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Abstract #104959 Published in IGR 23-2
Diurnal Variation of Corneal Hysteresis in Patients with Untreated Primary Open-angle Glaucoma and Normal Individuals
Okayama M; Tsuchiya S; Higashide T; Udagawa S; Yamashita Y; Shioya S; Takemori H; Nakazawa K; Manbo Y; Manbo Y; Sugiyama KJournal of Glaucoma 2022; 31: 891-897
PRECIS: Corneal hysteresis in both patients with untreated open-angle glaucoma and normal individuals demonstrated significant diurnal variation independent of confounding factors, and was higher in the nighttime than in the daytime. PURPOSE: To investigate diurnal variations in corneal hysteresis (CH) in patients with untreated primary open-angle glaucoma (POAG) and normal individuals by using an ocular response analyzer (ORA). METHODS: This prospective study included 72 eyes of 53 patients with untreated POAG and 53 eyes of 47 normal individuals. Intraocular pressure (IOP) and CH were measured using Goldmann applanation tonometry (GAT) and ORA, respectively, every 3 h from 9:00 to 24:00. Mixed-effects models were used to determine factors associated with CH values and CH amplitude (maximum-minimum values) and to examine the diurnal variations in GAT IOP and CH in each group. Significant differences between time points were defined as significant variations. RESULTS: The diurnal average GAT IOP and CH in patients with POAG were significantly higher and lower than those in normal individuals (P=0.001, 0.002). In the multivariate analysis, larger central corneal thickness was associated with larger CH values in POAG and normal eyes (both P<0.001). A larger amplitude of GAT IOP was significantly associated with a larger CH amplitude in POAG and normal eyes (P=0.010, 0.013). CH in both groups showed similar significant diurnal variation, and was higher in the nighttime than in the daytime, even after adjusting for confounding factors, while IOP showed an antiphase pattern. CONCLUSION: CH in both untreated POAG patients and normal participants demonstrated similar diurnal variations, i.e., higher at night, independent of confounding factors. These findings suggest that viscoelastic properties of the cornea may fluctuate diurnally independent of IOP.
Department of Ophthalmology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa 920-8641, Japan.
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