Abstract:

Objective: Hypothyroidism, in which systemic vascular changes can be seen, is an endocrine system disease characterized by insufficient secretion of thyroid hormones. In this study, it was aimed to quantitatively investigate retinal and choroidal vascular changes in patients with primary hypothyroidism during the hypothyroid and euthyroid periods by optical coherence tomography angiography (OCTA). Materials and Methods: Forty eyes of 20 patients with overt or subclinical hypothyroidism requiring treatment were included in the study. The patients were evaluated with OCTA in the euthyroid period after hypothyroid and levothyroxine treatment. Foveal avascular zone (FAZ) and choriocapillaris flow (CF) values, superficial capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillary plexus (RPCP) vascular density data were obtained with the OCTA device. Results: There was no statistically significant difference between hypothyroid and euthyroid periods in the vascular density values of SCP, DCP and RPCP (p>0,05 for all). On the other hand, statistically significant increases were observed in the euthyroid period compared to the hypothyroid period in CF measurements made using 1,2 and 3 mm scanning patterns (p=0,037; p=0,035; p=0,021 respectively). While 1 and 2 mm CF values were positively correlated with fT4 levels in the euthyroid period (r=0,596; p<0,001 and r=0,402; p=0,012); a negative correlation was found between 1 mm CF measurements and patient age and TSH levels in the euthyroid period (r=-0,380; p=0,016 and r=-0,351; p=0,031). Conclusion: In this study, increased CF rate was found in the euthyroid period compared to the hypothyroid period. It is thought that these changes may be related to the systemic vascular changes that can be seen in hypothyroidism, and the evaluation of ocular flow with OCTA is important in detecting possible vascular effects in patients with hypothyroidism.

Keywords: