Comparing 24-hour IOP fluctuation slope curve between newly diagnosed ocular hypertension and primary open-angle glaucoma

Qing Zhang; Hui Feng; Ye Zhang; Dong Han; Guangxian Tang; Su Jie Fan; Hengli Zhang; Jing Jiang; Aiguo Lv; Shuning Li

doi:10.1136/bmjophth-2024-001821

Comparing 24-hour IOP fluctuation slope curve between newly diagnosed ocular hypertension and primary open-angle glaucoma

BMJ Open Ophthalmol. 2024 Sep 23;9(1):e001821. doi: 10.1136/bmjophth-2024-001821.

Authors

Qing Zhang^#^{1

2}, Hui Feng^#¹, Ye Zhang¹, Dong Han³, Guangxian Tang⁴, Su Jie Fan⁵, Hengli Zhang⁴, Jing Jiang⁶, Aiguo Lv⁵, Shuning Li⁷

Affiliations

¹ Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Science Key Lab, Capital Medical University, Beijing, China.
² Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
³ Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei, China.
⁴ Department of Ophthalmology, 1st Hospital of Shijiazhuang, Shijiazhuang, Hebei, China.
⁵ Department of Ophthalmology, Handan 3rd Hospital, Handan, Hebei, China.
⁶ Department of Glaucoma, Fushun Eye Hospital, Fushun, Liaoning, China.
⁷ Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Science Key Lab, Capital Medical University, Beijing, China lishuningqd@163.com.

^# Contributed equally.

Abstract

Objective: To compare the 24-hour intraocular pressure (IOP) fluctuation slope curve between newly diagnosed patients with ocular hypertension (OHT) and primary open-angle glaucoma (POAG).

Methods and analysis: Newly diagnosed and untreated OHT and POAG patients who underwent 24-hour IOP monitoring were consecutively enrolled in the study. IOP measurements were taken every 2 hours from 8:00 to 6:00 hours the following day using an iCare PRO tonometer. Patients maintained their daily routines, with IOP measured in a seated position during the day and supine at night. The 24-hour IOP fluctuation indices, including peak, trough and overall fluctuation, were calculated. Differences in the 24-hour IOP fluctuation slope curves over time between groups were analysed using a generalised additive mixed model.

Results: 46 patients with OHT and 41 with POAG were included. From 2:00 to 10:00 hours, mean IOP increased by 0.69 mm Hg every 2 hours in the POAG group (p<0.0001) and by 0.40 mm Hg in the OHT group (p<0.0001). After 10:00, the IOP showed a downward trend, decreasing by 0.31 mm Hg in the POAG group (p<0.0001) and by 0.17 mm Hg in the OHT group (p=0.0003) every 2 hours. The rate of slope change in the upward phase differed significantly between the groups (0.30 mm Hg per 2 hours; p=0.02), as did the rate in the downward phase (0.14 mm Hg per 2 hours; p for interaction=0.04). Multivariate models showed that each 1 mm Hg increase in circadian and diurnal IOP fluctuation was associated with a 27% and 21% higher likelihood of POAG presence, respectively.

Conclusion: The 24-hour IOP slope curve differed between POAG and OHT, with a steeper slope observed in the POAG group. However, the study is limited by potential confounding factors, reliance on a single 24-hour measurement period and the need for further longitudinal studies to validate these findings.

Keywords: Glaucoma; Intraocular pressure; Ocular Hypertension.

Publication types

Comparative Study

MeSH terms

Adult
Aged
Circadian Rhythm* / physiology
Female
Glaucoma, Open-Angle* / diagnosis
Glaucoma, Open-Angle* / physiopathology
Humans
Intraocular Pressure* / physiology
Male
Middle Aged
Ocular Hypertension* / diagnosis
Ocular Hypertension* / physiopathology
Tonometry, Ocular* / methods