Asessment of Visual Acuity Changes Across a Dialysis Unit Population.

Abstract

Purpose : Haemodialysis (HD) patients report visual disturbances associated with dialysis sessions - the causes for these symptoms are poorly documented and understood. We performed a prospective, clinical study with the aim to describe and assess the change in visual acuity (VA) of patients receiving HD.

Methods : All patients receiving chronic HD at our centre between 01.03.2015 and 31.05.2015 were invited to participate. Those registered blind were excluded. VA of each eye was assessed using a Snellen eye chart at 3m before and after a single mid-week dialysis session. The Snellen result was converted to a decimal score in order to allow categorization according to the World Health Organisation (WHO) classification of visual loss into normal, mild, moderate and severe. Patients’ subjective perceptions of visual disturbances and dialysis-details were recorded.

Results : 140 patients (271 eyes) were suitable for inclusion. 88 were male, median age was 64 years (range 25-90) and median dialysis vintage was 50 months (range 1-315). Best eye pre dialysis assessment revealed 36% (n=50) of patients had normal vision, 40% (n=56) mild, 20% (n=29) moderate and 4% (n=5) severe visual impairment.
17% (n=24) reported visual disturbances during dialysis, most commonly blurring of vision, or difficulty reading/watching TV. Of these 29% dropped a VA category across HD.
Looking at the VA categories for each eye; 59% remained unchanged, 17% improved and 25% (41% of patients) deteriorated (Wilcoxon p=0.06, no difference between pre and post VA categories). Patients with a decline in VA category were older, median age 74 years (IQR 16) vs 69 years (IQR 21), p=0.05 and more likely to require corrective visual aids (p=0.04) than patients without a decline in VA category.

Conclusions : This study illustrates that HD patients have a high prevalence of visual impairment, and a subgroup experience significant decline in VA in response to dialysis treatment. This may pose a significant risk in this vulnerable population who often experience high levels of comorbidity and physiological frailty. Further work is required to understand the mechanisms, associated factors and impact of this problem.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.