Effect of hemodialysis (HD) on intraocular pressure, ocular surface, and macular change in patients with chronic renal failure

The main objective of hemodialysis (HD) is to correct the excessive accumulation and abnormal distribution of body fluid. Therefore, changes in the systemic hemodynamic parameters and in the ocular fluid volume and composition can occur during a single HD session. The aim of this study is to evaluate the short-term changes in the ophthalmologic findings after HD. Thirty eyes of 30 patients with chronic renal failure (CRF) undergoing HD were analyzed. The subjects were categorized into two groups according to the cause of CRF. Detailed ophthalmologic examinations were performed immediately before and after HD. The relationships between the systemic hemodynamic changes and the ophthalmologic changes during a single HD session were evaluated. The results show that a body fluid correction after HD involves a change in the plasma colloid osmotic pressure. The mean intraocular pressure (IOP) decreased after HD with a mean decrease of 2.4 +/- 2.1 mmHg and the central corneal thickness decreased with a mean change of 6.9 +/- 5.4 mu m. After HD, the ocular surface changed significantly; the tear break-up time (TBUT) and basal tear secretion (Schirmer's test) decreased, whereas the keratoepitheliopathy score increased. The macular thickness measured by spectral domain optical coherence tomography (SD-OCT) decreased after HD. The mean decrease in the central subfield thickness was 7.4 +/- 9.9 mu m. The ocular surface changes after HD affected the visual acuity and examination quality. A significant correlation was found between the changes in the systemic hemodynamic parameters and those in the ophthalmologic findings, except for the retinal thickness. The changes in the ophthalmologic findings after HD were consistent and significant in all CRF subjects. These changes correlated with the increase in plasma colloid osmotic pressure. HD can correct the volume and composition of ocular fluid. Therefore, it can affect the ophthalmologic findings in a short period of time. In addition, for good examination quality, it is recommended that an ophthalmologic examination in CRF patients be performed on a non-dialysis day or prior to HD on a dialysis day. Furthermore, for accurate comparison of examination results, the time interval from an HD session to an ophthalmologic examination must be considered.