Is type 2 macular telangiectasia a bilateral and symmetrical disease entity?

Purpose: To study the inter-eye asymmetry in cases diagnosed with type 2 macular telangiectasia (MacTel).Methods: Herein, type 2 MacTel cases were staged as per Gass and Blodi classification with multiple imaging techniques. Based on disease stage symmetry, two groups identified. Group 1: Symmetrical stage and Group 2: Asymmetrical stage MacTel disease. Prevalence, demography, and clinical features of MacTel cases showing inter-eye asymmetry were analyzed.Results: Two hundred and eighty eyes of 140 patients diagnosed clinically with type 2 MacTel (84-Group 1 and 56-Group 2) were evaluated. Eighty-nine (64%) were female, and the median age of the entire cohort was 62.5 years (inter-quartile range: 57.0-68.75). MacTel disease with asymmetric stage was seen in 56 (40%) of the 140 patients. At presentation, a two-stage difference was noted in 46% (n = 26) of the patients with asymmetrical MacTel disease. A 10% conversion from symmetrical to asymmetrical disease stage was noted at the final visit. Of the 280 eyes evaluated for type 2 MacTel disease, 12 (4%) eyes showed no findings suggestive of MacTel on clinical examination and fluorescein angiography, optical coherence tomography (OCT), and OCT angiography when available and were labeled as unilateral type 2 MacTel disease.Conclusions: Type 2 MacTel can show inter-eye disease stage asymmetry. Unilateral type 2 MacTel disease is a distinct stage in MacTel which would need further evaluation and consideration while staging.