Evaluation of changes in tear film parameters in patients with advanced and end-stage chronic kidney disease

Aim
The dry eye syndrome is a common reason for medical appointments. Many factors, including local and systemic disorders or drugs contribute to its occurrence. The aim of the study was to assess changes on the ocular surface in patients with advanced (G4) and end-stage (G5) chronic kidney disease.

Material and methods
Depending on the estimated glomerular filtration rate (eGFR) and the treatment used, the subjects were divided into three groups. Group I: patients with end-stage chronic kidney disease on haemodialysis (chronic kidney disease stage 5); Group II: patients with markedly decreased eGFR (chronic kidney disease, stage 4); Group III: people with normal eGFR. Tear film break-up time test and Schirmer II test were performed. Conjunctival hyperaemia, conjunctival/ corneal calcifications as well as fluorescein and lissamine green staining were assessed.

Results
There were no differences in the prevalence of conjunctival hyperaemia (p = .147), bulbar conjunctival calcifications (p = .484) and corneal calcifications (p = .687). The study groups differed significantly with regards to the prevalence of pingueculae in the bulbar conjunctiva (p = .024), Schirmer II test and tear film break-up time. Corneal staining with fluorescein and lissamine green showed no differences between the study groups (p = .433 and p = .140, respectively). Both staining methods yielded significant differences with regards to the surface of the bulbar conjunctiva (p = .002 and p = .0001, respectively).

Conclusions
Advanced chronic kidney disease and haemodialysis negatively affect the tear film. Conjunctival abnormalities appear to be associated with degenerative processes which occur more frequently in patients with chronic kidney disease. There was no difference in the condition of ocular surface and tear film parameters between patients with G4 and G5 of chronic kidney disease.