Corneal sensitivity and morphology of the corneal subbasal nerve plexus in primary congenital glaucoma

Background

To quantify the corneal subbasal nerve density and the total number of nerve fibers in primary congenital glaucoma (PCG) and to evaluate their impact on corneal sensitivity.

Methods

Forty eyes of 26 PCG patients were compared with 40 eyes randomly selected from 40 non-glaucoma patients who populated the control group. Central corneal sensitivity (CCS) was assessed by means of Cochet–Bonnet esthesiometry. The mean subbasal nerve density and the total number of nerve fibers were quantified by laser-scanning confocal microscopy. Normality of data was assessed by Kolmogorov–Smirnov testing. Differences in parameters were assessed with Student''s t-test, while correlations with CSS were assessed with Pearson''s correlation.

Results

Significant differences were identified in the mean subbasal nerve density (2108±692 μm in PCG, 2642±484 μm in controls, P=0.003) and in the total number of nerve fibers (12.3±4.2 in PCG, 15.4±3.1 in controls, P=0.02). Both groups presented comparable mean CCS and tortuosity. Both groups presented strong correlations between CCS and mean nerve density (r=0.57 in PCG, r=0.67 in controls, all P<0.05), and between CCS and total number of nerve fibers (r=0.55 in PCG, r=0.56 in controls, all P<0.05).

Conclusion

PCG exerts significant changes in both the mean subbasal nerve density and the total number of nerve fibers. However, these changes do not appear to affect central corneal sensitivity.