Does size of telangiectasia on optical coherence tomography angiography influence vision in eyes with type 2 macular telangiectasia?

PURPOSE

To study the influence of dimensions of macular telangiectasia (MacTel) on enface optical coherence tomography angiography (OCTA) on vision and clinical parameters in eyes with MacTel type 2.

METHODS

MacTel was classified based on OCTA location, i.e. either temporal to the fovea (grade 1), or spread nasally (grade 2), or circumferentially (grade 3), or the presence of neovascular-like tissue in the outer retina-choriocapillary complex (ORCC) (grade 4). On enface images, the maximum dimensions of the MacTel in the deep plexus were noted using calipers by a single experienced observer.

RESULTS

Ninety-eight eyes of 49 patients with MacTel with a mean visual acuity was 0.46 + 0.26 logMAR and mean macular thickness of 202 ± 132 μ were included. Based on OCTA, grade 3 MacTel (n = 35, 36%) was the commonest followed by grade 4 (n = 28, 29%). The mean maximum vertical diameter of the MacTel was 2019 + 753 μ, and every 500 microns increment in vertical diameter of the MacTel was associated with a half-line drop in vision (95%CI = 0.005 to 0.08 logMAR, P = 0.03). Vision gradually reduced with increment in OCTA grades of MacTel from grade 1 to 3; however, the trend was not maintained in grade 4 MacTel, which showed better vision and lesser degenerative cysts.

CONCLUSION

Larger telangiectasias were associated with significantly lower vision in MacTel. Eyes with deeper telangiectasia involving ORCC have better vision and evidence of far lesser neurodegeneration than type 3 disease, suggesting that this may not be part of the continuum and does not represent neovascularization.