Changes in subfoveal choroidal thickness and choroidal extravascular density by spectral domain optical coherence tomography after haemodialysis: a pilot study

Aims To examine the changes in the subfoveal choroidal thickness (SECT) and choroidal density using spectral domain optical coherence tomography (SD-OCT) before and after haemodialysis (HD). Methods 28 eyes of 19 patients with chronic renal failure (CRF) undergoing HD were included. Ophthalmologic examinations including SD-OCT were performed 1 h before and after HD. The SECT was measured manually using Image J software, and the relationships between the change in SECT and in the systemic parameters after HD were evaluated. The changes in choroidal extravascular density of the OCT image after HD were evaluated by comparing brightness value obtained with Adobe Photoshop software. Results The mean SECT of all eyes increased significantly from 276.94 +/- 58.73 mu m to 288.29 +/- 65.57 mu m (p=0.003). In the univariate generalised estimating equation (GEE), the SECT increased significantly after HD (p=0.006). After adjusting for age, gender and other significant factors in univariate analysis, the SECT increased significantly after HD (p=0.032). The decrease in systolic blood pressure (SBP) was associated with the increase in SECT (p=0.013). The choroidal extravascular density of OCT image increased after HD (p<0.001) and the mean change was 12.35 +/- 9.72. Conclusions In the SD-OCT image, the SECT became thicker and the choroidal extravascular density increased after HD in patients with CRF. The decrease in SBP after HD was associated with an increase in SECT. The choroidal autoregulatory control of ocular hemodynamic change and shifting of fluid and molecules between the blood and choroidal interstitium might be involved in the mechanism of these choroidal changes.