Choroidal and macular thickness changes in type 1 diabetes mellitus patients without diabetic retinopathy

To explore choroidal thickness (ChT) and retinal thickness (RT) changes in patients with type 1 diabetes mellitus (DM).

Sixty patients with Type 1 DM and 60 age- and sex-matched healthy controls were included in this prospective case-control clinical study. All patients underwent a complete ophthalmological examination. ChT of each participant was measured at the fovea and horizontal nasal and temporal quadrants at 500-µm intervals to 1500 µm from the foveola using spectral-domain optical coherence tomography (SD-OCT). Age, gender, disease duration, serum glycosylated hemoglobin (HbA1c), fasting glucose level, axial length (AL) and refractive error were noted and analyzed.

Mean disease duration, mean HbA1c and mean fasting blood glucose in diabetic patients were 6.1±2.8 years, (8.9±0.9)% and 287.5±69.1 mg/dl, respectively. Age, gender, AL, spherical equivalent differences between the patients and subjects were insignificant (p>0.05). Subfoveal ChT, nasal quadrant ChT measurements, temporal 1500 µm and mean nasal ChT were significantly lower in diabetic patients (p<0.05 for all). Temporal 500 µm and 1000 µm ChT measurements, mean temporal ChT, average ChT, central macular thickness and average macular thickness did not differ significantly between the groups (p>0.05 for all).

This study showed that there is choroidal thinning in young Type 1 diabetic patients with early period of disease duration without diabetic retinopathy nor any other systemic diseases. Choroidal changes in type 1 DM seem to begin at nasal and distal temporal retina. These results need to be verified by larger and longitudinal studies.