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

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

Methods: 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.

Results: 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).

Conclusion: 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.