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.
Keywords: Diurnal fluctuation of retinal vessel density; Fasting; OCTA; Parafoveal; Peripapillary.
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