Right-angled vessel characteristics in different stages of type 2 macular telangiectasia (MacTel)

Purpose: To study right-angled vessels (RAV) in disease progression and macular neovascularization in type 2 macular telangiectasia (MacTel) eyes.

Methods: This retrospective image analysis study examined type 2 MacTel patients' multicolour® and OCT imaging records from January 2015 to March 2023. Age, gender, laterality, visual acuity, systemic disease, and follow-up duration were recorded. RAV characteristics were assessed using OCT and multicolour® images. This study examined RAV characteristics and type 2 MacTel disease stage.

Results: In total, 270 eyes of 146 patients (97 females, 66%) with a mean age of 60.77 ± 9.34 years were studied. 153 (57%) eyes showed RAV. The non-proliferative stage of type 2 MacTel had either no RAV or a normal-calibre right-angled vein, while the proliferative stage had a right-angled artery and a dilated or normal-calibre RAV [p < 0.001]. RAV characteristics differed at the final follow-up (p < 0.001). 11 eyes transitioned from non-proliferative to proliferative after a median period of 26 months (range: 5-96 months). RAV characteristics changed from a normal calibre right-angled vein at presentation to a normal calibre vein and artery in 6 (55%) eyes and to a dilated vein and artery in 5 (45%) eyes respectively.

Conclusion: RAV characteristics may indicate type 2 MacTel stages. A right-angled artery in type 2 MacTel may indicate proliferative disease.