[Four-year changes in ganglion cell complex thickness in homonymous hemianopia].

PURPOSE

Aquired transsynaptic retrograde degeneration of the human visual system can be identified using magnetic resonance imaging (MRI) and optical coherence tomography (OCT), which can reveal optic tract atrophy, retinal nerve fiber layer loss, and ganglion cell complex (GCC) thinning. We investigated GCC changes in the first 4 years following post-geniculate lesions.

METHODS

Nine patients with congruous homonymous hemianopia were scanned with OCT. A 6-mm circle centered on the macula was divided vertically into hemianopia (H) and unaffected (U) sides. GCC and retinal thicknesses were calculated using an average for both eyes and compared with the hemianopia/unaffected side (H/U) ratio. The relationship between the H/U ratio of GCC and time elapsed since occipital damage was evaluated.

RESULTS

The average GCC thicknesses was 89.1 and 96.6 microm, and of the retina 295.7 microm and 292.7 microm in the H and U sides, respectively. The H/U ratio of GCC at 0.92 was significantly lower than of the retina at 0.99 (p=0.042). Regression analysis revealed a negative linear relationship (linear regression r= -0.868, p= 0.012) described by the equation: H/U ratio of GCC = 0.99 - 0.004 x elapsed time (months).

CONCLUSION

For 4 years following post-geniculate damage, GCC on the hemianopia side decreased approximately 5% per year while the retinal thickness was almost unchanged.