Effect of Fasting on Intraocular Pressure (IOP) in Normal Individuals

BACKGROUND AND OBJECTIVE: Fluctuation of IOP in individuals can also be induced by the osmotic variations caused by water ingestion. In fasting, the individual ingests much water and other fluids in dawn and dusk that may lead to increased IOP and optic disorder. The aim of this study was to determine the effect of fasting on high fluctuation of IOP and optic disorder in healthy persons.METHODS: This analytical observational study was performed on 35 randomly selected healthy persons (70 eyes) at Shahid Beheshti hospital, Babol, Iran in the months of Ramadan and Zighadeh, 2007. IOP was measured with Goldman applanation tonometer, first in Ramadan month at 3 times: morning, afternoon and after dusk (breaking one’s fast) and then two months later (control month) in the morning and evening and then compared.FINDINGS: Average IOP in Ramadan month in the morning was14.4 mmHg, in the afternoon was 13.6 mmHg, and dusk (after breaking one’s fast) was 13.8 mmHg. Average IOP in control month in the morning was 13.4 mmHg and in the evening was 14 mmHg. There was a significant difference between Ramadan morning and control month morning (p=0.015). There was a significant difference between morning and afternoon of Ramadan (p=0.013). There was no significant difference between afternoon and dusk (after breaking one’s fast) in Ramadan.CONCLUSION: According to the results of this study, the rate of IOP between morning and afternoon in Ramadan and between Ramadan morning and control month morning was statistically significant. Since the increasing rate was not clinically valuable so the optic nerve can not be damaged