Résumé
The aim of this study was to show that ganglion cell thicknesses (in µm) using Optical Coherence Tomography (OCT) Canon HS-100 are lower in territories corresponding to visual field (VF) deficits, with respect for the vertical and horizontal meridian, in patients with chiasmatic or retrochiasmatic damage, compared with the same areas in healthy subjects.Methods: this study was retrospective, including all patients who had a visual field that respected the vertical meridian and a neuro-ophtalmological evaluation of patients with chiasmatic and retrochiasmatic cerebral lesions between November 2016 and February 2023. We analysed the topographic alterations and the vertical and horizontal segmentation of the ganglion cells complex (GCC) using Canon HS-100 OCT machine (SD-OCT) in linked with this visual field deffect pattern. GCC values of patients were compared with healthy controls appaired on age, sex and ethnic group. Macular SD-OCT scans were obtained from 62 eyes of 31 patients and we compared it with 62 eyes of 31 controls.Results: the GCC thickness in patients significantly differed in homolateral and contralateral eyes in affected quadrants (P<0.0001 for both), in adjacent quadrant in affected hemifield (respectively P=0.0074 and P=0.0015) and in adjacent quadrant in unaffected hemifield (P=0.0007), except for the adjacent quadrant in unaffected side of the controlateral eye (P=0.0544) compared with controls. The mean difference between cases and controls decreased from the "affected quadrant" (-17.26 µm in homolateral eye; -21.69 µm in contralateral eye), the "unaffected quadrant in affected side" (-10.87 µm in homolateral eye; -14.07 µm in contralateral eye) to the "unaffected quadrant in unaffected side" (-8.32 µm in homolateral eye; -4.21 in contralateral eye).Conclusion: GCC thickness is known to decrease earlier than RNFL in pregeniculate and retrogeniculate lesions. Several studies have shown GCC systematization with visual field in these cases, but none in both. Thanks to its macular mapping, OCT Canon HS-100 offers a clearsighted idea of the location of the cerebral attempt, thanks to a non-irradiant, reproductive and cheap exam when associated with a visual field.