Abstract
Purpose: :
To evaluate systemic and ocular hemodynamic risk factors for glaucomatous damage in eyes with normal-tension glaucoma (NTG)
Methods: :
A total of 693 consecutive patients with NTG underwent 24-hour monitoring of intraocular pressure (IOP) and blood pressure (BP), Heidelberg retinal tomographII (HRTII), Color Doppler imaging (CDI), and Humphrey visual field examination (VF). Multivariate regression analysis was used to detect risk factors for both functional and morphological glaucoma damage from various clinical variables including age, mean / peak / fluctuation of circadian IOP, central corneal thickness (CCT), average mean arterial pressure (MAP), circadian MAP fluctuation, average mean ocular perfusion pressure (MOPP), circadian minimum MOPP, resistance indexes (RI) of central retinal artery (CRA) and ophthalmic artery (OA) measured by CDI. Variables for functional glaucoma damage were mean deviation (MD) and corrected pattern standard deviation (CPSD). Variables for morphological glaucoma damage were parameters on HRTII.
Results: :
One hundred fourteen eyes of 114 NTG patients (53 men and 61 women) with ( mean age±SD: 54.2±12.3 years) met the inclusion criterion; refractive error <-6 diopter, best corrected visual acuity greater than 20/30, maximum IOP < 22 mmHg on multiple measurements, no history of a massive hemorrhage or hemodynamic crisis, no history of diabetes mellitus or hypertension, without use of antiglaucoma medications, without use of anti-hypertension or hemodynamically active medications. In the multivariate regression analysis, higher RI of CRA was significantly associated with decreased MD (p=.04) and increased CPSD (p<.01) of functional outcome variables and with decreased rim volume (p<.01) and increased C/D ratio (p<.01) among morphological outcome variables. Larger circadian fluctuation of IOP (p=.02) and older age (p<.01) were significantly associated with decreased MD. Lower circadian minimum MOPP (p=.05) was significantly associated with decreased mean RNFL thickness among morphological outcome variables.
Conclusions: :
Of the functional and morphological outcome variables, higher RI of CRA was the most consistent risk factor for glaucoma damage in eyes with NTG. Circadian minimum MOPP, circadian fluctuation of IOP, and age were also associated with severity of glaucoma damage.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • blood supply