Multimodal Imaging Findings and Treatment with Dexamethasone Implant in Three Cases of Idiopathic Macular Telangiectasia Type 1

This is a report of 3 patients diagnosed with idiopathic macular telangiectasia type 1 (MacTel 1) at Medical Retina Center of the University of Eye Clinic of Genova and then prospectically followed for a mean time of 26 months between 2016 and 2019. It is the first report of patients affected by MacTel 1 treated with dexamethasone (DEX) implant as a first choice of treatment. Aim of our study is to better characterize the disease using a multimodal wide-field imaging and to determine efficacy of DEX implant on MacTel 1 in terms of central macular thickness (CMT) and best-corrected visual acuity (BCVA). MacTel 1 is a rare unilateral disease, characterized by telangiectatic retinal capillaries, cystoid macular edema, and lipid deposition occurring temporal to the fovea. Patients underwent a comprehensive ophthalmic examination, BCVA, swept-source optical coherence tomography (SS-OCT), SS-OCT angiography (SS-OCTA), ultra-widefield (UWF) color, and fluorescein angiography (FA) fundus photograph. All the patients presented monolateral reduced BCVA and macular edema with increased CMT evaluated by SS-OCT. With SS-OCTA, we showed that the telangiectasia-associated vascular changes originate in the deep retinal vascular plexus and as a consequence macular edema and exudation develop causing vision loss. Furthermore, UWF imaging helped us to highlight vascular changes typical of Coats Disease at the far retinal periphery. All the patients were treated with DEX intravitreal implant, showing a decrease in CMT and a stabilization of visual acuity. Due to the recurrent nature of macular edema, patients underwent a mean of 4 DEX implants during the follow-up period. In order to address the clinical features of this uncommon disease avoiding diagnostic errors, it might be important to use a multimodal imaging approach. The anatomical and functional beneficial effects of DEX implant were well evident although transient.