Twenty-Four-Hour Intraocular Pressure Pattern In Glaucoma Suspects in an African Population

Abstract

Précis: Twenty-four-hour intraocular pressure measurement (Phasing) among glaucoma suspects showed higher intraocular pressure (IOP), greater fluctuation, and more varying peak times occurring mostly outside clinic hours, between 12 midnight and 8 am in 68.9% of them. Purpose: To characterise 24-hour variation in IOP, in glaucoma suspects and normal individuals in an African population. Materials and Methods: A cross-sectional analytical study was carried out between March and October 2019 at the University of Ilorin Teaching Hospital. A total of 204 study participants, comprising 102 primary open angle glaucoma (POAG) suspects and 102 age and sex-matched controls with healthy eyes were recruited. Participants had a comprehensive ophthalmic examination. Measurements of IOP were taken every 2 hours during a 24-hour period using an iCare tonometer. Results: The mean age was 43.64±14.02 SD and 43.02±13.55 SD (P=1.000) for POAG suspects and controls, respectively. The mean peak IOP was significantly higher in POAG suspects (21.87± 4.65 mm Hg) compared with controls (17.17± 2.32 mm Hg) (P<0.001). Whereas, the mean trough IOP reading was not significantly different between the 2 groups. In both groups of participants, the peak and trough IOP in the majority were recorded outside of clinic hours. The majority (68.9%) of POAG suspects had a peak IOP between midnight and 8 am, whereas the control group peaked mostly at 4 pm (16.7%) and 4 am (41.7%). Twenty-four-hour IOP variation was 6 mm Hg or less in 73.6% of control eyes, while in the POAG suspects, 83.3% of eyes had variation greater than 6 mm Hg. Conclusions: Compared with age and sex-matched healthy controls, glaucoma suspects of African descent showed significantly higher mean IOP and IOP variation, with most peak IOP detected outside of clinic hours.