|Year : 2020 | Volume
| Issue : 3 | Page : 77-82
Effect of fasting on intraocular pressure in glaucomatous patients
Walid Abdelghaffar, Marwa Abdelshafy, Mohamed N Elmohamady
Deparetement of Ophthalmology, Benha Faculty of Medicine, Benha University, Benha, Egypt
|Date of Submission||07-Mar-2020|
|Date of Acceptance||24-Jun-2020|
|Date of Web Publication||07-Sep-2020|
MD Marwa Abdelshafy
1 El Amira Fawzya Street, El Vilal, Banha, El Qalubyai, 13512
Source of Support: None, Conflict of Interest: None
Purpose The aim of this study was to assess the effect of intermittent fasting and dehydration on intraocular pressure (IOP) in patients under glaucoma treatment.
Patients and methods The present study was conducted on 36 glaucoma cases and 30 healthy controls of matched age and sex. IOP measurements with Goldmann applanation tonometer were taken 1 week before fasting (at 8.00 a.m.), during Ramadan fasting (first, second, third, and fourth week) (at 8.00 a.m. and 4.00 p.m.), and 1 week after Ramadan during the nonfasting period (at 8.00 a.m.).
Results The study was conducted on 36 glaucoma cases; their mean age was 47.3 years. There were 12 (33.3%) men and 24 (66.7%) women and 30 healthy participants, their mean age was 47.7 years. There were 11 (36.7%) men and 19 (63.3%) women. There was gradual decrease in IOP with fasting, in both glaucomatous cases and control groups, with no significant differences in IOP between groups during fasting. Glaucoma cases showed significantly higher percentage change in IOP (either improvement or deterioration) when compared with the control group.
Conclusion Our results showed that fasting during Ramadan has a lowering effect on IOP values in healthy controls and glaucomatous patients. Glaucoma cases showed significantly higher percentage change in IOP when compared with the control group.
Keywords: dehydration, fasting, glaucoma, intraocular pressure
|How to cite this article:|
Abdelghaffar W, Abdelshafy M, Elmohamady MN. Effect of fasting on intraocular pressure in glaucomatous patients. J Egypt Ophthalmol Soc 2020;113:77-82
|How to cite this URL:|
Abdelghaffar W, Abdelshafy M, Elmohamady MN. Effect of fasting on intraocular pressure in glaucomatous patients. J Egypt Ophthalmol Soc [serial online] 2020 [cited 2021 Apr 12];113:77-82. Available from: http://www.jeos.eg.net/text.asp?2020/113/3/77/294442
| Introduction|| |
Fasting is observed every year by Muslims worldwide . During this month Muslims have to fast from dawn until sunset; food and drinks are not allowed. Mean fasting duration may vary from 13 to 18 h . The intermittent fasting has multiple effects on the metabolism of different body systems. Many investigators had considering the possibility of occurrence of various health problems or exacerbation of present disorders .
Normal intraocular pressure (IOP) ranges from 10 to 20 mmHg, with diurnal fluctuations of 2.75 mmHg. IOP increases in the morning and decreases in the evening; this fluctuation may be due to different serum cortisol concentrations . IOP is a very important factor in the evaluation of the participants at risk of glaucoma. Any changes in the renin–angiotensin system and the levels of carbonic anhydrase or serum electrolytes can affect IOP ,,. Inadequate water intake and dehydration can significantly affect the lipid profile , serum electrolytes, for example, potassium, sodium, bicarbonate, chloride, albumin, hematocrit, urea, creatinine, urinary osmolality, melatonin , and cortisol levels, which have a striking effect on ocular blood flow and IOP ,.
