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Biomechanical properties of eyes with asymmetrical glaucoma defect
Author(s) -
Cellini M.,
Gizzi C.,
Finzi A.,
Campos E.C.
Publication year - 2015
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2015.1296
Subject(s) - glaucoma , ophthalmology , medicine , visual field , open angle glaucoma , optic nerve
Purpose To evaluate biomechanical properties in eyes of patients affected by primary open angle glaucoma ( POAG ) with marked asymmetrical defects by means of Ocular Response Analyzer ( ORA ) and Spectral Domain OCT with Enhanced Depth Imaging ( EDI SD ‐ OCT ) function. Methods We studied 20 patients (mean age: 56 ± 12) with asymmetrical POAG . One eye was classified as mild glaucoma ( MG ) and the sound eye as severe glaucoma ( SG ) by visual field indexes: MD −4.21 ± 1.51 vs −16.56 ± 5.76 dB; p = 0.011 and PSD 3.54 ± 0.87 vs 10.95 ± 3.51 dB; p = 0.007. An EDI SD ‐ OCT centered on the optic nerve head and an ORA examination were performed on each eye of every subject before and during a IOP increase of 12.5 ± 2.1 mm/Hg induced by a compression of the globe with an ophthalmodinamometer. Corneal histeresis ( CH ), corneal resistence factor ( CRF ) and laminar displacement ( LD ) were statistically analyzed by Wilcoxon's rank sum test and Spearman's correlation test considering significant a p < 0.05. Results After IOP increase we found a decrease of CH : 9.3 ± 3.66 vs 6.92 ± 3.04 mm/Hg; p = 0.012 in SG and 8.62 ± 2.16 vs 7.23 ± 2.29 mm/Hg; p = 0.176 in MG . CRF instead increase: 8.61 ± 2.31 vs 12.38 ± 3.65 mm/Hg; p = 0.016 in SG and 9.02 ± 1.48 vs 12.22 ± 5.68 mm/Hg; p = 0.041 in MG . LD was positive in MD : 29.08 ± 19.28 μm and negative in AG ‐ 6.58 ± 16.09 μm. In AG eyes we found a correlation between LD and CRF (r = −0.658; p = 0.019) and between LD and Scleral Rigidity (r = −0.693; p = 0.012). Conclusions This study demonstrates that in asymmetrical glaucoma the IOP increase changes the eye biomechanics with stiffening of the eye structures that involves not only the lamina cribrosa but also the corneal tissue.