AUTHOR=Kiraly Peter , Seitz Immanuel P. , Abdalla Elsayed Maram E. A. , Downes Susan M. , Patel Chetan K. , Charbel Issa Peter , Birtel Johannes , Mautone Luca , Dulz Simon , Atiskova Yevgeniya , Herrmann Philipp , Vrabič Nika , Jarc-Vidmar Martina , Hawlina Marko , Fischer M. Dominik TITLE=Morphological and functional parameters in X-linked retinoschisis patients–A multicentre retrospective cohort study JOURNAL=Frontiers in Medicine VOLUME=Volume 10 - 2023 YEAR=2024 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1331889 DOI=10.3389/fmed.2023.1331889 ISSN=2296-858X ABSTRACT=Introduction: X-linked retinoschisis (XLRS) is a potential target for gene supplementation approaches. To establish potential structural and functional endpoints for clinical trials, a comprehensive understanding of the inter-eye symmetry, relationship between structural and functional biomarkers, and disease progression is vital.In this retrospective multicentre study, 118 eyes of 59 XLRS patients with RS1 mutations were assessed. Information from centre databases included: RS1 variant; age at presentation; bestcorrected visual acuity (BCVA), central retinal thickness (CRT), macular volume (MV) at presentation and at the last follow up; full-field electroretinogram (ERG) findings; presence of peripheral retinoschisis and complications (vitreous haemorrhage, retinal detachment); treatment with systemic or topical carbonic anhydrase inhibitors (CAI).Results: Inter-eye symmetry revealed strong correlation in CRT (r=0.77; p<0.0001) and moderate correlations in MV (r=0.51, p<0.0001) and BCVA (r=0.49; p<0.0001). Weak or no correlations were observed between BCVA and structural parameters (CRT, MV). Peripheral retinoschisis was observed in 40 (68%), retinal detachment in 9 (15%), and vitreous haemorrhage in 5 (8%) patients, respectively. Longitudinal examinations (mean, 4.3 years) showed no BCVA changes; however, a 2 This is a provisional file, not the final typeset article reduction of the CRT (p=0.02), and MV (p=0.01) was observed. Oral and/or topical carbonic anhydrase inhibitors (CAI) treatment did not significantly alter the CRT (p=0.34).The XLRS phenotype demonstrates a strong CRT symmetry between the eyes within individual patients and stable BCVA over several years. BCVA exhibits a weak correlation with the morphological parameters of retinal thickness (CRT MV). In our cohort, longitudinal morphological and functional changes were not significant, likely attributed to the short average follow-up period. Furthermore, CAI treatment didn't influence both morphological and functional outcomes 1