Changes in intraocular pressure, and corneal and retinal nerve fiber layer thickness during hemodialysis

The aim of this study is to evaluate the changes in intraocular pressure (IOP), central corneal thickness (CCT), and retinal nerve fiber layer thickness (RNFLT) in patients with chronic renal failure undergoing hemodialysis (HD). A complete ophthalmological examination together with IOP, CCT, and RNFLT measurements were performed for each patient both before and after HD sessions. RNFLT parameters were detected by scanning laser polarimeter. Total body weight and serum osmolality were also measured. Only the left eyes were recruited for statistical analysis. Thirty-three eyes of 33 patients were enrolled in the study. Mean IOP decreased from 14.7 +/- 3.1 to 13.4 +/- 2.4 mmHg after HD (paired t test, P = 0.005). Mean CCT also decreased significantly after HD, from 556.5 +/- 33.5 to 550.2 +/- 34.6 mum (paired t test, P = 0.002). CCT change in the left eyes was found to be correlated with total body volume loss (Pearson correlation test, R = 0.391 and P = 0.030). Considering RNFLT parameters before and after HD, no significant alterations were detected by scanning laser polarimeter (paired t test, P > 0.05). We conclude that IOP may decrease to some extent after HD. CCT may be affected by fluid loss after HD sessions, with a resultant decrease in corneal thickness. In patients with chronic renal failure undergoing HD, RNFLT parameters can be measured as in healthy individuals. Underestimation of intraocular pressure values after HD sessions should be taken into account, especially in patients with chronic renal failure.