Effect of Reduced Meal Frequency during Ramadan Fasting on Retinal and Choroidal Thickness

Intermittent Fasting to the Eye: A New Dimension Involved in Physiological and Pathological Changes

Intermittent fasting (IF) is gaining popularity as a therapeutic dietary strategy that regulates metabolism and can alter the development of metabolic disorders. An increasing amount of research has connected ocular diseases to IF and discovered that it has a direct and indirect effect on the eye’s physiological structure and pathological alterations. This article summarizes the progress of research on IF in regulating the physiological structures of the ocular vasculature, the anterior segment of the eye, the retina, and the choroid. We explored the therapeutic potential of IF for various common ocular diseases. In the future, a comprehensive study into the fundamental processes of IF will provide a direct and rigorous approach to eye disease prevention and therapy.

Effect of fasting on diurnal fluctuation of parafoveal and peripapillary vessel density and related oculodynamic and haemodynamic parameters

PURPOSE

To investigate the effects of Ramadan fasting on diurnal superficial-deep parafoveal vessel density (pfVD) and nerve head (NH)-radial peripapillary capillary (RPC) peripapillary vessel density (ppVD) using optical coherence tomography angiography (OCTA), as well as other related oculodynamic and haemodynamic parameters, and to compare these findings with those in the nonfasting period in healthy individuals.

METHODS

A total of 105 healthy individuals, 42 women and 63 men, were included in this prospective study. OCTA was used to examine the superficial-deep pfVD and NH-RPC ppVD. In the third week of Ramadan, OCTA readings were obtained twice daily at 08:00 and 16:00 hour (h) under fasting conditions and compared with nonfasting values 2 weeks after Ramadan. Both intraocular pressure (IOP) and blood pressure values were assessed accordingly.

RESULTS

The mean age (23-51) of individuals was 34.37 ± 7.04 years. In comparison with the 08:00 -h values, the 16:00 -h IOPs, superficial-deep pfVDs and RPC ppVDs were substantially reduced both during the fasting and nonfasting periods (P = 0.001, P = 0.009, P = 0.006, P = 0.006, P = 0.004, P = 0.004, P = 0.41, P = 0.032 and P = 0.021). No differences were found in the diurnal change of superficial-deep pfVDs, NH-RPC ppVDs, IOPs and mean ocular perfusion pressures (MOPPs) between the fasting and nonfasting periods, whereas the same was not true for mean arterial blood pressures (MABPs) (P = 0.049).

CONCLUSIONS

The parafoveal and peripapillary VDs (except for NHpp-VD) and IOPs were found to have decreased significantly throughout the day both in fasting and nonfasting periods. Our study confirms the diurnal changes in the IOPs, MOPPs, superficial-deep pfVDs and NH-RPC ppVDs under dehydration and normal terms.

The effect of religious fasting and dehydration at Ramadan on choroidal thickness and Retinal vessel densities, measured with optical coherence tomography angiography

AIM

To investigate the effect of religious fasting and dehydration at Ramadan on choroidal thickness and vessel density in the superficial and deep vascular plexuses with OCTA.

METHODS

The choroidal thickness, and superficial and deep vessel density indices of fasting healthy subjects were measured with an OCTA device, and compared with non-fasting measurements.

RESULTS

The study included 70 eyes of 35 healthy subjects with a mean age of 42.86 ± 8.3 years. The measured choroidal thickness, superficial vessel density index and deep vessel density index were 288.89 ± 67 µm, 40.56% and 41.43%, respectively when measured in the fasting period, compared to 284.62 ± 65 µm, 40.41% and 41.41%, respectively when measured in the non-fasting period. The choroidal thickness under the fovea center was found to be significantly higher in the fasting period than in the non-fasting period (p = 0.014). The mean total choroidal thickness was found to be reduced in the non-fasting period, although not to a statistically significant degree (p > 0.05). An analysis of the mean total superficial and deep vascular plexuses revealed no statistically significant difference (p = 0.368, p = 0.938 respectively).

CONCLUSION

Although a significant increase was noted in central choroidal thickness in the fasting period, no significant change due to fasting was observed in the superficial and deep capillary plexuses. The choroidal layer may vary in thickness due to fasting-related metabolic factors, while retinal vessels are more stable against such effects.

Effect of reduced meal frequency during Ramadan fasting on retinal and choroidal thickness

This paper is a comment on the article entitled "Effect of reduced meal frequency during Ramadan fasting on retinal and choroidal thickness'' by Ersan et al. We think this paper will make a significant contribution to this article and to the literature.

Quantitative assessment of the effect of fasting on macular microcirculation: an optical coherence tomography angiography study

Aim

To analyse the effect of fasting on the retinal vascular plexus and choriocapillaris structures in healthy subjects via Optical Coherence Tomography Angiography (OCTA).

Methods

In this prospective study, OCTA scans of 98 eyes in 49 healthy subjects were compared in fasting and non-fasting period. All cases had a full ophthalmological examination, with OCTA parameters measured, including superficial flow area (SCP) (mm2), deep flow area (DCP) (mm2), choriocapillaris flow area (CC) (mm2), superficial and deep vascular density (SVD and DVD, respectively) (%), superficial foveal avascular zone area (FAZs) (mm2), deep foveal avascular zone area (FAZd) (mm2), subfoveal choroidal thickness (SFCT) (µm) and central macular thickness (CMT) (µm).

Results

The mean SCP, DCP and CC flow area values were induced to be significantly lower in a fasting than a non-fasting period (p<0.001, p<0.001, p=0.049, respectively). The mean VD in a fasting period was statistically significantly lower than in a non-fasting period at the SCP level (p=0.009). No statistically significant difference was found between the two periods in respect to DVD, FAZd and CMT (p=0.068, p=0.653 and p=0.531, respectively); however, FAZs were significantly lower in a non-fasting than fasting period (p=0.038). The SFCT was determined to be statistically significant and thicker during a fasting period (p<0.001).

Conclusion

The current study documented several physiological changes in a fasting period, such as changes in SCP, DCP, CC flow, SVD and DVD, via OCTA.