Type 1 diabetes (T1D) is one of the most prevalent endocrinological diseases among children and young adults, with a growing incidence rate reaching up to 2.9 new cases per year per 100 000 persons below 15 years of age. We report the rare case of a 20-year-old female patient with T1D, hemoglobin D (HbD) heterozygote variant and high myopia of -10,00 spheric diopters and describe the retinal microvascular alterations visible on OCT angiography (angio-OCT). The patient also presented severe stature deficit (less than 3 standard deviations) and delayed puberty, which could not be explained only by suboptimal glycemic control, indicated a possible hypopituitarism. The HbA1c level evaluated with high performance liquid chromatography (HPLC) method was 6.5%, a falsely low value due to the HbD hemoglobinopathy. On ophthalmic evaluation the angio-OCT scan showed the following retinal microvascular alterations for the RE: the FAZ area vas 0.39 mm2, the FAZ perimeter was 2.88 mm and the circularity index was 0.58; for the LE: the FAZ area vas 0.34 mm2, the FAZ perimeter was 3.21 mm and the circularity index was 0.41. Clinicians should consider high performance retinal screening methods such angio-OCT evaluation for young T1D patients, especially for those with associated pathologies like high myopia and hemoglobinopathies. Moreover, multiple evaluation methods of the HbA1c values are mandatory as hemoglobinopathies can interfere with HbA1c assay methods accuracy.