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The effect of hemodialysis on intraocular pressure (IOP) has not been well-studied and remains controversial. Studies have found both an increase as well as decrease of IOP during hemodialysis. The low sampling rate of current tonometry techniques and the resultant high variability of IOP data are likely contributors to this confusion.
Panagiotou et al. investigated 24-h IOP characteristics of 18 non-glaucomatous subjects before and during hemodialysis. They obtained seven daily measurements (including two during the nocturnal period) using applanation tonometry in the habitual body positions. They found statistically significantly higher mean IOP (+1.3 mmHg), peak IOP, and IOP fluctuations on the day of hemodialysis compared to treatment-free day. These differences, however, were explained by a single time-point IOP difference (at 17.00, peak IOP) between the two treatment days. Overall, the IOP patterns were similar. Is that difference of any clinical relevance?
At present, it is unknown whether patients undergoing hemodialysis are at higher risk of glaucoma
Important limitations are the small sample size and the dependency of the significance of IOP findings on a single time-point IOP. In fact, although the time of peak IOP on treatment day corresponded with the end of the hemodialysis treatment, peak IOP also occurred at the same timepoint on the non-treatment day. This is surprising since studies show circadian IOP to be usually at its lowest in the late afternoon. It can be speculated that non-physiological (e.g., hemodialysis) or study-related factors may have contributed to this finding. The authors, however, did not find a correlation between IOP change and the duration of hemodialysis.
At present, it is unknown whether patients undergoing hemodialysis are at higher risk of glaucoma. Despite major shortcomings, this study has highlighted an interesting area of research.