Investigation of changes in the biometric structure of the anterior chamber and intraocular pressure in patients with chronic renal failure after hemodialysis

Abstract

Objective To investigate changes in the width of the iridocorneal angle in the four quadrants (nasal, temporal, superior, inferior), central anterior chamber depth, lens thickness and intraocular pressure (IOP) in patients with chronic renal failure after hemodialysis. Methods Retrospective case series study. Thirty-five patients (70 eyes) with chronic renal failure were measured with tonometry (IOP), A/B scan (lens thickness) and ultrasound biomicroscopy (central anterior chamber depth, the trabecular iris angle and four directions of the angle opening distance) before and after hemodialysis. The patients were divided into 2 groups based on gonioscopy results: a narrow angle group (14 eyes) and an open angle group (56 eyes). IOP was measured in the 2 groups before and after hemodialysis. The patients' blood urea nitrogen (bun), creatinine (scr), albumin (alb),plasma osmotic pressure and dehydration were also checked before and after hemodialysis. All changes in the parameters were analyzed with a paired t test. Results IOP increased significantly in 35 patients (70 eyes) after hemodialysis (t=-3.389, P＜0.05). Central anterior chamber depth (t=8.043,P＜0.01), iridocorneal angle width (t=4.637, 8.893, 3.575, 3.436, P＜0.01 for all), and angle opening distance (t=3.122, 5.372, 3.838, 2.915, P＜0.01 for all) in 35 patients decreased, with the lens becoming significantly thicker (t=-9.132, P＜0.01) after hemodialysis. The IOP in narrow angle eyes (14 eyes) increased significantly (t=-0.045, P＜0.01) after hemodialysis while the IOP in open angle eyes (56 eyes) showed no significant change (t=-9.515, P＞0.05). Bun, scr and plasma osmotic pressure decreased in 35 patients (t=16.075, 13.676, 113.063, P＜0.01 for all) and alb increased (t=-7.756, P＜0.01) after hemodialysis. Conclusion Due to the movement of liquid in eyes cause by the osmotic pressure gradient after hemodialysis, the eyes of patients with chronic renal failure are characterized by a shallower central anterior chamber depth, a narrower iridocorneal angle width and a thicker lens. In addition, the IOP of narrow angle eyes increase significantly. As a result, it is recommended that the anterior chamber structure of patients with chronic renal failure should be checked and patients should receive appropriate treatment before hemodialysis. Key words: Renal dialysis; Anterior chamber; Lens,eyes; Intraocular pressure