The Effects of Hemodialysis on Tear Osmolarity

Analytical Study of Ocular Surface Changes in Patients of Chronic Kidney Disease undergoing Hemodialysis and Peritoneal Dialysis

Objectives The idiopathic group is a significant cause of chronic kidney disease (CKD) in developing countries. Literature available on ocular surface changes has predominantly been reported in patients undergoing hemodialysis. Little is known about the changes in patients undergoing peritoneal dialysis. The present study aimed to identify ocular surface changes in an idiopathic group of CKD undergoing dialysis.

Aim To compare tear film disorders and the severity of ocular surface changes (goblet cell density, squamous metaplasia, and corneoconjunctival calcification) in patients of idiopathic etiology with CKD undergoing hemodialysis and peritoneal dialysis. This is an analytical study.

Materials and Methods Asymptomatic adult patients of idiopathic CKD, on treatment with dialysis underwent comprehensive ophthalmic examination, including best-corrected visual acuity, slit-lamp examination, and a dilated fundus examination. Dry eye assessment was done by ocular surface staining score, Schirmer test, and tear breakup time (TBUT). Conjunctival impression cytology was studied to assess changes on ocular surface. Chest X-rays for aortic calcification were reviewed and data analyzed.

Results Both eyes of 76 patients of hemodialysis and 32 patients of peritoneal dialysis were studied. Ocular surface staining (OSS) scores were low. Impression cytology showed a drop in goblet cell density, presence of squamous metaplasia, and conjunctival keratinization significantly more in the hemodialysis group. No correlation was seen between the presence of conjunctival calcification and aortic calcification.

Conclusion The hemodialysis group had mild subclinical dry eye but keratinization of conjunctiva was seen. Similarly, advanced squamous metaplasia was seen in the peritoneal dialysis group. These changes were positively correlated to decrease in goblet cell density.

Tear function in patients with diabetes mellitus: A systematic review and meta-analysis

PURPOSE

To examine tear function in patients with diabetes mellitus (DM).

DESIGN

Systematic review and meta-analysis.

METHOD

We searched Embase and PubMed from database inception to March 16, 2022. We included observational studies that compared tear function between patients with and without DM. Tear function was measured using invasive tear breakup time (ITBUT) and Schirmer's 1 test. Pooled results are presented as standard mean difference (SMD) with 95% confidence interval (CI) based on random-effects models.

RESULTS

We included 59 studies (7,234 eyes) comparing the tear function between patients with and without DM. This meta-analysis indicated that patients with DM had worse tear function than those without DM (ITBUT: SMD: -0.98, 95% CI: -1.27 to -0.69; Schirmer's 1 test: SMD: -0.45, 95% CI: -0.64 to -0.26), and the results remained consistent in patients with different types of DM (e.g., type 1 DM and type 2 DM) and from different ethnic backgrounds (e.g., Asian vs. non-Asian). Patients with DM under poor glycemic control had worse tear function than those of the non-DM group (ITBUT: SMD: -1.26, 95% CI: -1.86 to -0.66; Schirmer's 1 test: SMD: -0.25, 95% CI: -0.48 to -0.02), whereas there were no significant differences in tear function between patients with DM under optimal glycemic control and non-DM groups.

CONCLUSIONS

We found that patients with type 1 or type 2 DM had significantly reduced tear function. The level of tear function could be determined by glycemic control, and therefore, our findings suggest that glycemic control in patients with DM is critical for maintaining tear function.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero, identifier CRD42021250498.

Tear dynamics testing and quantitative proteomics analysis in patients with chronic renal failure

Ocular surface changes may develop in patients with chronic renal failure (CRF) undergoing hemodialysis. In recent years, an association of CRF with dry eye syndrome has been emphasized. However, tear proteomics of CRF patients has not been analyzed. Here, we performed systematic profiling of the tear film proteins in CRF patients through use of isobaric tags for relative and absolute quantitative (iTRAQ) MS/MS, aiming to identify associations between dry eye symptoms and expression of tear proteomic changes in patients with CRF undergoing hemodialysis. Twenty CRF patients and ten healthy subjects underwent a series of ophthalmic examinations. Tear samples from the participants were analyzed by iTRAQ approach. A total of 1139 tear proteins were screened, and 212 differentially expressed proteins were identified. The pattern changes included 77 whose expression levels were upregulated (fold increase >1.2) whereas 135 others that were downregulated (fold decrease <1/1.2). Bioinformatics analysis showed that these proteins were significantly enriched in lipid metabolism, inflammatory, and immune response pathways. Furthermore, APOA1, APOA4, APOB, APOE, S100A8, S100A9, S100A4, HSP90B and other molecules were significantly changed. Our study elucidated the characteristics of tear dynamics and protein markers in CRF patients undergoing hemodialysis. Significance: Despite the association of chronic renal failure (CRF) with dry eye disease, there are no reports describing potentially important differentially expressed tear proteins in CRF patients undergoing hemodialysis. It is still a challenge to obtain a comprehensive description of the pathogenesis of dry eye in CRF patients which hinders establishing a patient specific therapeutic scheme. Our study is the first iTRAQ proteomics analysis of the tears of patients with CRF, which reveals the changes in the protein expression profile in CRF patients afflicted with dry eye disease. The identity was verified of some relevant differentially expressed proteins, and they may be candidate diagnostic markers of dry eye disease in patients with CRF. These tear film protein constituents found in hemodialysis patients can be of important clinical significance in treating this condition. SIGNIFICANCE: Despite the association of chronic renal failure (CRF) with dry eye disease, there are no reports describing potentially important differentially expressed tear proteins in CRF patients undergoing hemodialysis. It is still a challenge to obtain a comprehensive description of the pathogenesis of dry eye in CRF patients which hinders establishing a patient specific therapeutic scheme. Our study is the first iTRAQ proteomics analysis of the tears of patients with CRF, which reveals the changes in the protein expression profile in CRF patients afflicted with dry eye disease. The identity was verified of some relevant differentially expressed proteins, and they may be candidate diagnostic markers of dry eye disease in patients with CRF. These tear film protein constituents found in hemodialysis patients can be of important clinical significance in treating this condition.