Few previous researchers studied the impact of dehydration and fasting on various physiological parameters of the ocular system . Due to the limited scientific researches previously studied the influence of fasting on different eye issues and medications, as well as the importance of regional investigations due to discrepancies in the mean fasting duration and nutritional habits, we conducted this study to evaluate the possible changes in the IOP during Ramadan in glaucomatous patients.
| Patients and methods|| |
This study included 36 patients with primary open angle glaucoma and 30 healthy participants of matched age and sex as the control group. This prospective cross-sectional comparative study was done between May 2019 and June 2019. Participants with a past history of ocular surgery were excluded. The participants were recruited from the outpatients’ clinics of Benha University Hospital. After approval of the University Ethics Committee, an informed written consent in Arabic was signed by all participants and was in compliance with the requirements of the Declaration of Helsinki and its updates.
All participants had fasted whole days of the Ramadan and all had took the predawn meal and drink. All glaucomatous patients were on antiglaucomatous drops and they continued the same drops all through the month.
Demographic data were collected from all participants. After performing refraction measurements, all participants were tested for best-corrected visual acuity using the Snellen chart. All participants were submitted to slit-lamp biomicroscopy and dilated fundus examination. IOP was measured via Goldmann applanation tonometry (Haag-Streit, Mason, Ohio, USA). IOP measurements were taken 1 week before Ramadan (at 8.00 a.m.), during Ramadan fasting (first, second, third, fourth week). (; at 8.00 a.m., about 3 h after the predawn meal) (at 4.00 p.m. 3.5 to 4 h before sunset), and 1 week after Ramadan during the nonfasting period (at 8.00 a.m.).
The data were introduced to a PC using the Statistical Package for the Social Sciences (Released 2017. IBM SPSS Statistics for Windows, Version 25.0; IBM Corp., Armonk, New York, USA). Data were presented, and suitable analysis was done according to the type of data obtained for each parameter. Shapiro–Wilk test was done to test the normality of data distribution. Significant data was considered to be nonparametric. Mean − and SD was used for parametric data, while median and range were used for nonparametric data. Student’s t-test was used to assess the difference between the two groups. Mann–Whitney test (U test) was used to assess the difference of nonparametric variables. χ2 test was used to examine the relationship between two qualitative variables. Paired sample t test (for parametric) or Wilcoxon signed-rank sum test (for nonparametric) was used to assess changes in parameters over time. Correlation analysis: to assess the strength of association between two quantitative variables. Regression analysis: linear regression analysis was used for the prediction of risk factors, using generalized linear models. All tests were two-sided and a P value less than 0.05 was considered statistically significant.
| Results|| |
The study was conducted on 36 glaucoma cases; their mean age was 47.3 years. There were 12men (33.3%) and 24 (66.7%) women, in addition to 30 healthy controls of matched age and sex.
At 1 week before fasting, glaucoma cases showed significantly higher IOP when compared with the control group. There was gradual decrease in IOP with fasting, in both cases and control groups, with no significant differences in IOP between groups during fasting, while 1 week after fasting, IOP was significantly higher in cases when compared with control groups ([Table 1], [Figure 1]).
|Table 1 Comparison of intraocular pressure between cases and control groups|
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|Figure 1 Intraocular pressure over time in glaucoma cases and control groups.|
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In the control group, IOP decreased significantly at the first week after fasting when compared with before fasting; then it was stationary till the third week, at which it decreased significantly when compared with the second week; then it was stationary from the third to the fourth week of fasting. While after fasting, it increased significantly when compared with the fourth week of fasting. In glaucoma cases, IOP decreased significantly at first week after fasting when compared with before fasting; and in the second when compared with the first week; then it showed a nonsignificant decrease through the second, third, and fourth weeks. By 1 week after fasting, IOP increased significantly when compared with the fourth week ([Table 2]).
Percentage change in IOP was calculated over time. Glaucoma cases showed significantly higher percentage change in IOP (either improvement or deterioration) when compared with the control group ([Table 3], [Figure 2]).
|Table 3 Comparison of percentage change in intraocular pressure between cases and control groups|
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|Figure 2 Percentage change in intraocular pressure between cases and control groups.|
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No significant correlation was found between IOP over time with age in cases and control groups ([Table 4]).
|Table 4 Correlation between intraocular pressure over time with age in cases and control groups|
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Linear regression analysis was conducted for the prediction of change of IOP using age, sex, and fasting as confounders. Fasting was the only predictor for IOP improvement in all studied participants ([Table 5]).
|Table 5 Regression analysis for the prediction of change in intraocular pressure|
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| Discussion|| |
Fasting and dehydration have a significant impact on many physiological conditions that in turn affect various body organs including the eye ,.
