The relationship between pulsatile ocular blood flow and glaucoma progression

Purpose: To investigate the relationship between pulsatile ocular blood flow (POBF) and glaucoma progressionMaterial and Method: Totally 234 eyes of 117 patients with primary open-angle glaucoma (POAG), ocular hypertension (OHT), normotensive glaucoma (NTG) and healthy volunteers between the ages of 19-77 have enrolled in this prospective study. Participants have been followed between the years 2008-2010 in the Karadeniz Technical University, Faculty of Medicine, Department of Ophthalmology. Intraocular pressure (IOP) measurements and visual field (VF) analysis were done at baseline, 3rd, 6th and 9th months. Mean Deviation (MD) and Pattern Standart Deviation (PSD) values were documented. Peripapillary nerve fiber layer analysis (RNFL) was done at each visit with Stratus optical coherence tomography. Maximum intraocular pressure (max. IOP), minimum intraocular pressure (min. IOP), mean intraocular pressure (mean IOP), POBF, maximum net inflow (MNI), pulsatility equivalence index (PEQ), inflow duration ratio (IDR) were measured at baseline, 3rd month, 6th month and 9th month using ocular blood flow device (Paradigm Medical, Utah, USA) and the differences were compared statistically.Results: The mean age of participants was 46.98±14.78 (19-77) in which 73 (%62.4) were female and 44 (37.6 %) were male. The mean IOP values measured at baseline, 3rd, 6th and 9th months were 16.52, 16.05, 16 and 16 mmHg respectively in POAG group. These levels were 23.34, 23.26, 22.66 and 22.89 mmHg in OHT group; 14.61, 14.7, 14.76 and 14.44 mmHg respectively in NTG group; 13.43, 13.21, 13.36 and 13.36 mmHg respectively in normal subjects. Mean RNFL measurements at baseline, 3rd, 6th and 9th months were 104.96, 105.01, 104.73 and 104.47 micron respectively in POAG group. These levels were 125.17, 124.77, 125.89 and 126.8 micron in OHT group; 99.47, 97.97, 95.36 and 95.44 micron in NTG group; 130.46, 132.75, 134.5 and 133.86 micron in normal subjects respectively. There were statistically significant differences between all groups for IOP and RNFL analysis (p<0.0001). POBF measurements at baseline, 3rd, 6th and 9th months were 15,74, 16.62, 16.07, 15.3 µl/sec respectively in POAG group. These levels were 17.52, 17.05, 17.76 and 18.06 µl/sec in OHT group; 17.2, 16.21, 15.58 and 15.09 µl/sec in NTG group; 19.99, 19.78, 20.36 and 20.56 µl/sec in normal subjects respectively. There was statistically significant difference of POBF measurements parameters between all groups (p<0.0001).Because none of the patients in POAG, NTG and OHT groups did not represent a significant progression in terms of perimetric and RNFL analysis during the study period, any relationship between POBF analysis and glaucoma progression could not be calculated. But POBF analysis was found as a significant factor to distinguish NTG patients from healthy subjects by means of logistic regression analysis.Conclusion: POBF can play a protecting role in progression of NTG. Although our results provide that POBF is a discriminative factor between NTG patients and healthy subjects, larger-scale prospective studies will be needed to assess the effect of POBF to glaucoma progression.