Abstract
Purpose :
Homonymous ganglion cell layer (GCL) thinning has been reported in homonymous hemianopsia caused by post geniculate pathology and is presumed due to retrograde trans-synaptic degeneration. We observed that this finding is not universal. In this study we looked at patient variables that are associated with this finding.
Methods :
A retrospective review was performed on all patients seen at Duke from 1/1/2010 to 12/1/2015. Relevant patients were identified by the ICD code for homonymous hemianopsia then matches were screened for patients who had macular SD-OCT (Heidelberg) and HVF 24-2 SITA Fast protocol on the same date. Patients were also required to have appropriate neuro-imaging to identify geniculate vs. pre-geniculate pathology. Data collected included: age, sex, pathology, location of pathology (occipital, temporal, and/or parietal and thalamic involvement vs. not), lesion type (ischemic vs. non-ischemic), homonymous GCL thinning on OCT vs. not, OCT timing after insult (<2 years or ≥ 2 years), center sparing on HVF vs. not. Chi square analyses of patients with and without homonymous GCL thinning were performed in order to determine whether significant differences in the aforementioned characteristics existed between these groups. Excluded were eyes with ocular pathology that might affect GCL or RNFL. All MRI scans and segmented macular OCT were reviewed in a masked fashion.
Results :
Included were 32 subjects, age 41.88 ± 27.3 years. Homonymous thinning of GCL was correlated with pathology older than 2 years (p = 0.03). Homonymous thinning was not statistically dependent on age at diagnosis (p = 0.64), lesion location (occipital/temporal/parietal, p = 0.36, 0.30, 0.96), thalamic involvement (p = 0.12), or lesion type (ischemic vs. non-ischemic, p = 0.40). Homonymous thinning was independent of difference in average RNFL between eyes (p = 0.84). There was also no association between homonymous thinning on OCT and center sparing on HVF (p = 0.89).
Conclusions :
Post-geniculate pathology associated with development of homonymous GCL thinning was mostly dependent on the duration of lesion. Further prospective studies with serial follow-up might help elucidate the development of this finding.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.