Change in corneal hydration results in variability of the corneal fibril spacing, decreasing the stromal collagen lamellae organization, and lowering the corneal biomechanics. Any significant changes in corneal biomechanics may influence IOP measurements ,.
Previous studies have evaluated the effect of fasting and dehydration on IOP measurements and have reported inconsistent results. Some studies reported minimal effects of fasting in IOP ,,,,. Other studies reported significant decreased IOP values during fasting ,.
In this study, there was gradual decrease in IOP with fasting, in both cases and control groups, with no significant differences in IOP between groups during fasting., while 1 week after fasting, IOP was significantly higher in cases when compared with control groups.
Kayikçioglu and Güler  studied the effect of fasting and dehydration on IOP and stated no significant differences in IOP measurements of healthy participants in fasting and nonfasting conditions during different times of the day. Inan et al.  have also concluded nonsignificant differences in IOP measurements during fasting (12.71±2.25 mmHg) and nonfasting (13.14±2.62 mmHg) periods in healthy volunteers.
Soleymani et al.  compared IOP measurements in healthy participants during the fasting and nonfasting periods and reported a significant difference (P=0.015). They also concluded that fasting individuals had a more reduced IOP in the afternoon (13.6 mmHg) than in the early morning (14.4 mmHg) (P=0.013).
Rabbanikhah et al.  have noted a 1.1 and 1.5 mmHg decrease in IOP measurements comparing the results of the fourth and second week of fasting in normal participants. They also reported a significant increase of mean IOP 1 month after fasting. In another study they have also reported a 0.5 mmHg reduction in IOP measurements in the third week (at 5 p.m.) of Ramadan compared with that of 1 week before Ramadan (at 8:00 a.m.) .
All of the above-mentioned researches had studied the effect of fasting on IOP in healthy volunteers, whereas the study of its effects on IOP in glaucomatous patients is more critical to be assessed. In our study, there was statistically significant difference in IOP measurements values between fasting and nonfasting periods in glaucomatous patients. Our findings agree with the study by Salehi et al. , who also reported reduced IOP measurements during fasting periods in open-angle glaucoma patients.
In our study, IOP decreased significantly in glaucoma cases at first week after fasting when compared with before fasting and in the second when compared with the first week; then it showed a nonsignificant decrease through the second, third, and fourth weeks. By 1 week after fasting, IOP increased significantly when compared with the fourth week. Glaucoma cases showed a significantly higher percentage change in IOP (either improvement or deterioration) when compared with the control group.We conducted this study in May/June, which are warm summer months in our country; the reduction of IOP level may be postulated due to inadequate water intake during fasting in comparison with nonfasting periods. The reduction in water intake may result in increased plasma osmolality and reduced aqueous humor formation and also hunger and variable lipid profile effect prostaglandin secretion . Moreover, dehydration and hunger stimulate the sympathetic system with change in cortisol, melatonin, and epinephrine levels, which are demonstrated to influence IOP .
Our study was limited by the relatively small number of participants; this was because it is a single-center study. Another limitation is that the type of antiglaucomatous drugs was not considered, as some drugs decrease the aqueous formation and others increase aqueous outflow. We think that fasting may decrease aqueous formation but has no effect of aqueous outflow. We recommend future researches to study the effect of fasting on the IOP-lowering effect of different categories of antiglaucoma eye drops.
| Conclusion|| |
In conclusion, Ramadan fasting has a lowering effect on IOP measurements both in healthy participants and glaucomatous patients. Glaucoma cases showed significantly higher percentage change in IOP when compared with the control group.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]