Background The aim of the study was to detect the changes in retinal and choroidal vasculature via optical coherence tomography angiography (OCTA) by comparing the quantitative OCTA parameters in patients with and without myotonic dystrophies (DM). Material The cross-sectional study. Forty-one consecutive patients affected by DMs were enrolled. The inclusion criteria were molecular diagnosis of DM types 1 and 2. To avoid the age effect on microvascular changes and to justify a comparison between DM1 and DM2 patients, two control groups matched for sex and age were established. Results The vascular density was found to be significantly decreased in the DM groups compared to the controls in the macular, parafoveal and perifoveal zone of superficial capillary plexus ( p < 0.001 for the DM1 group, and p = 0.001, p = 0.005 and p = 0.026, respectively, for the DM2 group), as well as in the macular zone in the deep capillary plexus for DM1 ( p = 0.002) and deep macular and perifoveal zone for DM2 ( p = 0.007, p = 0.001, respectively). The foveal avascular zone showed no significant differences between DM1 and DM2 compared to their control groups ( p = 0.320 and p = 0.945, respectively). Conclusion Our results show that DM is associated not only with the classic pigmentary changes but also with superficial and deep retinal microvasculature abnormalities, suggesting that these changes may be related to local hypoperfusion. Optical coherence tomography angiography is a useful tool for the diagnosis and characterization of retinal changes in DM and should be part of the standard evaluation of these patients.
