleomorphism. CCT was measured using anterior segment OCT (Visante, Carl Zeiss Meditec). High-contrast Snellen acuity was determined with best spectacle correction and converted to logMAR for analysis. A paired sample t-test was used to compare the initial and final values of ECD (manual and auto), polymegathism, pleomorphism, CCT, and BSCVA. A P-value of <0.05 was considered statistically significant.
Results: :
19 eyes/soldiers, mean age 28.8 ± 8.2 years (range 22 to 50) were followed a mean of 357 days (range 115 to 926) days post injury. There was no significant change between initial and final ECD by either automated cell count (2726± 315 vs. 2638± 495 cell/mm2, P=0.235, mean number of cells counted= 59) or manual cell count (2687± 311 vs. 2603± 486 cell/mm2, P=0.262, mean number of cells counted= 77). Nor was there a change in polymegathism (31% vs. 33%, P= 0.131), pleomorphism (57% vs. 55%, P=0.548), or CCT (524 vs. 525µm, P=0.924). BSCVA improved significantly between the initial and final visit (LogMAR -0.04± 0.09 to -0.08± 0.06, P=0.034).
Conclusions: :
Blast trauma did not indirectly affect ocular health of an uninjured eye via concussive force to the cornea - there was no significant change in cell density, cell morphology, corneal thickness, or vision during the follow-up period averaging over 350 days from injury, suggesting a good prognosis in eyes not directly injured by the blast. The most significant threat to the eye remains penetrating trauma from fragments and debris generated from blasts.
Keywords: cornea: endothelium • trauma