Corneal Alterations in Patients with Osteogenesis Imperfecta: An in vivo Corneal Confocal Microscopy Study

Pietro Mangiantini,1,* Fabiana Mallone,1,* Mattia D’Andrea,1 Lorenzo Albanesi,1 Luca Lucchino,1 Luca Celli,2 Mauro Celli,2 Alessandro Lambiase,1 Antonietta Moramarco1, †1Department of Sense Organs, Sapienza University, Rome, Italy; 2Department of Pediatrics, Center for Congenital Osteodystrophy, Sapienza University, Rome, Italy*These authors contributed equally to this work†Dr Antonietta Moramarco passed away on 24 March 2024Correspondence: Alessandro Lambiase, Department of Sense Organs “Sapienza” University of Rome, Viale del Policlinico 155, Rome, 00161, Italy, Tel +390649975305, Fax +390649970364, Email [email protected]: Osteogenesis imperfecta (OI) is a rare hereditary disorder of the connective tissue. Despite recent attention to corneal abnormalities in OI, understanding remains limited. This study aimed to comprehensively evaluate corneal changes in a large sample of OI patients compared to controls using in vivo confocal microscopy (IVCM).Patients and Methods: Nineteen OI patients (mean age: 34.0 ± 16.00 years; 9 females, 10 males) and 20 healthy controls (mean age: 35.5 ± 12.00; 12 females, 8 males) were included, matched for age and gender. The integrity of corneal cell layers, with a focus on Bowman’s layer and sub-epithelial stroma, was evaluated. Additionally, we conducted a quantitative analysis of the corneal sub-basal nerve plexus (CSNP), measuring nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), and dendritic cells (DCs) density. Clinical parameters including blue discoloration of the sclera, corneal thickness and sensitivity were also evaluated.Results: Bowman’s layer alterations were observed in 42.11% of OI patients. NFD was significantly reduced in OI patients (27,3± 6.98 vs controls 37.85± 13,74 fiber/mm2; p-value=0.005). NBD and NFL were lower in OI patients but did not reach statistical significance (p=0.650 and p=0.120, respectively). DCs density was higher in OI patients than controls (11,37 ± 12.79 vs 2.09± 2,91 cells/mm2; p-value < 0.001). Corneal thickness and sensitivity were significantly reduced in OI patients compared to controls (p< 0.001, p=0.001, respectively). OI patients with blue sclera or abnormal Bowman’s layer exhibited even lower central corneal thickness (CCT) (p=0.010, p=0.005, respectively).Conclusion: OI patients demonstrated Bowman’s layer abnormalities, neuropathic changes and higher inflammatory cell count. These results suggest potential corneal complications, and hold promise for diagnostic applications and intervention strategies in OI.Keywords: osteogenesis imperfecta, OI in vivo confocal microscopy, IVCM corneal sub-basal nerve plexus, CSNP corneal nerves, dendritic cells, DCs