Corneal Hysteresis in Thais and Variation of Corneal Hysteresis in Glaucoma

Abstract

Purpose To collect the normal value data of corneal hysteresis in Thais and study the variation of corneal hysteresis in glaucomatous eyes. Methods Retrospective cross-sectional study of corneal hysteresis (CH) in healthy non-glaucomatous and glaucomatous eyes. Demographic data, type and staging of glaucoma, Goldmann applanation tonometry (GAT) and ocular response analyzer parameters; CH, corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) were collected. Results Data from one eye of 465 normal participants were included for the normal value data of CH. Mean CH, IOPcc and IOPg were 10.18 ± 1.48, 15.01 ± 3.04 and 14.16 ± 3.06 mmHg, respectively. Average age was 57.21 ± 14.4 years. CH at the fifth percentile was 8.0 mmHg. Women had significantly higher CH than men (10.29 ± 1.46 vs 9.90 ± 1.49 mmHg, p=0.009). Moderate negative correlation was found between age and CH, r = −0.338, p<0.001. There were 695 glaucomatous eyes from 429 patients including primary-open angle glaucoma (POAG), primary close-angle glaucoma (PACG), normal tension glaucoma (NTG) and ocular hypertension (OHT). CH in each glaucoma type and severity stage (early, moderate and severe) were as follows: POAG: 8.74 ± 1.52 mmHg (9.22 ± 1.47, 8.74 ± 1.23 and 7.92 ± 1.40 mmHg, p<0.001), PACG: 9.09 ± 1.72 mmHg (9.85 ± 1.45, 9.04 ± 1.68 and 8.45 ± 1.74 mmHg, p= 0.004), NTG: 9.55 ± 1.67 mmHg (9.47 ± 1.38, 9.75 ± 2.42 and 9.77 ± 1.34 mmHg, p 0.525) and OHT: 10.10 ± 1.40 mmHg. Conclusion Compared with normal value data of corneal hysteresis, CH in glaucomatous eyes was lower. The more advanced glaucoma stage was associated with lower CH. Arising from normal value data, a low percentile of CH could be applied as the deviation value from normal and this dynamic property of CH could represent a glaucoma predictor in an effort to improve glaucoma care.

Comparison of two analyzer measurements focusing on material stiffness among normal, treatment-naïve, and treated glaucoma eyes

“…The current study revealed comparative values (10.02 and 9.18 mmHg for control and treated POAG eyes, respectively). CH was significantly lower in the treated POAG group, as previously reported 9 , 50 . However, no significant difference was observed in CH between the control and treatment-naïve POAG groups, with the AUC value as low as 0.59.…”

“…Previous studies indicated that CH measured with ORA is useful when diagnosing 9 , monitoring the development 10 , and conducting management 12,13 of glaucoma. Many studies have reported CH in normative (9.77-10.20 mmHg) [49][50][51] and also treated glaucomatous eyes (7.5-9.5 mmHg) [12][13][14]35 . The current study revealed comparative values (10.02 and 9.18 mmHg for control and treated POAG eyes, respectively).…”

Corneal Biomechanical Measures for Glaucoma: A Clinical Approach

“…For example, the mean CH in the POAG-HTG severe stage was 7.92 mmHg compared to 9.22 mmHg in the early stage and 8.74 in the moderate stage (p < 0.001). In PACG, the mean CH was statistically significantly lower in the severe stage (8.45) compared to the early stage (9.85) (p = 0.004) but not when compared to the moderate stage (9.04, p = 0.2) [71]. In contrast, in a study of 49 patients, Yang and colleagues compared the CH in POAG-HTG versus POAG-NTG and reported no significant difference (10.11 mmHg versus 10.17 mmHg, respectively) (p = 0.81) [77].…”