Agnieszka Bociek

Background/Objectives: Hemodialysis (HD) is the commonest life sustaining form of kidney replacement therapy in the world; however, this method of treatment have many adverse effects, and even a single HD session affects many organs, including the eyes. The aim of this study was to assess the effect of a single HD session on the ophthalmologic findings in patients with End-stage Renal Disease (ESRD). The second aim of the study was to examine the correlation of these changes with each other and between changes in systemic stressors related to the HD session. Methods: This was a single-center cross-sectional observational study conducted on 32 patients undergoing HD. Selected parameters of the anterior and posterior segment of the eye as well as systemic parameters were assessed before and after a single HD session. Results: Best corrected visual acuity (BCVA) improved, and lens thickness (LT), axial length (AXL), average macular thickness (MT), central MT and total vessel density (VD) of the deep capillary plexus DCP increased significantly after a single HD session. The Schirmer test results, tear break up time (TBUT), anterior chamber depth (ACD), central and average choroidal thickness (CT) decreased significantly after HD. Body weight loss was the only significant systemic change. Decrease in TBUT correlated positively with Schirmer’s test results decrease. Increase in CCT correlated positively with AXL increase. Decrease in central and average CT correlated positively with IOP decrease. Increase in central MT correlated positively with increase in average MT. Decrease in central CT correlated positively with average CT decrease. Change in VD of the SCP correlated positively with change in VD of DCP. Apart from the positive correlation between SBP change and Schirmer’s test results change, there were no correlations between systemic and ophthalmic parameters changes. Conclusions: Our study showed that HD affected the parameters of the anterior and posterior segments of the eye. Numerous correlations between these changes suggest that they are interrelated and represent the complex response of the eye to the HD process.

Haemodialysis (HD) is currently the most commonly used method of renal replacement therapy. The process of dialysis involves numerous changes that affect many systems, including the eye. The changes occurring in the course of HD may affect the ocular parameters, such as intraocular pressure, central corneal thickness, retinal thickness, retinal nerve fibre layer thickness, and choroidal thickness (CT). The choroid, being one of the most vascularized tissues, is characterized by the highest ratio of blood flow to tissue volume in the entire body, may be particularly susceptible to changes occurring during HD, and at the same time reflect the microcirculatory status and its response to HD. Patients with end-stage renal disease subjected to dialysis are highly susceptible to systemic microvascular dysfunction. Moreover, it is considered that the process of HD itself contributes to vascular dysfunction. Nowadays, thanks to the development of imaging techniques, the widely available optical coherence tomography (OCT) tests allow for the assessment of CT, while OCT-angiography allows for a quick, non-invasive, and repeatable assessment of the condition of retinal and choroidal microcirculation, which significantly expands our knowledge regarding the reaction of ocular microcirculation due to HD. The assessment of both retinal and choroidal circulation is even more attractive because retinal circulation is autoregulated, while choroidal circulation is mainly controlled by extrinsic autonomic innervation. Thus, assessment of the choroidal response to an HD session may provide the possibility to indirectly evaluate the functions of the autonomic system in patients subjected to HD. At a time when the importance of microcirculation in systemic and renal diseases is becoming increasingly evident, the assessment of ocular microcirculation appears to be a potential biomarker for assessing the condition of systemic microcirculation. In this work, we present a review of the literature on the effect of the HD session on CT and the retinal and choroidal microcirculation.